linux/include
Hideo AOKI cb45b0e966 [PATCH] overcommit: add calculate_totalreserve_pages()
These patches are an enhancement of OVERCOMMIT_GUESS algorithm in
__vm_enough_memory().

- why the kernel needed patching

  When the kernel can't allocate anonymous pages in practice, currnet
  OVERCOMMIT_GUESS could return success. This implementation might be
  the cause of oom kill in memory pressure situation.

  If the Linux runs with page reservation features like
  /proc/sys/vm/lowmem_reserve_ratio and without swap region, I think
  the oom kill occurs easily.

- the overall design approach in the patch

  When the OVERCOMMET_GUESS algorithm calculates number of free pages,
  the reserved free pages are regarded as non-free pages.

  This change helps to avoid the pitfall that the number of free pages
  become less than the number which the kernel tries to keep free.

- testing results

  I tested the patches using my test kernel module.

  If the patches aren't applied to the kernel, __vm_enough_memory()
  returns success in the situation but autual page allocation is
  failed.

  On the other hand, if the patches are applied to the kernel, memory
  allocation failure is avoided since __vm_enough_memory() returns
  failure in the situation.

  I checked that on i386 SMP 16GB memory machine. I haven't tested on
  nommu environment currently.

This patch adds totalreserve_pages for __vm_enough_memory().

Calculate_totalreserve_pages() checks maximum lowmem_reserve pages and
pages_high in each zone. Finally, the function stores the sum of each
zone to totalreserve_pages.

The totalreserve_pages is calculated when the VM is initilized.
And the variable is updated when /proc/sys/vm/lowmem_reserve_raito
or /proc/sys/vm/min_free_kbytes are changed.

Signed-off-by: Hideo Aoki <haoki@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-11 06:18:32 -07:00
..
acpi [PATCH] s/;;/;/g 2006-03-24 07:33:24 -08:00
asm-alpha [PATCH] alpha: make poll flags the same as other architectures 2006-03-28 09:16:02 -08:00
asm-arm [ARM] 3472/1: Use the D variants of FLDMIA/FSTMIA on ARMv6 2006-04-10 21:32:42 +01:00
asm-arm26 [PATCH] unify pfn_to_page: arm26 pfn_to_page 2006-03-27 08:44:44 -08:00
asm-cris [PATCH] unify pfn_to_page: cris pfn_to_page 2006-03-27 08:44:45 -08:00
asm-frv [PATCH] lightweight robust futexes updates 2006-03-27 08:44:49 -08:00
asm-generic [PATCH] mutex: some cleanups 2006-03-31 12:19:01 -08:00
asm-h8300 [PATCH] unify pfn_to_page: h8300 pfn_to_page 2006-03-27 08:44:45 -08:00
asm-i386 [PATCH] x86_64: Fix drift with HPET timer enabled 2006-04-09 11:53:53 -07:00
asm-ia64 [IA64] Avoid "u64 foo : 32;" for gcc3 vs. gcc4 compatibility 2006-03-31 10:28:29 -08:00
asm-m32r [PATCH] unify PFN_* macros 2006-03-27 08:44:48 -08:00
asm-m68k [PATCH] m68k: fix undefined reference to generic_find_next_zero_le_bit 2006-03-26 08:57:13 -08:00
asm-m68knommu [PATCH] bitops: m68knommu: use generic bitops 2006-03-26 08:57:13 -08:00
asm-mips Merge master.kernel.org:/home/rmk/linux-2.6-serial 2006-03-28 13:52:37 -08:00
asm-parisc [PARISC] Add atomic_sub_and_test 2006-03-30 17:48:59 +00:00
asm-powerpc [PATCH] powerpc/pseries: EEH Cleanup 2006-04-01 22:37:11 +11:00
asm-ppc [PATCH] lock PTE before updating it in 440/BookE page fault handler 2006-03-29 13:44:15 +11:00
asm-s390 [PATCH] for_each_possible_cpu: s390 2006-03-31 12:18:52 -08:00
asm-sh [PATCH] Typo fixes 2006-03-28 09:16:08 -08:00
asm-sh64 [PATCH] unify PFN_* macros 2006-03-27 08:44:48 -08:00
asm-sparc [SPARC]: Wire up sys_sync_file_range() into syscall tables. 2006-03-31 23:49:34 -08:00
asm-sparc64 [PATCH] for_each_possible_cpu: sparc64 2006-04-11 06:18:31 -07:00
asm-um [PATCH] uml: check for differences in host support 2006-03-31 12:18:52 -08:00
asm-v850 [PATCH] unify pfn_to_page: v850 pfn_to_page 2006-03-27 08:44:47 -08:00
asm-x86_64 [PATCH] x86_64: Eliminate IA32_NR_syscalls define 2006-04-09 11:53:53 -07:00
asm-xtensa [PATCH] unify pfn_to_page: xtensa pfn_to_page 2006-03-27 08:44:47 -08:00
keys
linux [PATCH] overcommit: add calculate_totalreserve_pages() 2006-04-11 06:18:32 -07:00
math-emu
media V4L/DVB (3702): Make msp3400 routing defines more consistent 2006-04-02 04:56:11 -03:00
mtd
net [IPV6]: Deinline few large functions in inet6 code 2006-04-09 22:48:59 -07:00
pcmcia [PATCH] pcmcia: declare pccard_iodyn_ops (fix m8xx_pcmcia.c compilation error) 2006-03-31 21:49:51 +02:00
rdma IB/mad: RMPP support for additional classes 2006-03-30 07:19:51 -08:00
rxrpc
scsi [PATCH] move ->eh_strategy_handler to the transport class 2006-04-10 14:15:47 -04:00
sound Update dummy snd_power_wait() function for new calling convention 2006-04-02 14:37:36 -07:00
video [PATCH] Remove MODULE_PARM 2006-03-25 08:22:52 -08:00