[PATCH -mmotm 1/4] memcg: dirty memory documentation
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From: Andrea Righi on 4 Mar 2010 05:50 Document cgroup dirty memory interfaces and statistics. Signed-off-by: Andrea Righi <arighi(a)develer.com> --- Documentation/cgroups/memory.txt | 36 ++++++++++++++++++++++++++++++++++++ 1 files changed, 36 insertions(+), 0 deletions(-) diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt index 49f86f3..38ca499 100644 --- a/Documentation/cgroups/memory.txt +++ b/Documentation/cgroups/memory.txt @@ -310,6 +310,11 @@ cache - # of bytes of page cache memory. rss - # of bytes of anonymous and swap cache memory. pgpgin - # of pages paged in (equivalent to # of charging events). pgpgout - # of pages paged out (equivalent to # of uncharging events). +filedirty - # of pages that are waiting to get written back to the disk. +writeback - # of pages that are actively being written back to the disk. +writeback_tmp - # of pages used by FUSE for temporary writeback buffers. +nfs - # of NFS pages sent to the server, but not yet committed to + the actual storage. active_anon - # of bytes of anonymous and swap cache memory on active lru list. inactive_anon - # of bytes of anonymous memory and swap cache memory on @@ -345,6 +350,37 @@ Note: - a cgroup which uses hierarchy and it has child cgroup. - a cgroup which uses hierarchy and not the root of hierarchy. +5.4 dirty memory + + Control the maximum amount of dirty pages a cgroup can have at any given time. + + Limiting dirty memory is like fixing the max amount of dirty (hard to + reclaim) page cache used by any cgroup. So, in case of multiple cgroup writers, + they will not be able to consume more than their designated share of dirty + pages and will be forced to perform write-out if they cross that limit. + + The interface is equivalent to the procfs interface: /proc/sys/vm/dirty_*. + It is possible to configure a limit to trigger both a direct writeback or a + background writeback performed by per-bdi flusher threads. + + Per-cgroup dirty limits can be set using the following files in the cgroupfs: + + - memory.dirty_ratio: contains, as a percentage of cgroup memory, the + amount of dirty memory at which a process which is generating disk writes + inside the cgroup will start itself writing out dirty data. + + - memory.dirty_bytes: the amount of dirty memory of the cgroup (expressed in + bytes) at which a process generating disk writes will start itself writing + out dirty data. + + - memory.dirty_background_ratio: contains, as a percentage of the cgroup + memory, the amount of dirty memory at which background writeback kernel + threads will start writing out dirty data. + + - memory.dirty_background_bytes: the amount of dirty memory of the cgroup (in + bytes) at which background writeback kernel threads will start writing out + dirty data. + 6. Hierarchy support -- 1.6.3.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |