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linux/arch/sparc64/kernel/sys_sparc.c
Wolfgang Wander 1363c3cd86 [PATCH] Avoiding mmap fragmentation 
Ingo recently introduced a great speedup for allocating new mmaps using the
free_area_cache pointer which boosts the specweb SSL benchmark by 4-5% and
causes huge performance increases in thread creation.

The downside of this patch is that it does lead to fragmentation in the
mmap-ed areas (visible via /proc/self/maps), such that some applications
that work fine under 2.4 kernels quickly run out of memory on any 2.6
kernel.

The problem is twofold:

  1) the free_area_cache is used to continue a search for memory where
     the last search ended.  Before the change new areas were always
     searched from the base address on.

     So now new small areas are cluttering holes of all sizes
     throughout the whole mmap-able region whereas before small holes
     tended to close holes near the base leaving holes far from the base
     large and available for larger requests.

  2) the free_area_cache also is set to the location of the last
     munmap-ed area so in scenarios where we allocate e.g.  five regions of
     1K each, then free regions 4 2 3 in this order the next request for 1K
     will be placed in the position of the old region 3, whereas before we
     appended it to the still active region 1, placing it at the location
     of the old region 2.  Before we had 1 free region of 2K, now we only
     get two free regions of 1K -> fragmentation.

The patch addresses thes issues by introducing yet another cache descriptor
cached_hole_size that contains the largest known hole size below the
current free_area_cache.  If a new request comes in the size is compared
against the cached_hole_size and if the request can be filled with a hole
below free_area_cache the search is started from the base instead.

The results look promising: Whereas 2.6.12-rc4 fragments quickly and my
(earlier posted) leakme.c test program terminates after 50000+ iterations
with 96 distinct and fragmented maps in /proc/self/maps it performs nicely
(as expected) with thread creation, Ingo's test_str02 with 20000 threads
requires 0.7s system time.

Taking out Ingo's patch (un-patch available per request) by basically
deleting all mentions of free_area_cache from the kernel and starting the
search for new memory always at the respective bases we observe: leakme
terminates successfully with 11 distinctive hardly fragmented areas in
/proc/self/maps but thread creating is gringdingly slow: 30+s(!) system
time for Ingo's test_str02 with 20000 threads.

Now - drumroll ;-) the appended patch works fine with leakme: it ends with
only 7 distinct areas in /proc/self/maps and also thread creation seems
sufficiently fast with 0.71s for 20000 threads.

Signed-off-by: Wolfgang Wander <wwc@rentec.com>
Credit-to: "Richard Purdie" <rpurdie@rpsys.net>
Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu> (partly)
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-21 18:46:16 -07:00

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/* $Id: sys_sparc.c,v 1.57 2002/02/09 19:49:30 davem Exp $
* linux/arch/sparc64/kernel/sys_sparc.c
*
* This file contains various random system calls that
* have a non-standard calling sequence on the Linux/sparc
* platform.
*/
#include <linux/config.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/sem.h>
#include <linux/msg.h>
#include <linux/shm.h>
#include <linux/stat.h>
#include <linux/mman.h>
#include <linux/utsname.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/slab.h>
#include <linux/syscalls.h>
#include <linux/ipc.h>
#include <linux/personality.h>
#include <asm/uaccess.h>
#include <asm/ipc.h>
#include <asm/utrap.h>
#include <asm/perfctr.h>
/* #define DEBUG_UNIMP_SYSCALL */
/* XXX Make this per-binary type, this way we can detect the type of
* XXX a binary. Every Sparc executable calls this very early on.
*/
asmlinkage unsigned long sys_getpagesize(void)
{
return PAGE_SIZE;
}
#define COLOUR_ALIGN(addr,pgoff) \
((((addr)+SHMLBA-1)&~(SHMLBA-1)) + \
(((pgoff)<<PAGE_SHIFT) & (SHMLBA-1)))
unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags)
{
struct mm_struct *mm = current->mm;
struct vm_area_struct * vma;
unsigned long task_size = TASK_SIZE;
unsigned long start_addr;
int do_color_align;
if (flags & MAP_FIXED) {
/* We do not accept a shared mapping if it would violate
* cache aliasing constraints.
*/
if ((flags & MAP_SHARED) &&
((addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1)))
return -EINVAL;
return addr;
}
if (test_thread_flag(TIF_32BIT))
task_size = 0xf0000000UL;
if (len > task_size || len > -PAGE_OFFSET)
return -ENOMEM;
do_color_align = 0;
if (filp || (flags & MAP_SHARED))
do_color_align = 1;
if (addr) {
if (do_color_align)
addr = COLOUR_ALIGN(addr, pgoff);
else
addr = PAGE_ALIGN(addr);
vma = find_vma(mm, addr);
if (task_size - len >= addr &&
(!vma || addr + len <= vma->vm_start))
return addr;
}
if (len <= mm->cached_hole_size) {
mm->cached_hole_size = 0;
mm->free_area_cache = TASK_UNMAPPED_BASE;
}
start_addr = addr = mm->free_area_cache;
task_size -= len;
full_search:
if (do_color_align)
addr = COLOUR_ALIGN(addr, pgoff);
else
addr = PAGE_ALIGN(addr);
for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
/* At this point: (!vma || addr < vma->vm_end). */
if (addr < PAGE_OFFSET && -PAGE_OFFSET - len < addr) {
addr = PAGE_OFFSET;
vma = find_vma(mm, PAGE_OFFSET);
}
if (task_size < addr) {
if (start_addr != TASK_UNMAPPED_BASE) {
start_addr = addr = TASK_UNMAPPED_BASE;
mm->cached_hole_size = 0;
goto full_search;
}
return -ENOMEM;
}
if (!vma || addr + len <= vma->vm_start) {
/*
* Remember the place where we stopped the search:
*/
mm->free_area_cache = addr + len;
return addr;
}
if (addr + mm->cached_hole_size < vma->vm_start)
mm->cached_hole_size = vma->vm_start - addr;
addr = vma->vm_end;
if (do_color_align)
addr = COLOUR_ALIGN(addr, pgoff);
}
}
/* Try to align mapping such that we align it as much as possible. */
unsigned long get_fb_unmapped_area(struct file *filp, unsigned long orig_addr, unsigned long len, unsigned long pgoff, unsigned long flags)
{
unsigned long align_goal, addr = -ENOMEM;
if (flags & MAP_FIXED) {
/* Ok, don't mess with it. */
return get_unmapped_area(NULL, addr, len, pgoff, flags);
}
flags &= ~MAP_SHARED;
align_goal = PAGE_SIZE;
if (len >= (4UL * 1024 * 1024))
align_goal = (4UL * 1024 * 1024);
else if (len >= (512UL * 1024))
align_goal = (512UL * 1024);
else if (len >= (64UL * 1024))
align_goal = (64UL * 1024);
do {
addr = get_unmapped_area(NULL, orig_addr, len + (align_goal - PAGE_SIZE), pgoff, flags);
if (!(addr & ~PAGE_MASK)) {
addr = (addr + (align_goal - 1UL)) & ~(align_goal - 1UL);
break;
}
if (align_goal == (4UL * 1024 * 1024))
align_goal = (512UL * 1024);
else if (align_goal == (512UL * 1024))
align_goal = (64UL * 1024);
else
align_goal = PAGE_SIZE;
} while ((addr & ~PAGE_MASK) && align_goal > PAGE_SIZE);
/* Mapping is smaller than 64K or larger areas could not
* be obtained.
*/
if (addr & ~PAGE_MASK)
addr = get_unmapped_area(NULL, orig_addr, len, pgoff, flags);
return addr;
}
asmlinkage unsigned long sparc_brk(unsigned long brk)
{
/* People could try to be nasty and use ta 0x6d in 32bit programs */
if (test_thread_flag(TIF_32BIT) &&
brk >= 0xf0000000UL)
return current->mm->brk;
if ((current->mm->brk & PAGE_OFFSET) != (brk & PAGE_OFFSET))
return current->mm->brk;
return sys_brk(brk);
}
/*
* sys_pipe() is the normal C calling standard for creating
* a pipe. It's not the way unix traditionally does this, though.
*/
asmlinkage long sparc_pipe(struct pt_regs *regs)
{
int fd[2];
int error;
error = do_pipe(fd);
if (error)
goto out;
regs->u_regs[UREG_I1] = fd[1];
error = fd[0];
out:
return error;
}
/*
* sys_ipc() is the de-multiplexer for the SysV IPC calls..
*
* This is really horribly ugly.
*/
asmlinkage long sys_ipc(unsigned int call, int first, unsigned long second,
unsigned long third, void __user *ptr, long fifth)
{
int err;
/* No need for backward compatibility. We can start fresh... */
if (call <= SEMCTL) {
switch (call) {
case SEMOP:
err = sys_semtimedop(first, ptr,
(unsigned)second, NULL);
goto out;
case SEMTIMEDOP:
err = sys_semtimedop(first, ptr, (unsigned)second,
(const struct timespec __user *) fifth);
goto out;
case SEMGET:
err = sys_semget(first, (int)second, (int)third);
goto out;
case SEMCTL: {
union semun fourth;
err = -EINVAL;
if (!ptr)
goto out;
err = -EFAULT;
if (get_user(fourth.__pad,
(void __user * __user *) ptr))
goto out;
err = sys_semctl(first, (int)second | IPC_64,
(int)third, fourth);
goto out;
}
default:
err = -ENOSYS;
goto out;
};
}
if (call <= MSGCTL) {
switch (call) {
case MSGSND:
err = sys_msgsnd(first, ptr, (size_t)second,
(int)third);
goto out;
case MSGRCV:
err = sys_msgrcv(first, ptr, (size_t)second, fifth,
(int)third);
goto out;
case MSGGET:
err = sys_msgget((key_t)first, (int)second);
goto out;
case MSGCTL:
err = sys_msgctl(first, (int)second | IPC_64, ptr);
goto out;
default:
err = -ENOSYS;
goto out;
};
}
if (call <= SHMCTL) {
switch (call) {
case SHMAT: {
ulong raddr;
err = do_shmat(first, ptr, (int)second, &raddr);
if (!err) {
if (put_user(raddr,
(ulong __user *) third))
err = -EFAULT;
}
goto out;
}
case SHMDT:
err = sys_shmdt(ptr);
goto out;
case SHMGET:
err = sys_shmget(first, (size_t)second, (int)third);
goto out;
case SHMCTL:
err = sys_shmctl(first, (int)second | IPC_64, ptr);
goto out;
default:
err = -ENOSYS;
goto out;
};
} else {
err = -ENOSYS;
}
out:
return err;
}
asmlinkage long sparc64_newuname(struct new_utsname __user *name)
{
int ret = sys_newuname(name);
if (current->personality == PER_LINUX32 && !ret) {
ret = (copy_to_user(name->machine, "sparc\0\0", 8)
? -EFAULT : 0);
}
return ret;
}
asmlinkage long sparc64_personality(unsigned long personality)
{
int ret;
if (current->personality == PER_LINUX32 &&
personality == PER_LINUX)
personality = PER_LINUX32;
ret = sys_personality(personality);
if (ret == PER_LINUX32)
ret = PER_LINUX;
return ret;
}
/* Linux version of mmap */
asmlinkage unsigned long sys_mmap(unsigned long addr, unsigned long len,
unsigned long prot, unsigned long flags, unsigned long fd,
unsigned long off)
{
struct file * file = NULL;
unsigned long retval = -EBADF;
if (!(flags & MAP_ANONYMOUS)) {
file = fget(fd);
if (!file)
goto out;
}
flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
len = PAGE_ALIGN(len);
retval = -EINVAL;
if (test_thread_flag(TIF_32BIT)) {
if (len > 0xf0000000UL ||
((flags & MAP_FIXED) && addr > 0xf0000000UL - len))
goto out_putf;
} else {
if (len > -PAGE_OFFSET ||
((flags & MAP_FIXED) &&
addr < PAGE_OFFSET && addr + len > -PAGE_OFFSET))
goto out_putf;
}
down_write(&current->mm->mmap_sem);
retval = do_mmap(file, addr, len, prot, flags, off);
up_write(&current->mm->mmap_sem);
out_putf:
if (file)
fput(file);
out:
return retval;
}
asmlinkage long sys64_munmap(unsigned long addr, size_t len)
{
long ret;
if (len > -PAGE_OFFSET ||
(addr < PAGE_OFFSET && addr + len > -PAGE_OFFSET))
return -EINVAL;
down_write(&current->mm->mmap_sem);
ret = do_munmap(current->mm, addr, len);
up_write(&current->mm->mmap_sem);
return ret;
}
extern unsigned long do_mremap(unsigned long addr,
unsigned long old_len, unsigned long new_len,
unsigned long flags, unsigned long new_addr);
asmlinkage unsigned long sys64_mremap(unsigned long addr,
unsigned long old_len, unsigned long new_len,
unsigned long flags, unsigned long new_addr)
{
struct vm_area_struct *vma;
unsigned long ret = -EINVAL;
if (test_thread_flag(TIF_32BIT))
goto out;
if (old_len > -PAGE_OFFSET || new_len > -PAGE_OFFSET)
goto out;
if (addr < PAGE_OFFSET && addr + old_len > -PAGE_OFFSET)
goto out;
down_write(&current->mm->mmap_sem);
if (flags & MREMAP_FIXED) {
if (new_addr < PAGE_OFFSET &&
new_addr + new_len > -PAGE_OFFSET)
goto out_sem;
} else if (addr < PAGE_OFFSET && addr + new_len > -PAGE_OFFSET) {
unsigned long map_flags = 0;
struct file *file = NULL;
ret = -ENOMEM;
if (!(flags & MREMAP_MAYMOVE))
goto out_sem;
vma = find_vma(current->mm, addr);
if (vma) {
if (vma->vm_flags & VM_SHARED)
map_flags |= MAP_SHARED;
file = vma->vm_file;
}
/* MREMAP_FIXED checked above. */
new_addr = get_unmapped_area(file, addr, new_len,
vma ? vma->vm_pgoff : 0,
map_flags);
ret = new_addr;
if (new_addr & ~PAGE_MASK)
goto out_sem;
flags |= MREMAP_FIXED;
}
ret = do_mremap(addr, old_len, new_len, flags, new_addr);
out_sem:
up_write(&current->mm->mmap_sem);
out:
return ret;
}
/* we come to here via sys_nis_syscall so it can setup the regs argument */
asmlinkage unsigned long c_sys_nis_syscall(struct pt_regs *regs)
{
static int count;
/* Don't make the system unusable, if someone goes stuck */
if (count++ > 5)
return -ENOSYS;
printk ("Unimplemented SPARC system call %ld\n",regs->u_regs[1]);
#ifdef DEBUG_UNIMP_SYSCALL
show_regs (regs);
#endif
return -ENOSYS;
}
/* #define DEBUG_SPARC_BREAKPOINT */
asmlinkage void sparc_breakpoint(struct pt_regs *regs)
{
siginfo_t info;
if (test_thread_flag(TIF_32BIT)) {
regs->tpc &= 0xffffffff;
regs->tnpc &= 0xffffffff;
}
#ifdef DEBUG_SPARC_BREAKPOINT
printk ("TRAP: Entering kernel PC=%lx, nPC=%lx\n", regs->tpc, regs->tnpc);
#endif
info.si_signo = SIGTRAP;
info.si_errno = 0;
info.si_code = TRAP_BRKPT;
info.si_addr = (void __user *)regs->tpc;
info.si_trapno = 0;
force_sig_info(SIGTRAP, &info, current);
#ifdef DEBUG_SPARC_BREAKPOINT
printk ("TRAP: Returning to space: PC=%lx nPC=%lx\n", regs->tpc, regs->tnpc);
#endif
}
extern void check_pending(int signum);
asmlinkage long sys_getdomainname(char __user *name, int len)
{
int nlen;
int err = -EFAULT;
down_read(&uts_sem);
nlen = strlen(system_utsname.domainname) + 1;
if (nlen < len)
len = nlen;
if (len > __NEW_UTS_LEN)
goto done;
if (copy_to_user(name, system_utsname.domainname, len))
goto done;
err = 0;
done:
up_read(&uts_sem);
return err;
}
asmlinkage long solaris_syscall(struct pt_regs *regs)
{
static int count;
regs->tpc = regs->tnpc;
regs->tnpc += 4;
if (test_thread_flag(TIF_32BIT)) {
regs->tpc &= 0xffffffff;
regs->tnpc &= 0xffffffff;
}
if (++count <= 5) {
printk ("For Solaris binary emulation you need solaris module loaded\n");
show_regs (regs);
}
send_sig(SIGSEGV, current, 1);
return -ENOSYS;
}
#ifndef CONFIG_SUNOS_EMUL
asmlinkage long sunos_syscall(struct pt_regs *regs)
{
static int count;
regs->tpc = regs->tnpc;
regs->tnpc += 4;
if (test_thread_flag(TIF_32BIT)) {
regs->tpc &= 0xffffffff;
regs->tnpc &= 0xffffffff;
}
if (++count <= 20)
printk ("SunOS binary emulation not compiled in\n");
force_sig(SIGSEGV, current);
return -ENOSYS;
}
#endif
asmlinkage long sys_utrap_install(utrap_entry_t type,
utrap_handler_t new_p,
utrap_handler_t new_d,
utrap_handler_t __user *old_p,
utrap_handler_t __user *old_d)
{
if (type < UT_INSTRUCTION_EXCEPTION || type > UT_TRAP_INSTRUCTION_31)
return -EINVAL;
if (new_p == (utrap_handler_t)(long)UTH_NOCHANGE) {
if (old_p) {
if (!current_thread_info()->utraps) {
if (put_user(NULL, old_p))
return -EFAULT;
} else {
if (put_user((utrap_handler_t)(current_thread_info()->utraps[type]), old_p))
return -EFAULT;
}
}
if (old_d) {
if (put_user(NULL, old_d))
return -EFAULT;
}
return 0;
}
if (!current_thread_info()->utraps) {
current_thread_info()->utraps =
kmalloc((UT_TRAP_INSTRUCTION_31+1)*sizeof(long), GFP_KERNEL);
if (!current_thread_info()->utraps)
return -ENOMEM;
current_thread_info()->utraps[0] = 1;
memset(current_thread_info()->utraps+1, 0,
UT_TRAP_INSTRUCTION_31*sizeof(long));
} else {
if ((utrap_handler_t)current_thread_info()->utraps[type] != new_p &&
current_thread_info()->utraps[0] > 1) {
long *p = current_thread_info()->utraps;
current_thread_info()->utraps =
kmalloc((UT_TRAP_INSTRUCTION_31+1)*sizeof(long),
GFP_KERNEL);
if (!current_thread_info()->utraps) {
current_thread_info()->utraps = p;
return -ENOMEM;
}
p[0]--;
current_thread_info()->utraps[0] = 1;
memcpy(current_thread_info()->utraps+1, p+1,
UT_TRAP_INSTRUCTION_31*sizeof(long));
}
}
if (old_p) {
if (put_user((utrap_handler_t)(current_thread_info()->utraps[type]), old_p))
return -EFAULT;
}
if (old_d) {
if (put_user(NULL, old_d))
return -EFAULT;
}
current_thread_info()->utraps[type] = (long)new_p;
return 0;
}
long sparc_memory_ordering(unsigned long model, struct pt_regs *regs)
{
if (model >= 3)
return -EINVAL;
regs->tstate = (regs->tstate & ~TSTATE_MM) | (model << 14);
return 0;
}
asmlinkage long sys_rt_sigaction(int sig,
const struct sigaction __user *act,
struct sigaction __user *oact,
void __user *restorer,
size_t sigsetsize)
{
struct k_sigaction new_ka, old_ka;
int ret;
/* XXX: Don't preclude handling different sized sigset_t's. */
if (sigsetsize != sizeof(sigset_t))
return -EINVAL;
if (act) {
new_ka.ka_restorer = restorer;
if (copy_from_user(&new_ka.sa, act, sizeof(*act)))
return -EFAULT;
}
ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
if (!ret && oact) {
if (copy_to_user(oact, &old_ka.sa, sizeof(*oact)))
return -EFAULT;
}
return ret;
}
/* Invoked by rtrap code to update performance counters in
* user space.
*/
asmlinkage void update_perfctrs(void)
{
unsigned long pic, tmp;
read_pic(pic);
tmp = (current_thread_info()->kernel_cntd0 += (unsigned int)pic);
__put_user(tmp, current_thread_info()->user_cntd0);
tmp = (current_thread_info()->kernel_cntd1 += (pic >> 32));
__put_user(tmp, current_thread_info()->user_cntd1);
reset_pic();
}
asmlinkage long sys_perfctr(int opcode, unsigned long arg0, unsigned long arg1, unsigned long arg2)
{
int err = 0;
switch(opcode) {
case PERFCTR_ON:
current_thread_info()->pcr_reg = arg2;
current_thread_info()->user_cntd0 = (u64 __user *) arg0;
current_thread_info()->user_cntd1 = (u64 __user *) arg1;
current_thread_info()->kernel_cntd0 =
current_thread_info()->kernel_cntd1 = 0;
write_pcr(arg2);
reset_pic();
set_thread_flag(TIF_PERFCTR);
break;
case PERFCTR_OFF:
err = -EINVAL;
if (test_thread_flag(TIF_PERFCTR)) {
current_thread_info()->user_cntd0 =
current_thread_info()->user_cntd1 = NULL;
current_thread_info()->pcr_reg = 0;
write_pcr(0);
clear_thread_flag(TIF_PERFCTR);
err = 0;
}
break;
case PERFCTR_READ: {
unsigned long pic, tmp;
if (!test_thread_flag(TIF_PERFCTR)) {
err = -EINVAL;
break;
}
read_pic(pic);
tmp = (current_thread_info()->kernel_cntd0 += (unsigned int)pic);
err |= __put_user(tmp, current_thread_info()->user_cntd0);
tmp = (current_thread_info()->kernel_cntd1 += (pic >> 32));
err |= __put_user(tmp, current_thread_info()->user_cntd1);
reset_pic();
break;
}
case PERFCTR_CLRPIC:
if (!test_thread_flag(TIF_PERFCTR)) {
err = -EINVAL;
break;
}
current_thread_info()->kernel_cntd0 =
current_thread_info()->kernel_cntd1 = 0;
reset_pic();
break;
case PERFCTR_SETPCR: {
u64 __user *user_pcr = (u64 __user *)arg0;
if (!test_thread_flag(TIF_PERFCTR)) {
err = -EINVAL;
break;
}
err |= __get_user(current_thread_info()->pcr_reg, user_pcr);
write_pcr(current_thread_info()->pcr_reg);
current_thread_info()->kernel_cntd0 =
current_thread_info()->kernel_cntd1 = 0;
reset_pic();
break;
}
case PERFCTR_GETPCR: {
u64 __user *user_pcr = (u64 __user *)arg0;
if (!test_thread_flag(TIF_PERFCTR)) {
err = -EINVAL;
break;
}
err |= __put_user(current_thread_info()->pcr_reg, user_pcr);
break;
}
default:
err = -EINVAL;
break;
};
return err;
}
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