| Message ID | 20220525202600.2910982-5-roman.gushchin@linux.dev (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm: introduce shrinker debugfs interface | expand |
On Wed, May 25, 2022 at 01:25:58PM -0700, Roman Gushchin wrote: > Add a document describing the shrinker debugfs interface. > > Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Thanks.
On Wed, May 25, 2022 at 01:25:58PM -0700, Roman Gushchin wrote: > Add a document describing the shrinker debugfs interface. > > Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev> > --- > Documentation/admin-guide/mm/index.rst | 1 + > .../admin-guide/mm/shrinker_debugfs.rst | 100 ++++++++++++++++++ > 2 files changed, 101 insertions(+) > create mode 100644 Documentation/admin-guide/mm/shrinker_debugfs.rst > > diff --git a/Documentation/admin-guide/mm/index.rst b/Documentation/admin-guide/mm/index.rst > index c21b5823f126..1bd11118dfb1 100644 > --- a/Documentation/admin-guide/mm/index.rst > +++ b/Documentation/admin-guide/mm/index.rst > @@ -36,6 +36,7 @@ the Linux memory management. > numa_memory_policy > numaperf > pagemap > + shrinker_debugfs > soft-dirty > swap_numa > transhuge > diff --git a/Documentation/admin-guide/mm/shrinker_debugfs.rst b/Documentation/admin-guide/mm/shrinker_debugfs.rst > new file mode 100644 > index 000000000000..2033d696aa59 > --- /dev/null > +++ b/Documentation/admin-guide/mm/shrinker_debugfs.rst > @@ -0,0 +1,100 @@ > +.. _shrinker_debugfs: > + > +========================== > +Shrinker Debugfs Interface > +========================== > + > +Shrinker debugfs interface provides a visibility into the kernel memory > +shrinkers subsystem and allows to get information about individual shrinkers. > + > +For each shrinker registered in the system a directory in **<debugfs>/shrinker/** > +is created. The directory's name is composed from the shrinker's name and an > +unique id: e.g. *kfree_rcu-0* or *sb-xfs:vda1-36*. > + > +Each shrinker directory contains the **count** file, which allows to trigger > +the *count_objects()* callback for each memcg and numa node (if applicable). > + > +Usage: > +------ > + > +1. *List registered shrinkers* > + > + :: > + > + $ cd /sys/kernel/debug/shrinker/ > + $ ls > + dqcache-16 sb-hugetlbfs-17 sb-rootfs-2 sb-tmpfs-49 > + kfree_rcu-0 sb-hugetlbfs-33 sb-securityfs-6 sb-tracefs-13 > + sb-aio-20 sb-iomem-12 sb-selinuxfs-22 sb-xfs:vda1-36 > + sb-anon_inodefs-15 sb-mqueue-21 sb-sockfs-8 sb-zsmalloc-19 > + sb-bdev-3 sb-nsfs-4 sb-sysfs-26 shadow-18 > + sb-bpf-32 sb-pipefs-14 sb-tmpfs-1 thp_deferred_split-10 > + sb-btrfs:vda2-24 sb-proc-25 sb-tmpfs-27 thp_zero-9 > + sb-cgroup2-30 sb-proc-39 sb-tmpfs-29 xfs_buf-vda1-37 > + sb-configfs-23 sb-proc-41 sb-tmpfs-35 xfs_inodegc-vda1-38 > + sb-dax-11 sb-proc-45 sb-tmpfs-40 zspool-zram0-34 > + sb-debugfs-7 sb-proc-46 sb-tmpfs-42 > + sb-devpts-28 sb-proc-47 sb-tmpfs-43 > + sb-devtmpfs-5 sb-pstore-31 sb-tmpfs-44 > + > +2. *Get information about a specific shrinker* > + > + :: > + > + $ cd sb-btrfs\:vda2-24/ > + $ ls > + count > + > +3. *Count objects* > + > + Each line in the output has the following format:: > + > + <cgroup inode id> <nr of objects on node 0> <nr of objects on node 1> ... > + <cgroup inode id> <nr of objects on node 0> <nr of objects on node 1> ... > + ... > + > + If there are no objects on all numa nodes, a line is omitted. If there > + are no objects at all, the output might be empty. Should we add the following lines into here? " If the shrinker is not memcg-aware or CONFIG_MEMCG is off, 0 is printed as cgroup inode id. If the shrinker is not numa-aware, 0's are printed for all nodes except the first one. " Thanks.
On Thu, May 26, 2022 at 10:25:47AM +0800, Muchun Song wrote: > On Wed, May 25, 2022 at 01:25:58PM -0700, Roman Gushchin wrote: > > Add a document describing the shrinker debugfs interface. > > > > Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev> > > --- > > Documentation/admin-guide/mm/index.rst | 1 + > > .../admin-guide/mm/shrinker_debugfs.rst | 100 ++++++++++++++++++ > > 2 files changed, 101 insertions(+) > > create mode 100644 Documentation/admin-guide/mm/shrinker_debugfs.rst > > > > diff --git a/Documentation/admin-guide/mm/index.rst b/Documentation/admin-guide/mm/index.rst > > index c21b5823f126..1bd11118dfb1 100644 > > --- a/Documentation/admin-guide/mm/index.rst > > +++ b/Documentation/admin-guide/mm/index.rst > > @@ -36,6 +36,7 @@ the Linux memory management. > > numa_memory_policy > > numaperf > > pagemap > > + shrinker_debugfs > > soft-dirty > > swap_numa > > transhuge > > diff --git a/Documentation/admin-guide/mm/shrinker_debugfs.rst b/Documentation/admin-guide/mm/shrinker_debugfs.rst > > new file mode 100644 > > index 000000000000..2033d696aa59 > > --- /dev/null > > +++ b/Documentation/admin-guide/mm/shrinker_debugfs.rst > > @@ -0,0 +1,100 @@ > > +.. _shrinker_debugfs: > > + > > +========================== > > +Shrinker Debugfs Interface > > +========================== > > + > > +Shrinker debugfs interface provides a visibility into the kernel memory > > +shrinkers subsystem and allows to get information about individual shrinkers. > > + > > +For each shrinker registered in the system a directory in **<debugfs>/shrinker/** > > +is created. The directory's name is composed from the shrinker's name and an > > +unique id: e.g. *kfree_rcu-0* or *sb-xfs:vda1-36*. > > + > > +Each shrinker directory contains the **count** file, which allows to trigger > > +the *count_objects()* callback for each memcg and numa node (if applicable). > > + > > +Usage: > > +------ > > + > > +1. *List registered shrinkers* > > + > > + :: > > + > > + $ cd /sys/kernel/debug/shrinker/ > > + $ ls > > + dqcache-16 sb-hugetlbfs-17 sb-rootfs-2 sb-tmpfs-49 > > + kfree_rcu-0 sb-hugetlbfs-33 sb-securityfs-6 sb-tracefs-13 > > + sb-aio-20 sb-iomem-12 sb-selinuxfs-22 sb-xfs:vda1-36 > > + sb-anon_inodefs-15 sb-mqueue-21 sb-sockfs-8 sb-zsmalloc-19 > > + sb-bdev-3 sb-nsfs-4 sb-sysfs-26 shadow-18 > > + sb-bpf-32 sb-pipefs-14 sb-tmpfs-1 thp_deferred_split-10 > > + sb-btrfs:vda2-24 sb-proc-25 sb-tmpfs-27 thp_zero-9 > > + sb-cgroup2-30 sb-proc-39 sb-tmpfs-29 xfs_buf-vda1-37 > > + sb-configfs-23 sb-proc-41 sb-tmpfs-35 xfs_inodegc-vda1-38 > > + sb-dax-11 sb-proc-45 sb-tmpfs-40 zspool-zram0-34 > > + sb-debugfs-7 sb-proc-46 sb-tmpfs-42 > > + sb-devpts-28 sb-proc-47 sb-tmpfs-43 > > + sb-devtmpfs-5 sb-pstore-31 sb-tmpfs-44 > > + > > +2. *Get information about a specific shrinker* > > + > > + :: > > + > > + $ cd sb-btrfs\:vda2-24/ > > + $ ls > > + count > > + > > +3. *Count objects* > > + > > + Each line in the output has the following format:: > > + > > + <cgroup inode id> <nr of objects on node 0> <nr of objects on node 1> ... > > + <cgroup inode id> <nr of objects on node 0> <nr of objects on node 1> ... > > + ... > > + > > + If there are no objects on all numa nodes, a line is omitted. If there > > + are no objects at all, the output might be empty. > > Should we add the following lines into here? > > " > If the shrinker is not memcg-aware or CONFIG_MEMCG is off, 0 is > printed as cgroup inode id. If the shrinker is not numa-aware, 0's are > printed for all nodes except the first one. > " Yes, it sounds like a great addition. I hope Andrew can merge this in if there will be no v5. Or I'll add it by myself otherwise. Thanks! And thank you for reviewing the patches!
diff --git a/Documentation/admin-guide/mm/index.rst b/Documentation/admin-guide/mm/index.rst index c21b5823f126..1bd11118dfb1 100644 --- a/Documentation/admin-guide/mm/index.rst +++ b/Documentation/admin-guide/mm/index.rst @@ -36,6 +36,7 @@ the Linux memory management. numa_memory_policy numaperf pagemap + shrinker_debugfs soft-dirty swap_numa transhuge diff --git a/Documentation/admin-guide/mm/shrinker_debugfs.rst b/Documentation/admin-guide/mm/shrinker_debugfs.rst new file mode 100644 index 000000000000..2033d696aa59 --- /dev/null +++ b/Documentation/admin-guide/mm/shrinker_debugfs.rst @@ -0,0 +1,100 @@ +.. _shrinker_debugfs: + +========================== +Shrinker Debugfs Interface +========================== + +Shrinker debugfs interface provides a visibility into the kernel memory +shrinkers subsystem and allows to get information about individual shrinkers. + +For each shrinker registered in the system a directory in **<debugfs>/shrinker/** +is created. The directory's name is composed from the shrinker's name and an +unique id: e.g. *kfree_rcu-0* or *sb-xfs:vda1-36*. + +Each shrinker directory contains the **count** file, which allows to trigger +the *count_objects()* callback for each memcg and numa node (if applicable). + +Usage: +------ + +1. *List registered shrinkers* + + :: + + $ cd /sys/kernel/debug/shrinker/ + $ ls + dqcache-16 sb-hugetlbfs-17 sb-rootfs-2 sb-tmpfs-49 + kfree_rcu-0 sb-hugetlbfs-33 sb-securityfs-6 sb-tracefs-13 + sb-aio-20 sb-iomem-12 sb-selinuxfs-22 sb-xfs:vda1-36 + sb-anon_inodefs-15 sb-mqueue-21 sb-sockfs-8 sb-zsmalloc-19 + sb-bdev-3 sb-nsfs-4 sb-sysfs-26 shadow-18 + sb-bpf-32 sb-pipefs-14 sb-tmpfs-1 thp_deferred_split-10 + sb-btrfs:vda2-24 sb-proc-25 sb-tmpfs-27 thp_zero-9 + sb-cgroup2-30 sb-proc-39 sb-tmpfs-29 xfs_buf-vda1-37 + sb-configfs-23 sb-proc-41 sb-tmpfs-35 xfs_inodegc-vda1-38 + sb-dax-11 sb-proc-45 sb-tmpfs-40 zspool-zram0-34 + sb-debugfs-7 sb-proc-46 sb-tmpfs-42 + sb-devpts-28 sb-proc-47 sb-tmpfs-43 + sb-devtmpfs-5 sb-pstore-31 sb-tmpfs-44 + +2. *Get information about a specific shrinker* + + :: + + $ cd sb-btrfs\:vda2-24/ + $ ls + count + +3. *Count objects* + + Each line in the output has the following format:: + + <cgroup inode id> <nr of objects on node 0> <nr of objects on node 1> ... + <cgroup inode id> <nr of objects on node 0> <nr of objects on node 1> ... + ... + + If there are no objects on all numa nodes, a line is omitted. If there + are no objects at all, the output might be empty. + :: + + $ cat count + 1 224 2 + 21 98 0 + 55 818 10 + 2367 2 0 + 2401 30 0 + 225 13 0 + 599 35 0 + 939 124 0 + 1041 3 0 + 1075 1 0 + 1109 1 0 + 1279 60 0 + 1313 7 0 + 1347 39 0 + 1381 3 0 + 1449 14 0 + 1483 63 0 + 1517 53 0 + 1551 6 0 + 1585 1 0 + 1619 6 0 + 1653 40 0 + 1687 11 0 + 1721 8 0 + 1755 4 0 + 1789 52 0 + 1823 888 0 + 1857 1 0 + 1925 2 0 + 1959 32 0 + 2027 22 0 + 2061 9 0 + 2469 799 0 + 2537 861 0 + 2639 1 0 + 2707 70 0 + 2775 4 0 + 2877 84 0 + 293 1 0 + 735 8 0
Add a document describing the shrinker debugfs interface. Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev> --- Documentation/admin-guide/mm/index.rst | 1 + .../admin-guide/mm/shrinker_debugfs.rst | 100 ++++++++++++++++++ 2 files changed, 101 insertions(+) create mode 100644 Documentation/admin-guide/mm/shrinker_debugfs.rst