1988 lines
53 KiB
C
1988 lines
53 KiB
C
/*
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* zcache.c
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*
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* Copyright (c) 2010,2011, Dan Magenheimer, Oracle Corp.
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* Copyright (c) 2010,2011, Nitin Gupta
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*
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* Zcache provides an in-kernel "host implementation" for transcendent memory
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* and, thus indirectly, for cleancache and frontswap. Zcache includes two
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* page-accessible memory [1] interfaces, both utilizing lzo1x compression:
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* 1) "compression buddies" ("zbud") is used for ephemeral pages
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* 2) xvmalloc is used for persistent pages.
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* Xvmalloc (based on the TLSF allocator) has very low fragmentation
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* so maximizes space efficiency, while zbud allows pairs (and potentially,
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* in the future, more than a pair of) compressed pages to be closely linked
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* so that reclaiming can be done via the kernel's physical-page-oriented
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* "shrinker" interface.
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*
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* [1] For a definition of page-accessible memory (aka PAM), see:
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* http://marc.info/?l=linux-mm&m=127811271605009
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*/
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#include <linux/module.h>
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#include <linux/cpu.h>
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#include <linux/highmem.h>
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#include <linux/list.h>
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#include <linux/lzo.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/types.h>
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#include <linux/atomic.h>
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#include <linux/math64.h>
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#include "tmem.h"
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#include "../zram/xvmalloc.h" /* if built in drivers/staging */
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#if (!defined(CONFIG_CLEANCACHE) && !defined(CONFIG_FRONTSWAP))
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#error "zcache is useless without CONFIG_CLEANCACHE or CONFIG_FRONTSWAP"
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#endif
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#ifdef CONFIG_CLEANCACHE
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#include <linux/cleancache.h>
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#endif
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#ifdef CONFIG_FRONTSWAP
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#include <linux/frontswap.h>
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#endif
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#if 0
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/* this is more aggressive but may cause other problems? */
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#define ZCACHE_GFP_MASK (GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN)
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#else
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#define ZCACHE_GFP_MASK \
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(__GFP_FS | __GFP_NORETRY | __GFP_NOWARN | __GFP_NOMEMALLOC)
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#endif
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#define MAX_POOLS_PER_CLIENT 16
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#define MAX_CLIENTS 16
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#define LOCAL_CLIENT ((uint16_t)-1)
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MODULE_LICENSE("GPL");
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struct zcache_client {
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struct tmem_pool *tmem_pools[MAX_POOLS_PER_CLIENT];
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struct xv_pool *xvpool;
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bool allocated;
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atomic_t refcount;
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};
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static struct zcache_client zcache_host;
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static struct zcache_client zcache_clients[MAX_CLIENTS];
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static inline uint16_t get_client_id_from_client(struct zcache_client *cli)
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{
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BUG_ON(cli == NULL);
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if (cli == &zcache_host)
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return LOCAL_CLIENT;
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return cli - &zcache_clients[0];
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}
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static inline bool is_local_client(struct zcache_client *cli)
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{
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return cli == &zcache_host;
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}
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/**********
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* Compression buddies ("zbud") provides for packing two (or, possibly
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* in the future, more) compressed ephemeral pages into a single "raw"
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* (physical) page and tracking them with data structures so that
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* the raw pages can be easily reclaimed.
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*
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* A zbud page ("zbpg") is an aligned page containing a list_head,
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* a lock, and two "zbud headers". The remainder of the physical
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* page is divided up into aligned 64-byte "chunks" which contain
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* the compressed data for zero, one, or two zbuds. Each zbpg
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* resides on: (1) an "unused list" if it has no zbuds; (2) a
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* "buddied" list if it is fully populated with two zbuds; or
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* (3) one of PAGE_SIZE/64 "unbuddied" lists indexed by how many chunks
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* the one unbuddied zbud uses. The data inside a zbpg cannot be
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* read or written unless the zbpg's lock is held.
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*/
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#define ZBH_SENTINEL 0x43214321
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#define ZBPG_SENTINEL 0xdeadbeef
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#define ZBUD_MAX_BUDS 2
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struct zbud_hdr {
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uint16_t client_id;
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uint16_t pool_id;
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struct tmem_oid oid;
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uint32_t index;
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uint16_t size; /* compressed size in bytes, zero means unused */
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DECL_SENTINEL
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};
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struct zbud_page {
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struct list_head bud_list;
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spinlock_t lock;
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struct zbud_hdr buddy[ZBUD_MAX_BUDS];
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DECL_SENTINEL
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/* followed by NUM_CHUNK aligned CHUNK_SIZE-byte chunks */
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};
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#define CHUNK_SHIFT 6
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#define CHUNK_SIZE (1 << CHUNK_SHIFT)
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#define CHUNK_MASK (~(CHUNK_SIZE-1))
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#define NCHUNKS (((PAGE_SIZE - sizeof(struct zbud_page)) & \
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CHUNK_MASK) >> CHUNK_SHIFT)
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#define MAX_CHUNK (NCHUNKS-1)
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static struct {
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struct list_head list;
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unsigned count;
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} zbud_unbuddied[NCHUNKS];
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/* list N contains pages with N chunks USED and NCHUNKS-N unused */
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/* element 0 is never used but optimizing that isn't worth it */
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static unsigned long zbud_cumul_chunk_counts[NCHUNKS];
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struct list_head zbud_buddied_list;
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static unsigned long zcache_zbud_buddied_count;
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/* protects the buddied list and all unbuddied lists */
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static DEFINE_SPINLOCK(zbud_budlists_spinlock);
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static LIST_HEAD(zbpg_unused_list);
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static unsigned long zcache_zbpg_unused_list_count;
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/* protects the unused page list */
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static DEFINE_SPINLOCK(zbpg_unused_list_spinlock);
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static atomic_t zcache_zbud_curr_raw_pages;
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static atomic_t zcache_zbud_curr_zpages;
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static unsigned long zcache_zbud_curr_zbytes;
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static unsigned long zcache_zbud_cumul_zpages;
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static unsigned long zcache_zbud_cumul_zbytes;
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static unsigned long zcache_compress_poor;
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static unsigned long zcache_mean_compress_poor;
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/* forward references */
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static void *zcache_get_free_page(void);
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static void zcache_free_page(void *p);
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/*
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* zbud helper functions
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*/
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static inline unsigned zbud_max_buddy_size(void)
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{
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return MAX_CHUNK << CHUNK_SHIFT;
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}
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static inline unsigned zbud_size_to_chunks(unsigned size)
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{
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BUG_ON(size == 0 || size > zbud_max_buddy_size());
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return (size + CHUNK_SIZE - 1) >> CHUNK_SHIFT;
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}
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static inline int zbud_budnum(struct zbud_hdr *zh)
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{
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unsigned offset = (unsigned long)zh & (PAGE_SIZE - 1);
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struct zbud_page *zbpg = NULL;
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unsigned budnum = -1U;
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int i;
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for (i = 0; i < ZBUD_MAX_BUDS; i++)
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if (offset == offsetof(typeof(*zbpg), buddy[i])) {
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budnum = i;
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break;
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}
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BUG_ON(budnum == -1U);
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return budnum;
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}
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static char *zbud_data(struct zbud_hdr *zh, unsigned size)
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{
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struct zbud_page *zbpg;
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char *p;
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unsigned budnum;
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ASSERT_SENTINEL(zh, ZBH);
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budnum = zbud_budnum(zh);
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BUG_ON(size == 0 || size > zbud_max_buddy_size());
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zbpg = container_of(zh, struct zbud_page, buddy[budnum]);
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ASSERT_SPINLOCK(&zbpg->lock);
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p = (char *)zbpg;
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if (budnum == 0)
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p += ((sizeof(struct zbud_page) + CHUNK_SIZE - 1) &
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CHUNK_MASK);
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else if (budnum == 1)
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p += PAGE_SIZE - ((size + CHUNK_SIZE - 1) & CHUNK_MASK);
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return p;
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}
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/*
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* zbud raw page management
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*/
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static struct zbud_page *zbud_alloc_raw_page(void)
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{
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struct zbud_page *zbpg = NULL;
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struct zbud_hdr *zh0, *zh1;
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bool recycled = 0;
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/* if any pages on the zbpg list, use one */
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spin_lock(&zbpg_unused_list_spinlock);
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if (!list_empty(&zbpg_unused_list)) {
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zbpg = list_first_entry(&zbpg_unused_list,
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struct zbud_page, bud_list);
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list_del_init(&zbpg->bud_list);
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zcache_zbpg_unused_list_count--;
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recycled = 1;
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}
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spin_unlock(&zbpg_unused_list_spinlock);
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if (zbpg == NULL)
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/* none on zbpg list, try to get a kernel page */
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zbpg = zcache_get_free_page();
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if (likely(zbpg != NULL)) {
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INIT_LIST_HEAD(&zbpg->bud_list);
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zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1];
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spin_lock_init(&zbpg->lock);
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if (recycled) {
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ASSERT_INVERTED_SENTINEL(zbpg, ZBPG);
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SET_SENTINEL(zbpg, ZBPG);
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BUG_ON(zh0->size != 0 || tmem_oid_valid(&zh0->oid));
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BUG_ON(zh1->size != 0 || tmem_oid_valid(&zh1->oid));
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} else {
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atomic_inc(&zcache_zbud_curr_raw_pages);
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INIT_LIST_HEAD(&zbpg->bud_list);
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SET_SENTINEL(zbpg, ZBPG);
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zh0->size = 0; zh1->size = 0;
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tmem_oid_set_invalid(&zh0->oid);
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tmem_oid_set_invalid(&zh1->oid);
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}
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}
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return zbpg;
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}
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static void zbud_free_raw_page(struct zbud_page *zbpg)
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{
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struct zbud_hdr *zh0 = &zbpg->buddy[0], *zh1 = &zbpg->buddy[1];
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ASSERT_SENTINEL(zbpg, ZBPG);
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BUG_ON(!list_empty(&zbpg->bud_list));
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ASSERT_SPINLOCK(&zbpg->lock);
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BUG_ON(zh0->size != 0 || tmem_oid_valid(&zh0->oid));
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BUG_ON(zh1->size != 0 || tmem_oid_valid(&zh1->oid));
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INVERT_SENTINEL(zbpg, ZBPG);
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spin_unlock(&zbpg->lock);
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spin_lock(&zbpg_unused_list_spinlock);
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list_add(&zbpg->bud_list, &zbpg_unused_list);
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zcache_zbpg_unused_list_count++;
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spin_unlock(&zbpg_unused_list_spinlock);
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}
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/*
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* core zbud handling routines
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*/
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static unsigned zbud_free(struct zbud_hdr *zh)
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{
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unsigned size;
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ASSERT_SENTINEL(zh, ZBH);
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BUG_ON(!tmem_oid_valid(&zh->oid));
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size = zh->size;
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BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size());
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zh->size = 0;
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tmem_oid_set_invalid(&zh->oid);
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INVERT_SENTINEL(zh, ZBH);
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zcache_zbud_curr_zbytes -= size;
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atomic_dec(&zcache_zbud_curr_zpages);
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return size;
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}
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static void zbud_free_and_delist(struct zbud_hdr *zh)
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{
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unsigned chunks;
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struct zbud_hdr *zh_other;
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unsigned budnum = zbud_budnum(zh), size;
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struct zbud_page *zbpg =
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container_of(zh, struct zbud_page, buddy[budnum]);
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spin_lock(&zbpg->lock);
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if (list_empty(&zbpg->bud_list)) {
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/* ignore zombie page... see zbud_evict_pages() */
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spin_unlock(&zbpg->lock);
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return;
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}
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size = zbud_free(zh);
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ASSERT_SPINLOCK(&zbpg->lock);
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zh_other = &zbpg->buddy[(budnum == 0) ? 1 : 0];
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if (zh_other->size == 0) { /* was unbuddied: unlist and free */
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chunks = zbud_size_to_chunks(size) ;
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spin_lock(&zbud_budlists_spinlock);
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BUG_ON(list_empty(&zbud_unbuddied[chunks].list));
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list_del_init(&zbpg->bud_list);
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zbud_unbuddied[chunks].count--;
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spin_unlock(&zbud_budlists_spinlock);
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zbud_free_raw_page(zbpg);
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} else { /* was buddied: move remaining buddy to unbuddied list */
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chunks = zbud_size_to_chunks(zh_other->size) ;
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spin_lock(&zbud_budlists_spinlock);
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list_del_init(&zbpg->bud_list);
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zcache_zbud_buddied_count--;
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list_add_tail(&zbpg->bud_list, &zbud_unbuddied[chunks].list);
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zbud_unbuddied[chunks].count++;
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spin_unlock(&zbud_budlists_spinlock);
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spin_unlock(&zbpg->lock);
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}
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}
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static struct zbud_hdr *zbud_create(uint16_t client_id, uint16_t pool_id,
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struct tmem_oid *oid,
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uint32_t index, struct page *page,
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void *cdata, unsigned size)
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{
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struct zbud_hdr *zh0, *zh1, *zh = NULL;
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struct zbud_page *zbpg = NULL, *ztmp;
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unsigned nchunks;
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char *to;
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int i, found_good_buddy = 0;
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nchunks = zbud_size_to_chunks(size) ;
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for (i = MAX_CHUNK - nchunks + 1; i > 0; i--) {
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spin_lock(&zbud_budlists_spinlock);
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if (!list_empty(&zbud_unbuddied[i].list)) {
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list_for_each_entry_safe(zbpg, ztmp,
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&zbud_unbuddied[i].list, bud_list) {
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if (spin_trylock(&zbpg->lock)) {
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found_good_buddy = i;
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goto found_unbuddied;
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}
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}
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}
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spin_unlock(&zbud_budlists_spinlock);
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}
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/* didn't find a good buddy, try allocating a new page */
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zbpg = zbud_alloc_raw_page();
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if (unlikely(zbpg == NULL))
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goto out;
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/* ok, have a page, now compress the data before taking locks */
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spin_lock(&zbud_budlists_spinlock);
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spin_lock(&zbpg->lock);
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list_add_tail(&zbpg->bud_list, &zbud_unbuddied[nchunks].list);
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zbud_unbuddied[nchunks].count++;
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zh = &zbpg->buddy[0];
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goto init_zh;
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found_unbuddied:
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ASSERT_SPINLOCK(&zbpg->lock);
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zh0 = &zbpg->buddy[0]; zh1 = &zbpg->buddy[1];
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BUG_ON(!((zh0->size == 0) ^ (zh1->size == 0)));
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if (zh0->size != 0) { /* buddy0 in use, buddy1 is vacant */
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ASSERT_SENTINEL(zh0, ZBH);
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zh = zh1;
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} else if (zh1->size != 0) { /* buddy1 in use, buddy0 is vacant */
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ASSERT_SENTINEL(zh1, ZBH);
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zh = zh0;
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} else
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BUG();
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list_del_init(&zbpg->bud_list);
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zbud_unbuddied[found_good_buddy].count--;
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list_add_tail(&zbpg->bud_list, &zbud_buddied_list);
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zcache_zbud_buddied_count++;
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init_zh:
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SET_SENTINEL(zh, ZBH);
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zh->size = size;
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zh->index = index;
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zh->oid = *oid;
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zh->pool_id = pool_id;
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zh->client_id = client_id;
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to = zbud_data(zh, size);
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memcpy(to, cdata, size);
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spin_unlock(&zbpg->lock);
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spin_unlock(&zbud_budlists_spinlock);
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zbud_cumul_chunk_counts[nchunks]++;
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atomic_inc(&zcache_zbud_curr_zpages);
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zcache_zbud_cumul_zpages++;
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zcache_zbud_curr_zbytes += size;
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zcache_zbud_cumul_zbytes += size;
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out:
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return zh;
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}
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static int zbud_decompress(struct page *page, struct zbud_hdr *zh)
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{
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struct zbud_page *zbpg;
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unsigned budnum = zbud_budnum(zh);
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size_t out_len = PAGE_SIZE;
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char *to_va, *from_va;
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unsigned size;
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int ret = 0;
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zbpg = container_of(zh, struct zbud_page, buddy[budnum]);
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spin_lock(&zbpg->lock);
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if (list_empty(&zbpg->bud_list)) {
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/* ignore zombie page... see zbud_evict_pages() */
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ret = -EINVAL;
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goto out;
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}
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ASSERT_SENTINEL(zh, ZBH);
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BUG_ON(zh->size == 0 || zh->size > zbud_max_buddy_size());
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to_va = kmap_atomic(page, KM_USER0);
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size = zh->size;
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from_va = zbud_data(zh, size);
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ret = lzo1x_decompress_safe(from_va, size, to_va, &out_len);
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BUG_ON(ret != LZO_E_OK);
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BUG_ON(out_len != PAGE_SIZE);
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kunmap_atomic(to_va, KM_USER0);
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out:
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spin_unlock(&zbpg->lock);
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return ret;
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}
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/*
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* The following routines handle shrinking of ephemeral pages by evicting
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* pages "least valuable" first.
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*/
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static unsigned long zcache_evicted_raw_pages;
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static unsigned long zcache_evicted_buddied_pages;
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static unsigned long zcache_evicted_unbuddied_pages;
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static struct tmem_pool *zcache_get_pool_by_id(uint16_t cli_id,
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uint16_t poolid);
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static void zcache_put_pool(struct tmem_pool *pool);
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/*
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* Flush and free all zbuds in a zbpg, then free the pageframe
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*/
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static void zbud_evict_zbpg(struct zbud_page *zbpg)
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{
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struct zbud_hdr *zh;
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int i, j;
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uint32_t pool_id[ZBUD_MAX_BUDS], client_id[ZBUD_MAX_BUDS];
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uint32_t index[ZBUD_MAX_BUDS];
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struct tmem_oid oid[ZBUD_MAX_BUDS];
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struct tmem_pool *pool;
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ASSERT_SPINLOCK(&zbpg->lock);
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BUG_ON(!list_empty(&zbpg->bud_list));
|
|
for (i = 0, j = 0; i < ZBUD_MAX_BUDS; i++) {
|
|
zh = &zbpg->buddy[i];
|
|
if (zh->size) {
|
|
client_id[j] = zh->client_id;
|
|
pool_id[j] = zh->pool_id;
|
|
oid[j] = zh->oid;
|
|
index[j] = zh->index;
|
|
j++;
|
|
zbud_free(zh);
|
|
}
|
|
}
|
|
spin_unlock(&zbpg->lock);
|
|
for (i = 0; i < j; i++) {
|
|
pool = zcache_get_pool_by_id(client_id[i], pool_id[i]);
|
|
if (pool != NULL) {
|
|
tmem_flush_page(pool, &oid[i], index[i]);
|
|
zcache_put_pool(pool);
|
|
}
|
|
}
|
|
ASSERT_SENTINEL(zbpg, ZBPG);
|
|
spin_lock(&zbpg->lock);
|
|
zbud_free_raw_page(zbpg);
|
|
}
|
|
|
|
/*
|
|
* Free nr pages. This code is funky because we want to hold the locks
|
|
* protecting various lists for as short a time as possible, and in some
|
|
* circumstances the list may change asynchronously when the list lock is
|
|
* not held. In some cases we also trylock not only to avoid waiting on a
|
|
* page in use by another cpu, but also to avoid potential deadlock due to
|
|
* lock inversion.
|
|
*/
|
|
static void zbud_evict_pages(int nr)
|
|
{
|
|
struct zbud_page *zbpg;
|
|
int i;
|
|
|
|
/* first try freeing any pages on unused list */
|
|
retry_unused_list:
|
|
spin_lock_bh(&zbpg_unused_list_spinlock);
|
|
if (!list_empty(&zbpg_unused_list)) {
|
|
/* can't walk list here, since it may change when unlocked */
|
|
zbpg = list_first_entry(&zbpg_unused_list,
|
|
struct zbud_page, bud_list);
|
|
list_del_init(&zbpg->bud_list);
|
|
zcache_zbpg_unused_list_count--;
|
|
atomic_dec(&zcache_zbud_curr_raw_pages);
|
|
spin_unlock_bh(&zbpg_unused_list_spinlock);
|
|
zcache_free_page(zbpg);
|
|
zcache_evicted_raw_pages++;
|
|
if (--nr <= 0)
|
|
goto out;
|
|
goto retry_unused_list;
|
|
}
|
|
spin_unlock_bh(&zbpg_unused_list_spinlock);
|
|
|
|
/* now try freeing unbuddied pages, starting with least space avail */
|
|
for (i = 0; i < MAX_CHUNK; i++) {
|
|
retry_unbud_list_i:
|
|
spin_lock_bh(&zbud_budlists_spinlock);
|
|
if (list_empty(&zbud_unbuddied[i].list)) {
|
|
spin_unlock_bh(&zbud_budlists_spinlock);
|
|
continue;
|
|
}
|
|
list_for_each_entry(zbpg, &zbud_unbuddied[i].list, bud_list) {
|
|
if (unlikely(!spin_trylock(&zbpg->lock)))
|
|
continue;
|
|
list_del_init(&zbpg->bud_list);
|
|
zbud_unbuddied[i].count--;
|
|
spin_unlock(&zbud_budlists_spinlock);
|
|
zcache_evicted_unbuddied_pages++;
|
|
/* want budlists unlocked when doing zbpg eviction */
|
|
zbud_evict_zbpg(zbpg);
|
|
local_bh_enable();
|
|
if (--nr <= 0)
|
|
goto out;
|
|
goto retry_unbud_list_i;
|
|
}
|
|
spin_unlock_bh(&zbud_budlists_spinlock);
|
|
}
|
|
|
|
/* as a last resort, free buddied pages */
|
|
retry_bud_list:
|
|
spin_lock_bh(&zbud_budlists_spinlock);
|
|
if (list_empty(&zbud_buddied_list)) {
|
|
spin_unlock_bh(&zbud_budlists_spinlock);
|
|
goto out;
|
|
}
|
|
list_for_each_entry(zbpg, &zbud_buddied_list, bud_list) {
|
|
if (unlikely(!spin_trylock(&zbpg->lock)))
|
|
continue;
|
|
list_del_init(&zbpg->bud_list);
|
|
zcache_zbud_buddied_count--;
|
|
spin_unlock(&zbud_budlists_spinlock);
|
|
zcache_evicted_buddied_pages++;
|
|
/* want budlists unlocked when doing zbpg eviction */
|
|
zbud_evict_zbpg(zbpg);
|
|
local_bh_enable();
|
|
if (--nr <= 0)
|
|
goto out;
|
|
goto retry_bud_list;
|
|
}
|
|
spin_unlock_bh(&zbud_budlists_spinlock);
|
|
out:
|
|
return;
|
|
}
|
|
|
|
static void zbud_init(void)
|
|
{
|
|
int i;
|
|
|
|
INIT_LIST_HEAD(&zbud_buddied_list);
|
|
zcache_zbud_buddied_count = 0;
|
|
for (i = 0; i < NCHUNKS; i++) {
|
|
INIT_LIST_HEAD(&zbud_unbuddied[i].list);
|
|
zbud_unbuddied[i].count = 0;
|
|
}
|
|
}
|
|
|
|
#ifdef CONFIG_SYSFS
|
|
/*
|
|
* These sysfs routines show a nice distribution of how many zbpg's are
|
|
* currently (and have ever been placed) in each unbuddied list. It's fun
|
|
* to watch but can probably go away before final merge.
|
|
*/
|
|
static int zbud_show_unbuddied_list_counts(char *buf)
|
|
{
|
|
int i;
|
|
char *p = buf;
|
|
|
|
for (i = 0; i < NCHUNKS; i++)
|
|
p += sprintf(p, "%u ", zbud_unbuddied[i].count);
|
|
return p - buf;
|
|
}
|
|
|
|
static int zbud_show_cumul_chunk_counts(char *buf)
|
|
{
|
|
unsigned long i, chunks = 0, total_chunks = 0, sum_total_chunks = 0;
|
|
unsigned long total_chunks_lte_21 = 0, total_chunks_lte_32 = 0;
|
|
unsigned long total_chunks_lte_42 = 0;
|
|
char *p = buf;
|
|
|
|
for (i = 0; i < NCHUNKS; i++) {
|
|
p += sprintf(p, "%lu ", zbud_cumul_chunk_counts[i]);
|
|
chunks += zbud_cumul_chunk_counts[i];
|
|
total_chunks += zbud_cumul_chunk_counts[i];
|
|
sum_total_chunks += i * zbud_cumul_chunk_counts[i];
|
|
if (i == 21)
|
|
total_chunks_lte_21 = total_chunks;
|
|
if (i == 32)
|
|
total_chunks_lte_32 = total_chunks;
|
|
if (i == 42)
|
|
total_chunks_lte_42 = total_chunks;
|
|
}
|
|
p += sprintf(p, "<=21:%lu <=32:%lu <=42:%lu, mean:%lu\n",
|
|
total_chunks_lte_21, total_chunks_lte_32, total_chunks_lte_42,
|
|
chunks == 0 ? 0 : sum_total_chunks / chunks);
|
|
return p - buf;
|
|
}
|
|
#endif
|
|
|
|
/**********
|
|
* This "zv" PAM implementation combines the TLSF-based xvMalloc
|
|
* with lzo1x compression to maximize the amount of data that can
|
|
* be packed into a physical page.
|
|
*
|
|
* Zv represents a PAM page with the index and object (plus a "size" value
|
|
* necessary for decompression) immediately preceding the compressed data.
|
|
*/
|
|
|
|
#define ZVH_SENTINEL 0x43214321
|
|
|
|
struct zv_hdr {
|
|
uint32_t pool_id;
|
|
struct tmem_oid oid;
|
|
uint32_t index;
|
|
DECL_SENTINEL
|
|
};
|
|
|
|
/* rudimentary policy limits */
|
|
/* total number of persistent pages may not exceed this percentage */
|
|
static unsigned int zv_page_count_policy_percent = 75;
|
|
/*
|
|
* byte count defining poor compression; pages with greater zsize will be
|
|
* rejected
|
|
*/
|
|
static unsigned int zv_max_zsize = (PAGE_SIZE / 8) * 7;
|
|
/*
|
|
* byte count defining poor *mean* compression; pages with greater zsize
|
|
* will be rejected until sufficient better-compressed pages are accepted
|
|
* driving the mean below this threshold
|
|
*/
|
|
static unsigned int zv_max_mean_zsize = (PAGE_SIZE / 8) * 5;
|
|
|
|
static atomic_t zv_curr_dist_counts[NCHUNKS];
|
|
static atomic_t zv_cumul_dist_counts[NCHUNKS];
|
|
|
|
static struct zv_hdr *zv_create(struct xv_pool *xvpool, uint32_t pool_id,
|
|
struct tmem_oid *oid, uint32_t index,
|
|
void *cdata, unsigned clen)
|
|
{
|
|
struct page *page;
|
|
struct zv_hdr *zv = NULL;
|
|
uint32_t offset;
|
|
int alloc_size = clen + sizeof(struct zv_hdr);
|
|
int chunks = (alloc_size + (CHUNK_SIZE - 1)) >> CHUNK_SHIFT;
|
|
int ret;
|
|
|
|
BUG_ON(!irqs_disabled());
|
|
BUG_ON(chunks >= NCHUNKS);
|
|
ret = xv_malloc(xvpool, alloc_size,
|
|
&page, &offset, ZCACHE_GFP_MASK);
|
|
if (unlikely(ret))
|
|
goto out;
|
|
atomic_inc(&zv_curr_dist_counts[chunks]);
|
|
atomic_inc(&zv_cumul_dist_counts[chunks]);
|
|
zv = kmap_atomic(page, KM_USER0) + offset;
|
|
zv->index = index;
|
|
zv->oid = *oid;
|
|
zv->pool_id = pool_id;
|
|
SET_SENTINEL(zv, ZVH);
|
|
memcpy((char *)zv + sizeof(struct zv_hdr), cdata, clen);
|
|
kunmap_atomic(zv, KM_USER0);
|
|
out:
|
|
return zv;
|
|
}
|
|
|
|
static void zv_free(struct xv_pool *xvpool, struct zv_hdr *zv)
|
|
{
|
|
unsigned long flags;
|
|
struct page *page;
|
|
uint32_t offset;
|
|
uint16_t size = xv_get_object_size(zv);
|
|
int chunks = (size + (CHUNK_SIZE - 1)) >> CHUNK_SHIFT;
|
|
|
|
ASSERT_SENTINEL(zv, ZVH);
|
|
BUG_ON(chunks >= NCHUNKS);
|
|
atomic_dec(&zv_curr_dist_counts[chunks]);
|
|
size -= sizeof(*zv);
|
|
BUG_ON(size == 0);
|
|
INVERT_SENTINEL(zv, ZVH);
|
|
page = virt_to_page(zv);
|
|
offset = (unsigned long)zv & ~PAGE_MASK;
|
|
local_irq_save(flags);
|
|
xv_free(xvpool, page, offset);
|
|
local_irq_restore(flags);
|
|
}
|
|
|
|
static void zv_decompress(struct page *page, struct zv_hdr *zv)
|
|
{
|
|
size_t clen = PAGE_SIZE;
|
|
char *to_va;
|
|
unsigned size;
|
|
int ret;
|
|
|
|
ASSERT_SENTINEL(zv, ZVH);
|
|
size = xv_get_object_size(zv) - sizeof(*zv);
|
|
BUG_ON(size == 0);
|
|
to_va = kmap_atomic(page, KM_USER0);
|
|
ret = lzo1x_decompress_safe((char *)zv + sizeof(*zv),
|
|
size, to_va, &clen);
|
|
kunmap_atomic(to_va, KM_USER0);
|
|
BUG_ON(ret != LZO_E_OK);
|
|
BUG_ON(clen != PAGE_SIZE);
|
|
}
|
|
|
|
#ifdef CONFIG_SYSFS
|
|
/*
|
|
* show a distribution of compression stats for zv pages.
|
|
*/
|
|
|
|
static int zv_curr_dist_counts_show(char *buf)
|
|
{
|
|
unsigned long i, n, chunks = 0, sum_total_chunks = 0;
|
|
char *p = buf;
|
|
|
|
for (i = 0; i < NCHUNKS; i++) {
|
|
n = atomic_read(&zv_curr_dist_counts[i]);
|
|
p += sprintf(p, "%lu ", n);
|
|
chunks += n;
|
|
sum_total_chunks += i * n;
|
|
}
|
|
p += sprintf(p, "mean:%lu\n",
|
|
chunks == 0 ? 0 : sum_total_chunks / chunks);
|
|
return p - buf;
|
|
}
|
|
|
|
static int zv_cumul_dist_counts_show(char *buf)
|
|
{
|
|
unsigned long i, n, chunks = 0, sum_total_chunks = 0;
|
|
char *p = buf;
|
|
|
|
for (i = 0; i < NCHUNKS; i++) {
|
|
n = atomic_read(&zv_cumul_dist_counts[i]);
|
|
p += sprintf(p, "%lu ", n);
|
|
chunks += n;
|
|
sum_total_chunks += i * n;
|
|
}
|
|
p += sprintf(p, "mean:%lu\n",
|
|
chunks == 0 ? 0 : sum_total_chunks / chunks);
|
|
return p - buf;
|
|
}
|
|
|
|
/*
|
|
* setting zv_max_zsize via sysfs causes all persistent (e.g. swap)
|
|
* pages that don't compress to less than this value (including metadata
|
|
* overhead) to be rejected. We don't allow the value to get too close
|
|
* to PAGE_SIZE.
|
|
*/
|
|
static ssize_t zv_max_zsize_show(struct kobject *kobj,
|
|
struct kobj_attribute *attr,
|
|
char *buf)
|
|
{
|
|
return sprintf(buf, "%u\n", zv_max_zsize);
|
|
}
|
|
|
|
static ssize_t zv_max_zsize_store(struct kobject *kobj,
|
|
struct kobj_attribute *attr,
|
|
const char *buf, size_t count)
|
|
{
|
|
unsigned long val;
|
|
int err;
|
|
|
|
if (!capable(CAP_SYS_ADMIN))
|
|
return -EPERM;
|
|
|
|
err = kstrtoul(buf, 10, &val);
|
|
if (err || (val == 0) || (val > (PAGE_SIZE / 8) * 7))
|
|
return -EINVAL;
|
|
zv_max_zsize = val;
|
|
return count;
|
|
}
|
|
|
|
/*
|
|
* setting zv_max_mean_zsize via sysfs causes all persistent (e.g. swap)
|
|
* pages that don't compress to less than this value (including metadata
|
|
* overhead) to be rejected UNLESS the mean compression is also smaller
|
|
* than this value. In other words, we are load-balancing-by-zsize the
|
|
* accepted pages. Again, we don't allow the value to get too close
|
|
* to PAGE_SIZE.
|
|
*/
|
|
static ssize_t zv_max_mean_zsize_show(struct kobject *kobj,
|
|
struct kobj_attribute *attr,
|
|
char *buf)
|
|
{
|
|
return sprintf(buf, "%u\n", zv_max_mean_zsize);
|
|
}
|
|
|
|
static ssize_t zv_max_mean_zsize_store(struct kobject *kobj,
|
|
struct kobj_attribute *attr,
|
|
const char *buf, size_t count)
|
|
{
|
|
unsigned long val;
|
|
int err;
|
|
|
|
if (!capable(CAP_SYS_ADMIN))
|
|
return -EPERM;
|
|
|
|
err = kstrtoul(buf, 10, &val);
|
|
if (err || (val == 0) || (val > (PAGE_SIZE / 8) * 7))
|
|
return -EINVAL;
|
|
zv_max_mean_zsize = val;
|
|
return count;
|
|
}
|
|
|
|
/*
|
|
* setting zv_page_count_policy_percent via sysfs sets an upper bound of
|
|
* persistent (e.g. swap) pages that will be retained according to:
|
|
* (zv_page_count_policy_percent * totalram_pages) / 100)
|
|
* when that limit is reached, further puts will be rejected (until
|
|
* some pages have been flushed). Note that, due to compression,
|
|
* this number may exceed 100; it defaults to 75 and we set an
|
|
* arbitary limit of 150. A poor choice will almost certainly result
|
|
* in OOM's, so this value should only be changed prudently.
|
|
*/
|
|
static ssize_t zv_page_count_policy_percent_show(struct kobject *kobj,
|
|
struct kobj_attribute *attr,
|
|
char *buf)
|
|
{
|
|
return sprintf(buf, "%u\n", zv_page_count_policy_percent);
|
|
}
|
|
|
|
static ssize_t zv_page_count_policy_percent_store(struct kobject *kobj,
|
|
struct kobj_attribute *attr,
|
|
const char *buf, size_t count)
|
|
{
|
|
unsigned long val;
|
|
int err;
|
|
|
|
if (!capable(CAP_SYS_ADMIN))
|
|
return -EPERM;
|
|
|
|
err = kstrtoul(buf, 10, &val);
|
|
if (err || (val == 0) || (val > 150))
|
|
return -EINVAL;
|
|
zv_page_count_policy_percent = val;
|
|
return count;
|
|
}
|
|
|
|
static struct kobj_attribute zcache_zv_max_zsize_attr = {
|
|
.attr = { .name = "zv_max_zsize", .mode = 0644 },
|
|
.show = zv_max_zsize_show,
|
|
.store = zv_max_zsize_store,
|
|
};
|
|
|
|
static struct kobj_attribute zcache_zv_max_mean_zsize_attr = {
|
|
.attr = { .name = "zv_max_mean_zsize", .mode = 0644 },
|
|
.show = zv_max_mean_zsize_show,
|
|
.store = zv_max_mean_zsize_store,
|
|
};
|
|
|
|
static struct kobj_attribute zcache_zv_page_count_policy_percent_attr = {
|
|
.attr = { .name = "zv_page_count_policy_percent",
|
|
.mode = 0644 },
|
|
.show = zv_page_count_policy_percent_show,
|
|
.store = zv_page_count_policy_percent_store,
|
|
};
|
|
#endif
|
|
|
|
/*
|
|
* zcache core code starts here
|
|
*/
|
|
|
|
/* useful stats not collected by cleancache or frontswap */
|
|
static unsigned long zcache_flush_total;
|
|
static unsigned long zcache_flush_found;
|
|
static unsigned long zcache_flobj_total;
|
|
static unsigned long zcache_flobj_found;
|
|
static unsigned long zcache_failed_eph_puts;
|
|
static unsigned long zcache_failed_pers_puts;
|
|
|
|
/*
|
|
* Tmem operations assume the poolid implies the invoking client.
|
|
* Zcache only has one client (the kernel itself): LOCAL_CLIENT.
|
|
* RAMster has each client numbered by cluster node, and a KVM version
|
|
* of zcache would have one client per guest and each client might
|
|
* have a poolid==N.
|
|
*/
|
|
static struct tmem_pool *zcache_get_pool_by_id(uint16_t cli_id, uint16_t poolid)
|
|
{
|
|
struct tmem_pool *pool = NULL;
|
|
struct zcache_client *cli = NULL;
|
|
|
|
if (cli_id == LOCAL_CLIENT)
|
|
cli = &zcache_host;
|
|
else {
|
|
if (cli_id >= MAX_CLIENTS)
|
|
goto out;
|
|
cli = &zcache_clients[cli_id];
|
|
if (cli == NULL)
|
|
goto out;
|
|
atomic_inc(&cli->refcount);
|
|
}
|
|
if (poolid < MAX_POOLS_PER_CLIENT) {
|
|
pool = cli->tmem_pools[poolid];
|
|
if (pool != NULL)
|
|
atomic_inc(&pool->refcount);
|
|
}
|
|
out:
|
|
return pool;
|
|
}
|
|
|
|
static void zcache_put_pool(struct tmem_pool *pool)
|
|
{
|
|
struct zcache_client *cli = NULL;
|
|
|
|
if (pool == NULL)
|
|
BUG();
|
|
cli = pool->client;
|
|
atomic_dec(&pool->refcount);
|
|
atomic_dec(&cli->refcount);
|
|
}
|
|
|
|
int zcache_new_client(uint16_t cli_id)
|
|
{
|
|
struct zcache_client *cli = NULL;
|
|
int ret = -1;
|
|
|
|
if (cli_id == LOCAL_CLIENT)
|
|
cli = &zcache_host;
|
|
else if ((unsigned int)cli_id < MAX_CLIENTS)
|
|
cli = &zcache_clients[cli_id];
|
|
if (cli == NULL)
|
|
goto out;
|
|
if (cli->allocated)
|
|
goto out;
|
|
cli->allocated = 1;
|
|
#ifdef CONFIG_FRONTSWAP
|
|
cli->xvpool = xv_create_pool();
|
|
if (cli->xvpool == NULL)
|
|
goto out;
|
|
#endif
|
|
ret = 0;
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
/* counters for debugging */
|
|
static unsigned long zcache_failed_get_free_pages;
|
|
static unsigned long zcache_failed_alloc;
|
|
static unsigned long zcache_put_to_flush;
|
|
|
|
/*
|
|
* for now, used named slabs so can easily track usage; later can
|
|
* either just use kmalloc, or perhaps add a slab-like allocator
|
|
* to more carefully manage total memory utilization
|
|
*/
|
|
static struct kmem_cache *zcache_objnode_cache;
|
|
static struct kmem_cache *zcache_obj_cache;
|
|
static atomic_t zcache_curr_obj_count = ATOMIC_INIT(0);
|
|
static unsigned long zcache_curr_obj_count_max;
|
|
static atomic_t zcache_curr_objnode_count = ATOMIC_INIT(0);
|
|
static unsigned long zcache_curr_objnode_count_max;
|
|
|
|
/*
|
|
* to avoid memory allocation recursion (e.g. due to direct reclaim), we
|
|
* preload all necessary data structures so the hostops callbacks never
|
|
* actually do a malloc
|
|
*/
|
|
struct zcache_preload {
|
|
void *page;
|
|
struct tmem_obj *obj;
|
|
int nr;
|
|
struct tmem_objnode *objnodes[OBJNODE_TREE_MAX_PATH];
|
|
};
|
|
static DEFINE_PER_CPU(struct zcache_preload, zcache_preloads) = { 0, };
|
|
|
|
static int zcache_do_preload(struct tmem_pool *pool)
|
|
{
|
|
struct zcache_preload *kp;
|
|
struct tmem_objnode *objnode;
|
|
struct tmem_obj *obj;
|
|
void *page;
|
|
int ret = -ENOMEM;
|
|
|
|
if (unlikely(zcache_objnode_cache == NULL))
|
|
goto out;
|
|
if (unlikely(zcache_obj_cache == NULL))
|
|
goto out;
|
|
preempt_disable();
|
|
kp = &__get_cpu_var(zcache_preloads);
|
|
while (kp->nr < ARRAY_SIZE(kp->objnodes)) {
|
|
preempt_enable_no_resched();
|
|
objnode = kmem_cache_alloc(zcache_objnode_cache,
|
|
ZCACHE_GFP_MASK);
|
|
if (unlikely(objnode == NULL)) {
|
|
zcache_failed_alloc++;
|
|
goto out;
|
|
}
|
|
preempt_disable();
|
|
kp = &__get_cpu_var(zcache_preloads);
|
|
if (kp->nr < ARRAY_SIZE(kp->objnodes))
|
|
kp->objnodes[kp->nr++] = objnode;
|
|
else
|
|
kmem_cache_free(zcache_objnode_cache, objnode);
|
|
}
|
|
preempt_enable_no_resched();
|
|
obj = kmem_cache_alloc(zcache_obj_cache, ZCACHE_GFP_MASK);
|
|
if (unlikely(obj == NULL)) {
|
|
zcache_failed_alloc++;
|
|
goto out;
|
|
}
|
|
page = (void *)__get_free_page(ZCACHE_GFP_MASK);
|
|
if (unlikely(page == NULL)) {
|
|
zcache_failed_get_free_pages++;
|
|
kmem_cache_free(zcache_obj_cache, obj);
|
|
goto out;
|
|
}
|
|
preempt_disable();
|
|
kp = &__get_cpu_var(zcache_preloads);
|
|
if (kp->obj == NULL)
|
|
kp->obj = obj;
|
|
else
|
|
kmem_cache_free(zcache_obj_cache, obj);
|
|
if (kp->page == NULL)
|
|
kp->page = page;
|
|
else
|
|
free_page((unsigned long)page);
|
|
ret = 0;
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
static void *zcache_get_free_page(void)
|
|
{
|
|
struct zcache_preload *kp;
|
|
void *page;
|
|
|
|
kp = &__get_cpu_var(zcache_preloads);
|
|
page = kp->page;
|
|
BUG_ON(page == NULL);
|
|
kp->page = NULL;
|
|
return page;
|
|
}
|
|
|
|
static void zcache_free_page(void *p)
|
|
{
|
|
free_page((unsigned long)p);
|
|
}
|
|
|
|
/*
|
|
* zcache implementation for tmem host ops
|
|
*/
|
|
|
|
static struct tmem_objnode *zcache_objnode_alloc(struct tmem_pool *pool)
|
|
{
|
|
struct tmem_objnode *objnode = NULL;
|
|
unsigned long count;
|
|
struct zcache_preload *kp;
|
|
|
|
kp = &__get_cpu_var(zcache_preloads);
|
|
if (kp->nr <= 0)
|
|
goto out;
|
|
objnode = kp->objnodes[kp->nr - 1];
|
|
BUG_ON(objnode == NULL);
|
|
kp->objnodes[kp->nr - 1] = NULL;
|
|
kp->nr--;
|
|
count = atomic_inc_return(&zcache_curr_objnode_count);
|
|
if (count > zcache_curr_objnode_count_max)
|
|
zcache_curr_objnode_count_max = count;
|
|
out:
|
|
return objnode;
|
|
}
|
|
|
|
static void zcache_objnode_free(struct tmem_objnode *objnode,
|
|
struct tmem_pool *pool)
|
|
{
|
|
atomic_dec(&zcache_curr_objnode_count);
|
|
BUG_ON(atomic_read(&zcache_curr_objnode_count) < 0);
|
|
kmem_cache_free(zcache_objnode_cache, objnode);
|
|
}
|
|
|
|
static struct tmem_obj *zcache_obj_alloc(struct tmem_pool *pool)
|
|
{
|
|
struct tmem_obj *obj = NULL;
|
|
unsigned long count;
|
|
struct zcache_preload *kp;
|
|
|
|
kp = &__get_cpu_var(zcache_preloads);
|
|
obj = kp->obj;
|
|
BUG_ON(obj == NULL);
|
|
kp->obj = NULL;
|
|
count = atomic_inc_return(&zcache_curr_obj_count);
|
|
if (count > zcache_curr_obj_count_max)
|
|
zcache_curr_obj_count_max = count;
|
|
return obj;
|
|
}
|
|
|
|
static void zcache_obj_free(struct tmem_obj *obj, struct tmem_pool *pool)
|
|
{
|
|
atomic_dec(&zcache_curr_obj_count);
|
|
BUG_ON(atomic_read(&zcache_curr_obj_count) < 0);
|
|
kmem_cache_free(zcache_obj_cache, obj);
|
|
}
|
|
|
|
static struct tmem_hostops zcache_hostops = {
|
|
.obj_alloc = zcache_obj_alloc,
|
|
.obj_free = zcache_obj_free,
|
|
.objnode_alloc = zcache_objnode_alloc,
|
|
.objnode_free = zcache_objnode_free,
|
|
};
|
|
|
|
/*
|
|
* zcache implementations for PAM page descriptor ops
|
|
*/
|
|
|
|
static atomic_t zcache_curr_eph_pampd_count = ATOMIC_INIT(0);
|
|
static unsigned long zcache_curr_eph_pampd_count_max;
|
|
static atomic_t zcache_curr_pers_pampd_count = ATOMIC_INIT(0);
|
|
static unsigned long zcache_curr_pers_pampd_count_max;
|
|
|
|
/* forward reference */
|
|
static int zcache_compress(struct page *from, void **out_va, size_t *out_len);
|
|
|
|
static void *zcache_pampd_create(char *data, size_t size, bool raw, int eph,
|
|
struct tmem_pool *pool, struct tmem_oid *oid,
|
|
uint32_t index)
|
|
{
|
|
void *pampd = NULL, *cdata;
|
|
size_t clen;
|
|
int ret;
|
|
unsigned long count;
|
|
struct page *page = (struct page *)(data);
|
|
struct zcache_client *cli = pool->client;
|
|
uint16_t client_id = get_client_id_from_client(cli);
|
|
unsigned long zv_mean_zsize;
|
|
unsigned long curr_pers_pampd_count;
|
|
u64 total_zsize;
|
|
|
|
if (eph) {
|
|
ret = zcache_compress(page, &cdata, &clen);
|
|
if (ret == 0)
|
|
goto out;
|
|
if (clen == 0 || clen > zbud_max_buddy_size()) {
|
|
zcache_compress_poor++;
|
|
goto out;
|
|
}
|
|
pampd = (void *)zbud_create(client_id, pool->pool_id, oid,
|
|
index, page, cdata, clen);
|
|
if (pampd != NULL) {
|
|
count = atomic_inc_return(&zcache_curr_eph_pampd_count);
|
|
if (count > zcache_curr_eph_pampd_count_max)
|
|
zcache_curr_eph_pampd_count_max = count;
|
|
}
|
|
} else {
|
|
curr_pers_pampd_count =
|
|
atomic_read(&zcache_curr_pers_pampd_count);
|
|
if (curr_pers_pampd_count >
|
|
(zv_page_count_policy_percent * totalram_pages) / 100)
|
|
goto out;
|
|
ret = zcache_compress(page, &cdata, &clen);
|
|
if (ret == 0)
|
|
goto out;
|
|
/* reject if compression is too poor */
|
|
if (clen > zv_max_zsize) {
|
|
zcache_compress_poor++;
|
|
goto out;
|
|
}
|
|
/* reject if mean compression is too poor */
|
|
if ((clen > zv_max_mean_zsize) && (curr_pers_pampd_count > 0)) {
|
|
total_zsize = xv_get_total_size_bytes(cli->xvpool);
|
|
zv_mean_zsize = div_u64(total_zsize,
|
|
curr_pers_pampd_count);
|
|
if (zv_mean_zsize > zv_max_mean_zsize) {
|
|
zcache_mean_compress_poor++;
|
|
goto out;
|
|
}
|
|
}
|
|
pampd = (void *)zv_create(cli->xvpool, pool->pool_id,
|
|
oid, index, cdata, clen);
|
|
if (pampd == NULL)
|
|
goto out;
|
|
count = atomic_inc_return(&zcache_curr_pers_pampd_count);
|
|
if (count > zcache_curr_pers_pampd_count_max)
|
|
zcache_curr_pers_pampd_count_max = count;
|
|
}
|
|
out:
|
|
return pampd;
|
|
}
|
|
|
|
/*
|
|
* fill the pageframe corresponding to the struct page with the data
|
|
* from the passed pampd
|
|
*/
|
|
static int zcache_pampd_get_data(char *data, size_t *bufsize, bool raw,
|
|
void *pampd, struct tmem_pool *pool,
|
|
struct tmem_oid *oid, uint32_t index)
|
|
{
|
|
int ret = 0;
|
|
|
|
BUG_ON(is_ephemeral(pool));
|
|
zv_decompress((struct page *)(data), pampd);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* fill the pageframe corresponding to the struct page with the data
|
|
* from the passed pampd
|
|
*/
|
|
static int zcache_pampd_get_data_and_free(char *data, size_t *bufsize, bool raw,
|
|
void *pampd, struct tmem_pool *pool,
|
|
struct tmem_oid *oid, uint32_t index)
|
|
{
|
|
int ret = 0;
|
|
|
|
BUG_ON(!is_ephemeral(pool));
|
|
zbud_decompress((struct page *)(data), pampd);
|
|
zbud_free_and_delist((struct zbud_hdr *)pampd);
|
|
atomic_dec(&zcache_curr_eph_pampd_count);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* free the pampd and remove it from any zcache lists
|
|
* pampd must no longer be pointed to from any tmem data structures!
|
|
*/
|
|
static void zcache_pampd_free(void *pampd, struct tmem_pool *pool,
|
|
struct tmem_oid *oid, uint32_t index)
|
|
{
|
|
struct zcache_client *cli = pool->client;
|
|
|
|
if (is_ephemeral(pool)) {
|
|
zbud_free_and_delist((struct zbud_hdr *)pampd);
|
|
atomic_dec(&zcache_curr_eph_pampd_count);
|
|
BUG_ON(atomic_read(&zcache_curr_eph_pampd_count) < 0);
|
|
} else {
|
|
zv_free(cli->xvpool, (struct zv_hdr *)pampd);
|
|
atomic_dec(&zcache_curr_pers_pampd_count);
|
|
BUG_ON(atomic_read(&zcache_curr_pers_pampd_count) < 0);
|
|
}
|
|
}
|
|
|
|
static void zcache_pampd_free_obj(struct tmem_pool *pool, struct tmem_obj *obj)
|
|
{
|
|
}
|
|
|
|
static void zcache_pampd_new_obj(struct tmem_obj *obj)
|
|
{
|
|
}
|
|
|
|
static int zcache_pampd_replace_in_obj(void *pampd, struct tmem_obj *obj)
|
|
{
|
|
return -1;
|
|
}
|
|
|
|
static bool zcache_pampd_is_remote(void *pampd)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static struct tmem_pamops zcache_pamops = {
|
|
.create = zcache_pampd_create,
|
|
.get_data = zcache_pampd_get_data,
|
|
.get_data_and_free = zcache_pampd_get_data_and_free,
|
|
.free = zcache_pampd_free,
|
|
.free_obj = zcache_pampd_free_obj,
|
|
.new_obj = zcache_pampd_new_obj,
|
|
.replace_in_obj = zcache_pampd_replace_in_obj,
|
|
.is_remote = zcache_pampd_is_remote,
|
|
};
|
|
|
|
/*
|
|
* zcache compression/decompression and related per-cpu stuff
|
|
*/
|
|
|
|
#define LZO_WORKMEM_BYTES LZO1X_1_MEM_COMPRESS
|
|
#define LZO_DSTMEM_PAGE_ORDER 1
|
|
static DEFINE_PER_CPU(unsigned char *, zcache_workmem);
|
|
static DEFINE_PER_CPU(unsigned char *, zcache_dstmem);
|
|
|
|
static int zcache_compress(struct page *from, void **out_va, size_t *out_len)
|
|
{
|
|
int ret = 0;
|
|
unsigned char *dmem = __get_cpu_var(zcache_dstmem);
|
|
unsigned char *wmem = __get_cpu_var(zcache_workmem);
|
|
char *from_va;
|
|
|
|
BUG_ON(!irqs_disabled());
|
|
if (unlikely(dmem == NULL || wmem == NULL))
|
|
goto out; /* no buffer, so can't compress */
|
|
from_va = kmap_atomic(from, KM_USER0);
|
|
mb();
|
|
ret = lzo1x_1_compress(from_va, PAGE_SIZE, dmem, out_len, wmem);
|
|
BUG_ON(ret != LZO_E_OK);
|
|
*out_va = dmem;
|
|
kunmap_atomic(from_va, KM_USER0);
|
|
ret = 1;
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
|
|
static int zcache_cpu_notifier(struct notifier_block *nb,
|
|
unsigned long action, void *pcpu)
|
|
{
|
|
int cpu = (long)pcpu;
|
|
struct zcache_preload *kp;
|
|
|
|
switch (action) {
|
|
case CPU_UP_PREPARE:
|
|
per_cpu(zcache_dstmem, cpu) = (void *)__get_free_pages(
|
|
GFP_KERNEL | __GFP_REPEAT,
|
|
LZO_DSTMEM_PAGE_ORDER),
|
|
per_cpu(zcache_workmem, cpu) =
|
|
kzalloc(LZO1X_MEM_COMPRESS,
|
|
GFP_KERNEL | __GFP_REPEAT);
|
|
break;
|
|
case CPU_DEAD:
|
|
case CPU_UP_CANCELED:
|
|
free_pages((unsigned long)per_cpu(zcache_dstmem, cpu),
|
|
LZO_DSTMEM_PAGE_ORDER);
|
|
per_cpu(zcache_dstmem, cpu) = NULL;
|
|
kfree(per_cpu(zcache_workmem, cpu));
|
|
per_cpu(zcache_workmem, cpu) = NULL;
|
|
kp = &per_cpu(zcache_preloads, cpu);
|
|
while (kp->nr) {
|
|
kmem_cache_free(zcache_objnode_cache,
|
|
kp->objnodes[kp->nr - 1]);
|
|
kp->objnodes[kp->nr - 1] = NULL;
|
|
kp->nr--;
|
|
}
|
|
if (kp->obj) {
|
|
kmem_cache_free(zcache_obj_cache, kp->obj);
|
|
kp->obj = NULL;
|
|
}
|
|
if (kp->page) {
|
|
free_page((unsigned long)kp->page);
|
|
kp->page = NULL;
|
|
}
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
return NOTIFY_OK;
|
|
}
|
|
|
|
static struct notifier_block zcache_cpu_notifier_block = {
|
|
.notifier_call = zcache_cpu_notifier
|
|
};
|
|
|
|
#ifdef CONFIG_SYSFS
|
|
#define ZCACHE_SYSFS_RO(_name) \
|
|
static ssize_t zcache_##_name##_show(struct kobject *kobj, \
|
|
struct kobj_attribute *attr, char *buf) \
|
|
{ \
|
|
return sprintf(buf, "%lu\n", zcache_##_name); \
|
|
} \
|
|
static struct kobj_attribute zcache_##_name##_attr = { \
|
|
.attr = { .name = __stringify(_name), .mode = 0444 }, \
|
|
.show = zcache_##_name##_show, \
|
|
}
|
|
|
|
#define ZCACHE_SYSFS_RO_ATOMIC(_name) \
|
|
static ssize_t zcache_##_name##_show(struct kobject *kobj, \
|
|
struct kobj_attribute *attr, char *buf) \
|
|
{ \
|
|
return sprintf(buf, "%d\n", atomic_read(&zcache_##_name)); \
|
|
} \
|
|
static struct kobj_attribute zcache_##_name##_attr = { \
|
|
.attr = { .name = __stringify(_name), .mode = 0444 }, \
|
|
.show = zcache_##_name##_show, \
|
|
}
|
|
|
|
#define ZCACHE_SYSFS_RO_CUSTOM(_name, _func) \
|
|
static ssize_t zcache_##_name##_show(struct kobject *kobj, \
|
|
struct kobj_attribute *attr, char *buf) \
|
|
{ \
|
|
return _func(buf); \
|
|
} \
|
|
static struct kobj_attribute zcache_##_name##_attr = { \
|
|
.attr = { .name = __stringify(_name), .mode = 0444 }, \
|
|
.show = zcache_##_name##_show, \
|
|
}
|
|
|
|
ZCACHE_SYSFS_RO(curr_obj_count_max);
|
|
ZCACHE_SYSFS_RO(curr_objnode_count_max);
|
|
ZCACHE_SYSFS_RO(flush_total);
|
|
ZCACHE_SYSFS_RO(flush_found);
|
|
ZCACHE_SYSFS_RO(flobj_total);
|
|
ZCACHE_SYSFS_RO(flobj_found);
|
|
ZCACHE_SYSFS_RO(failed_eph_puts);
|
|
ZCACHE_SYSFS_RO(failed_pers_puts);
|
|
ZCACHE_SYSFS_RO(zbud_curr_zbytes);
|
|
ZCACHE_SYSFS_RO(zbud_cumul_zpages);
|
|
ZCACHE_SYSFS_RO(zbud_cumul_zbytes);
|
|
ZCACHE_SYSFS_RO(zbud_buddied_count);
|
|
ZCACHE_SYSFS_RO(zbpg_unused_list_count);
|
|
ZCACHE_SYSFS_RO(evicted_raw_pages);
|
|
ZCACHE_SYSFS_RO(evicted_unbuddied_pages);
|
|
ZCACHE_SYSFS_RO(evicted_buddied_pages);
|
|
ZCACHE_SYSFS_RO(failed_get_free_pages);
|
|
ZCACHE_SYSFS_RO(failed_alloc);
|
|
ZCACHE_SYSFS_RO(put_to_flush);
|
|
ZCACHE_SYSFS_RO(compress_poor);
|
|
ZCACHE_SYSFS_RO(mean_compress_poor);
|
|
ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_raw_pages);
|
|
ZCACHE_SYSFS_RO_ATOMIC(zbud_curr_zpages);
|
|
ZCACHE_SYSFS_RO_ATOMIC(curr_obj_count);
|
|
ZCACHE_SYSFS_RO_ATOMIC(curr_objnode_count);
|
|
ZCACHE_SYSFS_RO_CUSTOM(zbud_unbuddied_list_counts,
|
|
zbud_show_unbuddied_list_counts);
|
|
ZCACHE_SYSFS_RO_CUSTOM(zbud_cumul_chunk_counts,
|
|
zbud_show_cumul_chunk_counts);
|
|
ZCACHE_SYSFS_RO_CUSTOM(zv_curr_dist_counts,
|
|
zv_curr_dist_counts_show);
|
|
ZCACHE_SYSFS_RO_CUSTOM(zv_cumul_dist_counts,
|
|
zv_cumul_dist_counts_show);
|
|
|
|
static struct attribute *zcache_attrs[] = {
|
|
&zcache_curr_obj_count_attr.attr,
|
|
&zcache_curr_obj_count_max_attr.attr,
|
|
&zcache_curr_objnode_count_attr.attr,
|
|
&zcache_curr_objnode_count_max_attr.attr,
|
|
&zcache_flush_total_attr.attr,
|
|
&zcache_flobj_total_attr.attr,
|
|
&zcache_flush_found_attr.attr,
|
|
&zcache_flobj_found_attr.attr,
|
|
&zcache_failed_eph_puts_attr.attr,
|
|
&zcache_failed_pers_puts_attr.attr,
|
|
&zcache_compress_poor_attr.attr,
|
|
&zcache_mean_compress_poor_attr.attr,
|
|
&zcache_zbud_curr_raw_pages_attr.attr,
|
|
&zcache_zbud_curr_zpages_attr.attr,
|
|
&zcache_zbud_curr_zbytes_attr.attr,
|
|
&zcache_zbud_cumul_zpages_attr.attr,
|
|
&zcache_zbud_cumul_zbytes_attr.attr,
|
|
&zcache_zbud_buddied_count_attr.attr,
|
|
&zcache_zbpg_unused_list_count_attr.attr,
|
|
&zcache_evicted_raw_pages_attr.attr,
|
|
&zcache_evicted_unbuddied_pages_attr.attr,
|
|
&zcache_evicted_buddied_pages_attr.attr,
|
|
&zcache_failed_get_free_pages_attr.attr,
|
|
&zcache_failed_alloc_attr.attr,
|
|
&zcache_put_to_flush_attr.attr,
|
|
&zcache_zbud_unbuddied_list_counts_attr.attr,
|
|
&zcache_zbud_cumul_chunk_counts_attr.attr,
|
|
&zcache_zv_curr_dist_counts_attr.attr,
|
|
&zcache_zv_cumul_dist_counts_attr.attr,
|
|
&zcache_zv_max_zsize_attr.attr,
|
|
&zcache_zv_max_mean_zsize_attr.attr,
|
|
&zcache_zv_page_count_policy_percent_attr.attr,
|
|
NULL,
|
|
};
|
|
|
|
static struct attribute_group zcache_attr_group = {
|
|
.attrs = zcache_attrs,
|
|
.name = "zcache",
|
|
};
|
|
|
|
#endif /* CONFIG_SYSFS */
|
|
/*
|
|
* When zcache is disabled ("frozen"), pools can be created and destroyed,
|
|
* but all puts (and thus all other operations that require memory allocation)
|
|
* must fail. If zcache is unfrozen, accepts puts, then frozen again,
|
|
* data consistency requires all puts while frozen to be converted into
|
|
* flushes.
|
|
*/
|
|
static bool zcache_freeze;
|
|
|
|
/*
|
|
* zcache shrinker interface (only useful for ephemeral pages, so zbud only)
|
|
*/
|
|
static int shrink_zcache_memory(struct shrinker *shrink,
|
|
struct shrink_control *sc)
|
|
{
|
|
int ret = -1;
|
|
int nr = sc->nr_to_scan;
|
|
gfp_t gfp_mask = sc->gfp_mask;
|
|
|
|
if (nr >= 0) {
|
|
if (!(gfp_mask & __GFP_FS))
|
|
/* does this case really need to be skipped? */
|
|
goto out;
|
|
zbud_evict_pages(nr);
|
|
}
|
|
ret = (int)atomic_read(&zcache_zbud_curr_raw_pages);
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
static struct shrinker zcache_shrinker = {
|
|
.shrink = shrink_zcache_memory,
|
|
.seeks = DEFAULT_SEEKS,
|
|
};
|
|
|
|
/*
|
|
* zcache shims between cleancache/frontswap ops and tmem
|
|
*/
|
|
|
|
static int zcache_put_page(int cli_id, int pool_id, struct tmem_oid *oidp,
|
|
uint32_t index, struct page *page)
|
|
{
|
|
struct tmem_pool *pool;
|
|
int ret = -1;
|
|
|
|
BUG_ON(!irqs_disabled());
|
|
pool = zcache_get_pool_by_id(cli_id, pool_id);
|
|
if (unlikely(pool == NULL))
|
|
goto out;
|
|
if (!zcache_freeze && zcache_do_preload(pool) == 0) {
|
|
/* preload does preempt_disable on success */
|
|
ret = tmem_put(pool, oidp, index, (char *)(page),
|
|
PAGE_SIZE, 0, is_ephemeral(pool));
|
|
if (ret < 0) {
|
|
if (is_ephemeral(pool))
|
|
zcache_failed_eph_puts++;
|
|
else
|
|
zcache_failed_pers_puts++;
|
|
}
|
|
zcache_put_pool(pool);
|
|
preempt_enable_no_resched();
|
|
} else {
|
|
zcache_put_to_flush++;
|
|
if (atomic_read(&pool->obj_count) > 0)
|
|
/* the put fails whether the flush succeeds or not */
|
|
(void)tmem_flush_page(pool, oidp, index);
|
|
zcache_put_pool(pool);
|
|
}
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
static int zcache_get_page(int cli_id, int pool_id, struct tmem_oid *oidp,
|
|
uint32_t index, struct page *page)
|
|
{
|
|
struct tmem_pool *pool;
|
|
int ret = -1;
|
|
unsigned long flags;
|
|
size_t size = PAGE_SIZE;
|
|
|
|
local_irq_save(flags);
|
|
pool = zcache_get_pool_by_id(cli_id, pool_id);
|
|
if (likely(pool != NULL)) {
|
|
if (atomic_read(&pool->obj_count) > 0)
|
|
ret = tmem_get(pool, oidp, index, (char *)(page),
|
|
&size, 0, is_ephemeral(pool));
|
|
zcache_put_pool(pool);
|
|
}
|
|
local_irq_restore(flags);
|
|
return ret;
|
|
}
|
|
|
|
static int zcache_flush_page(int cli_id, int pool_id,
|
|
struct tmem_oid *oidp, uint32_t index)
|
|
{
|
|
struct tmem_pool *pool;
|
|
int ret = -1;
|
|
unsigned long flags;
|
|
|
|
local_irq_save(flags);
|
|
zcache_flush_total++;
|
|
pool = zcache_get_pool_by_id(cli_id, pool_id);
|
|
if (likely(pool != NULL)) {
|
|
if (atomic_read(&pool->obj_count) > 0)
|
|
ret = tmem_flush_page(pool, oidp, index);
|
|
zcache_put_pool(pool);
|
|
}
|
|
if (ret >= 0)
|
|
zcache_flush_found++;
|
|
local_irq_restore(flags);
|
|
return ret;
|
|
}
|
|
|
|
static int zcache_flush_object(int cli_id, int pool_id,
|
|
struct tmem_oid *oidp)
|
|
{
|
|
struct tmem_pool *pool;
|
|
int ret = -1;
|
|
unsigned long flags;
|
|
|
|
local_irq_save(flags);
|
|
zcache_flobj_total++;
|
|
pool = zcache_get_pool_by_id(cli_id, pool_id);
|
|
if (likely(pool != NULL)) {
|
|
if (atomic_read(&pool->obj_count) > 0)
|
|
ret = tmem_flush_object(pool, oidp);
|
|
zcache_put_pool(pool);
|
|
}
|
|
if (ret >= 0)
|
|
zcache_flobj_found++;
|
|
local_irq_restore(flags);
|
|
return ret;
|
|
}
|
|
|
|
static int zcache_destroy_pool(int cli_id, int pool_id)
|
|
{
|
|
struct tmem_pool *pool = NULL;
|
|
struct zcache_client *cli = NULL;
|
|
int ret = -1;
|
|
|
|
if (pool_id < 0)
|
|
goto out;
|
|
if (cli_id == LOCAL_CLIENT)
|
|
cli = &zcache_host;
|
|
else if ((unsigned int)cli_id < MAX_CLIENTS)
|
|
cli = &zcache_clients[cli_id];
|
|
if (cli == NULL)
|
|
goto out;
|
|
atomic_inc(&cli->refcount);
|
|
pool = cli->tmem_pools[pool_id];
|
|
if (pool == NULL)
|
|
goto out;
|
|
cli->tmem_pools[pool_id] = NULL;
|
|
/* wait for pool activity on other cpus to quiesce */
|
|
while (atomic_read(&pool->refcount) != 0)
|
|
;
|
|
atomic_dec(&cli->refcount);
|
|
local_bh_disable();
|
|
ret = tmem_destroy_pool(pool);
|
|
local_bh_enable();
|
|
kfree(pool);
|
|
pr_info("zcache: destroyed pool id=%d, cli_id=%d\n",
|
|
pool_id, cli_id);
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
static int zcache_new_pool(uint16_t cli_id, uint32_t flags)
|
|
{
|
|
int poolid = -1;
|
|
struct tmem_pool *pool;
|
|
struct zcache_client *cli = NULL;
|
|
|
|
if (cli_id == LOCAL_CLIENT)
|
|
cli = &zcache_host;
|
|
else if ((unsigned int)cli_id < MAX_CLIENTS)
|
|
cli = &zcache_clients[cli_id];
|
|
if (cli == NULL)
|
|
goto out;
|
|
atomic_inc(&cli->refcount);
|
|
pool = kmalloc(sizeof(struct tmem_pool), GFP_ATOMIC);
|
|
if (pool == NULL) {
|
|
pr_info("zcache: pool creation failed: out of memory\n");
|
|
goto out;
|
|
}
|
|
|
|
for (poolid = 0; poolid < MAX_POOLS_PER_CLIENT; poolid++)
|
|
if (cli->tmem_pools[poolid] == NULL)
|
|
break;
|
|
if (poolid >= MAX_POOLS_PER_CLIENT) {
|
|
pr_info("zcache: pool creation failed: max exceeded\n");
|
|
kfree(pool);
|
|
poolid = -1;
|
|
goto out;
|
|
}
|
|
atomic_set(&pool->refcount, 0);
|
|
pool->client = cli;
|
|
pool->pool_id = poolid;
|
|
tmem_new_pool(pool, flags);
|
|
cli->tmem_pools[poolid] = pool;
|
|
pr_info("zcache: created %s tmem pool, id=%d, client=%d\n",
|
|
flags & TMEM_POOL_PERSIST ? "persistent" : "ephemeral",
|
|
poolid, cli_id);
|
|
out:
|
|
if (cli != NULL)
|
|
atomic_dec(&cli->refcount);
|
|
return poolid;
|
|
}
|
|
|
|
/**********
|
|
* Two kernel functionalities currently can be layered on top of tmem.
|
|
* These are "cleancache" which is used as a second-chance cache for clean
|
|
* page cache pages; and "frontswap" which is used for swap pages
|
|
* to avoid writes to disk. A generic "shim" is provided here for each
|
|
* to translate in-kernel semantics to zcache semantics.
|
|
*/
|
|
|
|
#ifdef CONFIG_CLEANCACHE
|
|
static void zcache_cleancache_put_page(int pool_id,
|
|
struct cleancache_filekey key,
|
|
pgoff_t index, struct page *page)
|
|
{
|
|
u32 ind = (u32) index;
|
|
struct tmem_oid oid = *(struct tmem_oid *)&key;
|
|
|
|
if (likely(ind == index))
|
|
(void)zcache_put_page(LOCAL_CLIENT, pool_id, &oid, index, page);
|
|
}
|
|
|
|
static int zcache_cleancache_get_page(int pool_id,
|
|
struct cleancache_filekey key,
|
|
pgoff_t index, struct page *page)
|
|
{
|
|
u32 ind = (u32) index;
|
|
struct tmem_oid oid = *(struct tmem_oid *)&key;
|
|
int ret = -1;
|
|
|
|
if (likely(ind == index))
|
|
ret = zcache_get_page(LOCAL_CLIENT, pool_id, &oid, index, page);
|
|
return ret;
|
|
}
|
|
|
|
static void zcache_cleancache_flush_page(int pool_id,
|
|
struct cleancache_filekey key,
|
|
pgoff_t index)
|
|
{
|
|
u32 ind = (u32) index;
|
|
struct tmem_oid oid = *(struct tmem_oid *)&key;
|
|
|
|
if (likely(ind == index))
|
|
(void)zcache_flush_page(LOCAL_CLIENT, pool_id, &oid, ind);
|
|
}
|
|
|
|
static void zcache_cleancache_flush_inode(int pool_id,
|
|
struct cleancache_filekey key)
|
|
{
|
|
struct tmem_oid oid = *(struct tmem_oid *)&key;
|
|
|
|
(void)zcache_flush_object(LOCAL_CLIENT, pool_id, &oid);
|
|
}
|
|
|
|
static void zcache_cleancache_flush_fs(int pool_id)
|
|
{
|
|
if (pool_id >= 0)
|
|
(void)zcache_destroy_pool(LOCAL_CLIENT, pool_id);
|
|
}
|
|
|
|
static int zcache_cleancache_init_fs(size_t pagesize)
|
|
{
|
|
BUG_ON(sizeof(struct cleancache_filekey) !=
|
|
sizeof(struct tmem_oid));
|
|
BUG_ON(pagesize != PAGE_SIZE);
|
|
return zcache_new_pool(LOCAL_CLIENT, 0);
|
|
}
|
|
|
|
static int zcache_cleancache_init_shared_fs(char *uuid, size_t pagesize)
|
|
{
|
|
/* shared pools are unsupported and map to private */
|
|
BUG_ON(sizeof(struct cleancache_filekey) !=
|
|
sizeof(struct tmem_oid));
|
|
BUG_ON(pagesize != PAGE_SIZE);
|
|
return zcache_new_pool(LOCAL_CLIENT, 0);
|
|
}
|
|
|
|
static struct cleancache_ops zcache_cleancache_ops = {
|
|
.put_page = zcache_cleancache_put_page,
|
|
.get_page = zcache_cleancache_get_page,
|
|
.flush_page = zcache_cleancache_flush_page,
|
|
.flush_inode = zcache_cleancache_flush_inode,
|
|
.flush_fs = zcache_cleancache_flush_fs,
|
|
.init_shared_fs = zcache_cleancache_init_shared_fs,
|
|
.init_fs = zcache_cleancache_init_fs
|
|
};
|
|
|
|
struct cleancache_ops zcache_cleancache_register_ops(void)
|
|
{
|
|
struct cleancache_ops old_ops =
|
|
cleancache_register_ops(&zcache_cleancache_ops);
|
|
|
|
return old_ops;
|
|
}
|
|
#endif
|
|
|
|
#ifdef CONFIG_FRONTSWAP
|
|
/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
|
|
static int zcache_frontswap_poolid = -1;
|
|
|
|
/*
|
|
* Swizzling increases objects per swaptype, increasing tmem concurrency
|
|
* for heavy swaploads. Later, larger nr_cpus -> larger SWIZ_BITS
|
|
* Setting SWIZ_BITS to 27 basically reconstructs the swap entry from
|
|
* frontswap_get_page(), but has side-effects. Hence using 8.
|
|
*/
|
|
#define SWIZ_BITS 8
|
|
#define SWIZ_MASK ((1 << SWIZ_BITS) - 1)
|
|
#define _oswiz(_type, _ind) ((_type << SWIZ_BITS) | (_ind & SWIZ_MASK))
|
|
#define iswiz(_ind) (_ind >> SWIZ_BITS)
|
|
|
|
static inline struct tmem_oid oswiz(unsigned type, u32 ind)
|
|
{
|
|
struct tmem_oid oid = { .oid = { 0 } };
|
|
oid.oid[0] = _oswiz(type, ind);
|
|
return oid;
|
|
}
|
|
|
|
static int zcache_frontswap_put_page(unsigned type, pgoff_t offset,
|
|
struct page *page)
|
|
{
|
|
u64 ind64 = (u64)offset;
|
|
u32 ind = (u32)offset;
|
|
struct tmem_oid oid = oswiz(type, ind);
|
|
int ret = -1;
|
|
unsigned long flags;
|
|
|
|
BUG_ON(!PageLocked(page));
|
|
if (likely(ind64 == ind)) {
|
|
local_irq_save(flags);
|
|
ret = zcache_put_page(LOCAL_CLIENT, zcache_frontswap_poolid,
|
|
&oid, iswiz(ind), page);
|
|
local_irq_restore(flags);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/* returns 0 if the page was successfully gotten from frontswap, -1 if
|
|
* was not present (should never happen!) */
|
|
static int zcache_frontswap_get_page(unsigned type, pgoff_t offset,
|
|
struct page *page)
|
|
{
|
|
u64 ind64 = (u64)offset;
|
|
u32 ind = (u32)offset;
|
|
struct tmem_oid oid = oswiz(type, ind);
|
|
int ret = -1;
|
|
|
|
BUG_ON(!PageLocked(page));
|
|
if (likely(ind64 == ind))
|
|
ret = zcache_get_page(LOCAL_CLIENT, zcache_frontswap_poolid,
|
|
&oid, iswiz(ind), page);
|
|
return ret;
|
|
}
|
|
|
|
/* flush a single page from frontswap */
|
|
static void zcache_frontswap_flush_page(unsigned type, pgoff_t offset)
|
|
{
|
|
u64 ind64 = (u64)offset;
|
|
u32 ind = (u32)offset;
|
|
struct tmem_oid oid = oswiz(type, ind);
|
|
|
|
if (likely(ind64 == ind))
|
|
(void)zcache_flush_page(LOCAL_CLIENT, zcache_frontswap_poolid,
|
|
&oid, iswiz(ind));
|
|
}
|
|
|
|
/* flush all pages from the passed swaptype */
|
|
static void zcache_frontswap_flush_area(unsigned type)
|
|
{
|
|
struct tmem_oid oid;
|
|
int ind;
|
|
|
|
for (ind = SWIZ_MASK; ind >= 0; ind--) {
|
|
oid = oswiz(type, ind);
|
|
(void)zcache_flush_object(LOCAL_CLIENT,
|
|
zcache_frontswap_poolid, &oid);
|
|
}
|
|
}
|
|
|
|
static void zcache_frontswap_init(unsigned ignored)
|
|
{
|
|
/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
|
|
if (zcache_frontswap_poolid < 0)
|
|
zcache_frontswap_poolid =
|
|
zcache_new_pool(LOCAL_CLIENT, TMEM_POOL_PERSIST);
|
|
}
|
|
|
|
static struct frontswap_ops zcache_frontswap_ops = {
|
|
.put_page = zcache_frontswap_put_page,
|
|
.get_page = zcache_frontswap_get_page,
|
|
.flush_page = zcache_frontswap_flush_page,
|
|
.flush_area = zcache_frontswap_flush_area,
|
|
.init = zcache_frontswap_init
|
|
};
|
|
|
|
struct frontswap_ops zcache_frontswap_register_ops(void)
|
|
{
|
|
struct frontswap_ops old_ops =
|
|
frontswap_register_ops(&zcache_frontswap_ops);
|
|
|
|
return old_ops;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* zcache initialization
|
|
* NOTE FOR NOW zcache MUST BE PROVIDED AS A KERNEL BOOT PARAMETER OR
|
|
* NOTHING HAPPENS!
|
|
*/
|
|
|
|
static int zcache_enabled;
|
|
|
|
static int __init enable_zcache(char *s)
|
|
{
|
|
zcache_enabled = 1;
|
|
return 1;
|
|
}
|
|
__setup("zcache", enable_zcache);
|
|
|
|
/* allow independent dynamic disabling of cleancache and frontswap */
|
|
|
|
static int use_cleancache = 1;
|
|
|
|
static int __init no_cleancache(char *s)
|
|
{
|
|
use_cleancache = 0;
|
|
return 1;
|
|
}
|
|
|
|
__setup("nocleancache", no_cleancache);
|
|
|
|
static int use_frontswap = 1;
|
|
|
|
static int __init no_frontswap(char *s)
|
|
{
|
|
use_frontswap = 0;
|
|
return 1;
|
|
}
|
|
|
|
__setup("nofrontswap", no_frontswap);
|
|
|
|
static int __init zcache_init(void)
|
|
{
|
|
int ret = 0;
|
|
|
|
#ifdef CONFIG_SYSFS
|
|
ret = sysfs_create_group(mm_kobj, &zcache_attr_group);
|
|
if (ret) {
|
|
pr_err("zcache: can't create sysfs\n");
|
|
goto out;
|
|
}
|
|
#endif /* CONFIG_SYSFS */
|
|
#if defined(CONFIG_CLEANCACHE) || defined(CONFIG_FRONTSWAP)
|
|
if (zcache_enabled) {
|
|
unsigned int cpu;
|
|
|
|
tmem_register_hostops(&zcache_hostops);
|
|
tmem_register_pamops(&zcache_pamops);
|
|
ret = register_cpu_notifier(&zcache_cpu_notifier_block);
|
|
if (ret) {
|
|
pr_err("zcache: can't register cpu notifier\n");
|
|
goto out;
|
|
}
|
|
for_each_online_cpu(cpu) {
|
|
void *pcpu = (void *)(long)cpu;
|
|
zcache_cpu_notifier(&zcache_cpu_notifier_block,
|
|
CPU_UP_PREPARE, pcpu);
|
|
}
|
|
}
|
|
zcache_objnode_cache = kmem_cache_create("zcache_objnode",
|
|
sizeof(struct tmem_objnode), 0, 0, NULL);
|
|
zcache_obj_cache = kmem_cache_create("zcache_obj",
|
|
sizeof(struct tmem_obj), 0, 0, NULL);
|
|
ret = zcache_new_client(LOCAL_CLIENT);
|
|
if (ret) {
|
|
pr_err("zcache: can't create client\n");
|
|
goto out;
|
|
}
|
|
#endif
|
|
#ifdef CONFIG_CLEANCACHE
|
|
if (zcache_enabled && use_cleancache) {
|
|
struct cleancache_ops old_ops;
|
|
|
|
zbud_init();
|
|
register_shrinker(&zcache_shrinker);
|
|
old_ops = zcache_cleancache_register_ops();
|
|
pr_info("zcache: cleancache enabled using kernel "
|
|
"transcendent memory and compression buddies\n");
|
|
if (old_ops.init_fs != NULL)
|
|
pr_warning("zcache: cleancache_ops overridden");
|
|
}
|
|
#endif
|
|
#ifdef CONFIG_FRONTSWAP
|
|
if (zcache_enabled && use_frontswap) {
|
|
struct frontswap_ops old_ops;
|
|
|
|
old_ops = zcache_frontswap_register_ops();
|
|
pr_info("zcache: frontswap enabled using kernel "
|
|
"transcendent memory and xvmalloc\n");
|
|
if (old_ops.init != NULL)
|
|
pr_warning("zcache: frontswap_ops overridden");
|
|
}
|
|
#endif
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
module_init(zcache_init)
|