lkml.org 
[lkml]   [2022]   [May]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v4 3/6] mm: shrinkers: provide shrinkers with names
On Wed, May 25, 2022 at 01:25:57PM -0700, Roman Gushchin wrote:
> Currently shrinkers are anonymous objects. For debugging purposes they
> can be identified by count/scan function names, but it's not always
> useful: e.g. for superblock's shrinkers it's nice to have at least
> an idea of to which superblock the shrinker belongs.
>
> This commit adds names to shrinkers. register_shrinker() and
> prealloc_shrinker() functions are extended to take a format and
> arguments to master a name.
>
> In some cases it's not possible to determine a good name at the time
> when a shrinker is allocated. For such cases shrinker_debugfs_rename()
> is provided.
>
> After this change the shrinker debugfs directory looks like:
> $ 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-xfs:vda1-36
xfs_buf-vda1-37
xfs_inodegc-vda1-38

That's a parsing nightmare right there. Please use the same format
for everything. You have <subsystem>-<type>:<instance>-<id> for
superblock stuff, but <subsys>_<type>-<instance>-<id> for the XFS
stuff. Make it consistent so we aren't reduced to pulling out our
hair trying to parse this in any useful way:

sb-xfs:vda1-36
xfs-buf:vda1-37
xfs-inodegc:vda1-38

FWIW, how we are supposed to know what actually owns these:

sb-tmpfs-1
sb-tmpfs-27
sb-tmpfs-29
sb-tmpfs-35
sb-tmpfs-49

tmpfs-27 might own all the memory - how do we link that back to a
mount point, container, user, workload, etc?

Cheers,

Dave.
--
Dave Chinner
dchinner@redhat.com

\
 
 \ /
  Last update: 2022-05-27 11:31    [W:0.152 / U:0.316 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site