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authorAndrew Morton <akpm@osdl.org>2006-01-08 01:00:39 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-01-08 20:12:40 -0800
commit9d0243bca345d5ce25d3f4b74b7facb3a6df1232 (patch)
treea3a0a763bf83a483282dc1c3caab587941a98fc2 /include
parentbec6b0c89b234090681a4516e20ac5debe3e7c59 (diff)
[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 'include')
-rw-r--r--include/linux/mm.h7
-rw-r--r--include/linux/sysctl.h1
2 files changed, 8 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h
index bc01fff3aa0..83c651f2518 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1036,5 +1036,12 @@ int in_gate_area_no_task(unsigned long addr);
/* /proc/<pid>/oom_adj set to -17 protects from the oom-killer */
#define OOM_DISABLE -17
+int drop_caches_sysctl_handler(struct ctl_table *, int, struct file *,
+ void __user *, size_t *, loff_t *);
+int shrink_slab(unsigned long scanned, gfp_t gfp_mask,
+ unsigned long lru_pages);
+void drop_pagecache(void);
+void drop_slab(void);
+
#endif /* __KERNEL__ */
#endif /* _LINUX_MM_H */
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index a9b80fc7f0f..4cd267fe87e 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -180,6 +180,7 @@ enum
VM_VFS_CACHE_PRESSURE=26, /* dcache/icache reclaim pressure */
VM_LEGACY_VA_LAYOUT=27, /* legacy/compatibility virtual address space layout */
VM_SWAP_TOKEN_TIMEOUT=28, /* default time for token time out */
+ VM_DROP_PAGECACHE=29, /* int: nuke lots of pagecache */
};