diff options
| author | Andrew Morton <akpm@osdl.org> | 2006-01-08 01:00:39 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-01-08 20:12:40 -0800 |
| commit | 9d0243bca345d5ce25d3f4b74b7facb3a6df1232 (patch) | |
| tree | a3a0a763bf83a483282dc1c3caab587941a98fc2 /kernel | |
| parent | bec6b0c89b234090681a4516e20ac5debe3e7c59 (diff) | |
| download | lwn-9d0243bca345d5ce25d3f4b74b7facb3a6df1232.tar.gz lwn-9d0243bca345d5ce25d3f4b74b7facb3a6df1232.zip | |
[PATCH] drop-pagecache
Add /proc/sys/vm/drop_caches. When written to, this will cause the kernel to
discard as much pagecache and/or reclaimable slab objects as it can. THis
operation requires root permissions.
It won't drop dirty data, so the user should run `sync' first.
Caveats:
a) Holds inode_lock for exorbitant amounts of time.
b) Needs to be taught about NUMA nodes: propagate these all the way through
so the discarding can be controlled on a per-node basis.
This is a debugging feature: useful for getting consistent results between
filesystem benchmarks. We could possibly put it under a config option, but
it's less than 300 bytes.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sysctl.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/kernel/sysctl.c b/kernel/sysctl.c index a85047bb5739..8dcf6fd5b0f9 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -68,6 +68,7 @@ extern int min_free_kbytes; extern int printk_ratelimit_jiffies; extern int printk_ratelimit_burst; extern int pid_max_min, pid_max_max; +extern int sysctl_drop_caches; #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86) int unknown_nmi_panic; @@ -775,6 +776,15 @@ static ctl_table vm_table[] = { .strategy = &sysctl_intvec, }, { + .ctl_name = VM_DROP_PAGECACHE, + .procname = "drop_caches", + .data = &sysctl_drop_caches, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = drop_caches_sysctl_handler, + .strategy = &sysctl_intvec, + }, + { .ctl_name = VM_MIN_FREE_KBYTES, .procname = "min_free_kbytes", .data = &min_free_kbytes, |