linux/arch/arm/mm
Hugh Dickins 4c21e2f244 [PATCH] mm: split page table lock
Christoph Lameter demonstrated very poor scalability on the SGI 512-way, with
a many-threaded application which concurrently initializes different parts of
a large anonymous area.

This patch corrects that, by using a separate spinlock per page table page, to
guard the page table entries in that page, instead of using the mm's single
page_table_lock.  (But even then, page_table_lock is still used to guard page
table allocation, and anon_vma allocation.)

In this implementation, the spinlock is tucked inside the struct page of the
page table page: with a BUILD_BUG_ON in case it overflows - which it would in
the case of 32-bit PA-RISC with spinlock debugging enabled.

Splitting the lock is not quite for free: another cacheline access.  Ideally,
I suppose we would use split ptlock only for multi-threaded processes on
multi-cpu machines; but deciding that dynamically would have its own costs.
So for now enable it by config, at some number of cpus - since the Kconfig
language doesn't support inequalities, let preprocessor compare that with
NR_CPUS.  But I don't think it's worth being user-configurable: for good
testing of both split and unsplit configs, split now at 4 cpus, and perhaps
change that to 8 later.

There is a benefit even for singly threaded processes: kswapd can be attacking
one part of the mm while another part is busy faulting.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29 21:40:42 -07:00
..
abort-ev4.S Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
abort-ev4t.S Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
abort-ev5t.S Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
abort-ev5tj.S Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
abort-ev6.S [ARM] 2943/1: Clear the exclusive monitor in v6_early_abort 2005-10-02 22:34:35 +01:00
abort-lv4t.S Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
abort-macro.S Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
alignment.c [ARM] 2969/1: miscellaneous whitespace cleanup 2005-10-12 19:58:10 +01:00
blockops.c [PATCH] ARM: 2784/1: Fix the block cache flush operation range 2005-07-03 17:53:25 +01:00
cache-v3.S Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
cache-v4.S Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
cache-v4wb.S Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
cache-v4wt.S Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
cache-v6.S [ARM] 2940/1: Fix BTB entry flush in arch/arm/mm/cache-v6.S 2005-09-30 16:09:17 +01:00
consistent.c [PATCH] mm: init_mm without ptlock 2005-10-29 21:40:40 -07:00
copypage-v3.S kbuild: arm - use generic asm-offsets.h support 2005-09-09 21:08:59 +02:00
copypage-v4mc.c [PATCH] ARM: Fix build error 2005-05-16 23:36:22 +01:00
copypage-v4wb.S kbuild: arm - use generic asm-offsets.h support 2005-09-09 21:08:59 +02:00
copypage-v4wt.S kbuild: arm - use generic asm-offsets.h support 2005-09-09 21:08:59 +02:00
copypage-v6.c [PATCH] ARM: Add common CACHE_COLOUR macro 2005-06-20 11:31:09 +01:00
copypage-xscale.c [PATCH] ARM: Fix Xscale copy_page implementation 2005-06-08 15:28:24 +01:00
discontig.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
extable.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
fault-armv.c [PATCH] mm: arm ready for split ptlock 2005-10-29 21:40:42 -07:00
fault.c [ARM] Prevent deadlock in page fault handler 2005-09-20 17:52:13 +01:00
fault.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
flush.c [ARM] 2939/1: Fix compilation error in arch/arm/mm/flush.c 2005-09-30 16:07:04 +01:00
init.c [ARM] 3059/1: fix XIP support 2005-10-29 16:28:29 +01:00
ioremap.c [PATCH] mm: init_mm without ptlock 2005-10-29 21:40:40 -07:00
Kconfig [ARM] 2954/1: Allow D and I cache and branch prediction disabling for ARMv6 2005-10-05 23:06:36 +01:00
Makefile [PATCH] ARM: Fix Xscale copy_page implementation 2005-06-08 15:28:24 +01:00
mm-armv.c [PATCH] mm: split page table lock 2005-10-29 21:40:42 -07:00
mmap.c [PATCH] Avoiding mmap fragmentation 2005-06-21 18:46:16 -07:00
mmu.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
proc-arm6_7.S [ARM] 2926/1: .proc.info - postfix section with .init for make buildcheck 2005-09-20 16:35:03 +01:00
proc-arm720.S [ARM] 2926/1: .proc.info - postfix section with .init for make buildcheck 2005-09-20 16:35:03 +01:00
proc-arm920.S [ARM] 2926/1: .proc.info - postfix section with .init for make buildcheck 2005-09-20 16:35:03 +01:00
proc-arm922.S [ARM] 2926/1: .proc.info - postfix section with .init for make buildcheck 2005-09-20 16:35:03 +01:00
proc-arm925.S [ARM] 2926/1: .proc.info - postfix section with .init for make buildcheck 2005-09-20 16:35:03 +01:00
proc-arm926.S [ARM] 2926/1: .proc.info - postfix section with .init for make buildcheck 2005-09-20 16:35:03 +01:00
proc-arm1020.S [ARM] 2926/1: .proc.info - postfix section with .init for make buildcheck 2005-09-20 16:35:03 +01:00
proc-arm1020e.S [ARM] 2926/1: .proc.info - postfix section with .init for make buildcheck 2005-09-20 16:35:03 +01:00
proc-arm1022.S [ARM] 2926/1: .proc.info - postfix section with .init for make buildcheck 2005-09-20 16:35:03 +01:00
proc-arm1026.S [ARM] 2926/1: .proc.info - postfix section with .init for make buildcheck 2005-09-20 16:35:03 +01:00
proc-macros.S kbuild: arm - use generic asm-offsets.h support 2005-09-09 21:08:59 +02:00
proc-sa110.S [ARM] 2926/1: .proc.info - postfix section with .init for make buildcheck 2005-09-20 16:35:03 +01:00
proc-sa1100.S [ARM] 2926/1: .proc.info - postfix section with .init for make buildcheck 2005-09-20 16:35:03 +01:00
proc-syms.c Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
proc-v6.S [ARM] 3024/1: Add cpu_v6_proc_fin 2005-10-19 23:00:56 +01:00
proc-xscale.S [ARM] 2926/1: .proc.info - postfix section with .init for make buildcheck 2005-09-20 16:35:03 +01:00
tlb-v3.S kbuild: arm - use generic asm-offsets.h support 2005-09-09 21:08:59 +02:00
tlb-v4.S kbuild: arm - use generic asm-offsets.h support 2005-09-09 21:08:59 +02:00
tlb-v4wb.S kbuild: arm - use generic asm-offsets.h support 2005-09-09 21:08:59 +02:00
tlb-v4wbi.S kbuild: arm - use generic asm-offsets.h support 2005-09-09 21:08:59 +02:00
tlb-v6.S kbuild: arm - use generic asm-offsets.h support 2005-09-09 21:08:59 +02:00