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authorDennis Zhou (Facebook) <dennisszhou@gmail.com>2018-08-21 21:53:58 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-08-22 10:52:45 -0700
commit7e8a6304d5419cbf056a59de92939e5eef039c57 (patch)
tree6fa617d1ee50064ee3b93f1f95740d54ed883f18 /Documentation/filesystems/proc.txt
parent3d8b38eb81cac81395f6a823f6bf401b327268e6 (diff)
downloadlwn-7e8a6304d5419cbf056a59de92939e5eef039c57.tar.gz
lwn-7e8a6304d5419cbf056a59de92939e5eef039c57.zip
/proc/meminfo: add percpu populated pages count
Currently, percpu memory only exposes allocation and utilization information via debugfs. This more or less is only really useful for understanding the fragmentation and allocation information at a per-chunk level with a few global counters. This is also gated behind a config. BPF and cgroup, for example, have seen an increase in use causing increased use of percpu memory. Let's make it easier for someone to identify how much memory is being used. This patch adds the "Percpu" stat to meminfo to more easily look up how much percpu memory is in use. This number includes the cost for all allocated backing pages and not just insight at the per a unit, per chunk level. Metadata is excluded. I think excluding metadata is fair because the backing memory scales with the numbere of cpus and can quickly outweigh the metadata. It also makes this calculation light. Link: http://lkml.kernel.org/r/20180807184723.74919-1-dennisszhou@gmail.com Signed-off-by: Dennis Zhou <dennisszhou@gmail.com> Acked-by: Tejun Heo <tj@kernel.org> Acked-by: Roman Gushchin <guro@fb.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Christoph Lameter <cl@linux.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation/filesystems/proc.txt')
-rw-r--r--Documentation/filesystems/proc.txt3
1 files changed, 3 insertions, 0 deletions
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index 1605acbb23b6..22b4b00dee31 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -870,6 +870,7 @@ Committed_AS: 100056 kB
VmallocTotal: 112216 kB
VmallocUsed: 428 kB
VmallocChunk: 111088 kB
+Percpu: 62080 kB
HardwareCorrupted: 0 kB
AnonHugePages: 49152 kB
ShmemHugePages: 0 kB
@@ -962,6 +963,8 @@ Committed_AS: The amount of memory presently allocated on the system.
VmallocTotal: total size of vmalloc memory area
VmallocUsed: amount of vmalloc area which is used
VmallocChunk: largest contiguous block of vmalloc area which is free
+ Percpu: Memory allocated to the percpu allocator used to back percpu
+ allocations. This stat excludes the cost of metadata.
..............................................................................