On Fri, May 27, 2022 at 07:30:34PM +1000, Dave Chinner wrote: > 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 Ok, good point, will do in the next version. > > 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? I agree, but I've no good idea what to use as an id. We can't put the mount point, user, group etc together in the file name - it will be too lengthy (and mount namespaces are making it even more complicated). Maybe we can add a symlink to the mount point from within the directory? Do you have any ideas here? Thanks!
