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| author | Bron Gondwana <brong@fastmail.fm> | 2008-02-04 22:29:20 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2008-02-05 09:44:18 -0800 |
| commit | 195cf453d2c3d789cbe80e3735755f860c2fb222 (patch) | |
| tree | fad48a8167744b6c091c8ca499bc78b859af8957 /kernel/sysctl.c | |
| parent | 3dfa5721f12c3d5a441448086bee156887daa961 (diff) | |
| download | lwn-195cf453d2c3d789cbe80e3735755f860c2fb222.tar.gz lwn-195cf453d2c3d789cbe80e3735755f860c2fb222.zip | |
mm/page-writeback: highmem_is_dirtyable option
Add vm.highmem_is_dirtyable toggle
A 32 bit machine with HIGHMEM64 enabled running DCC has an MMAPed file of
approximately 2Gb size which contains a hash format that is written
randomly by the dbclean process. On 2.6.16 this process took a few
minutes. With lowmem only accounting of dirty ratios, this takes about 12
hours of 100% disk IO, all random writes.
Include a toggle in /proc/sys/vm/highmem_is_dirtyable which can be set to 1 to
add the highmem back to the total available memory count.
[akpm@linux-foundation.org: Fix the CONFIG_DETECT_SOFTLOCKUP=y build]
Signed-off-by: Bron Gondwana <brong@fastmail.fm>
Cc: Ethan Solomita <solo@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: WU Fengguang <wfg@mail.ustc.edu.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/sysctl.c')
| -rw-r--r-- | kernel/sysctl.c | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 7cb1ac3e6fff..d0b47b859067 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -84,8 +84,11 @@ extern int sysctl_stat_interval; extern int latencytop_enabled; /* Constants used for minimum and maximum */ -#ifdef CONFIG_DETECT_SOFTLOCKUP +#if defined(CONFIG_DETECT_SOFTLOCKUP) || defined(CONFIG_HIGHMEM) static int one = 1; +#endif + +#ifdef CONFIG_DETECT_SOFTLOCKUP static int sixty = 60; #endif @@ -1150,6 +1153,19 @@ static struct ctl_table vm_table[] = { .extra1 = &zero, }, #endif +#ifdef CONFIG_HIGHMEM + { + .ctl_name = CTL_UNNUMBERED, + .procname = "highmem_is_dirtyable", + .data = &vm_highmem_is_dirtyable, + .maxlen = sizeof(vm_highmem_is_dirtyable), + .mode = 0644, + .proc_handler = &proc_dointvec_minmax, + .strategy = &sysctl_intvec, + .extra1 = &zero, + .extra2 = &one, + }, +#endif /* * NOTE: do not add new entries to this table unless you have read * Documentation/sysctl/ctl_unnumbered.txt |