On Tue, Mar 16, 2010 at 04:41:21PM +0900, Daisuke Nishimura wrote: > On Mon, 15 Mar 2010 00:26:39 +0100, Andrea Righi <arighi@xxxxxxxxxxx> wrote: > > Document cgroup dirty memory interfaces and statistics. > > > > Signed-off-by: Andrea Righi <arighi@xxxxxxxxxxx> > > --- > > 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. > > + > > > It would be better to note that what those files of root cgroup mean. > We cannot write any value to them, IOW, we cannot control dirty limit about root cgroup. OK. > And they show the same value as the global one(strictly speaking, it's not true > because global values can change. We need a hook in mem_cgroup_dirty_read()?). OK, we can just return system-wide value if mem_cgroup_is_root() in mem_cgroup_dirty_read(). Will change this in the next version. Thanks, -Andrea -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>