Re: [PATCH v3 0/3] add support for drop_caches for individual filesystem

[Muchun Song <muchun.song@linux.dev>]

> On Feb 27, 2026, at 10:55, Ye Bin <yebin@huaweicloud.com> wrote:
> 
> From: Ye Bin <yebin10@huawei.com>
> 
> In order to better analyze the issue of file system uninstallation caused
> by kernel module opening files, it is necessary to perform dentry recycling
> on a single file system. But now, apart from global dentry recycling, it is
> not supported to do dentry recycling on a single file system separately.

Would shrinker-debugfs satisfy your needs (See Documentation/admin-guide/mm/shrinker_debugfs.rst)?

Thanks,
Muchun

> This feature has usage scenarios in problem localization scenarios.At the
> same time, it also provides users with a slightly fine-grained
> pagecache/entry recycling mechanism.
> This patchset supports the recycling of pagecache/entry for individual file
> systems.
> 
> Diff v3 vs v2
> 1. Introduce introduce drop_sb_dentry_inode() helper instead of
> reclaim_dcache_sb()/reclaim_icache_sb() helper for reclaim dentry/inode.
> 2. Fixing compilation issues in specific architectures and configurations.
> 
> Diff v2 vs v1:
> 1. Fix possible live lock for shrink_icache_sb().
> 2. Introduce reclaim_dcache_sb() for reclaim dentry.
> 3. Fix potential deadlocks as follows:
> https://lore.kernel.org/linux-fsdevel/00000000000098f75506153551a1@google.com/
> After some consideration, it was decided that this feature would primarily
> be used for debugging purposes. Instead of adding a new IOCTL command, the
> task_work mechanism was employed to address potential deadlock issues.
> 
> Ye Bin (3):
>  mm/vmscan: introduce drop_sb_dentry_inode() helper
>  sysctl: add support for drop_caches for individual filesystem
>  Documentation: add instructions for using 'drop_fs_caches sysctl'
>    sysctl
> 
> Documentation/admin-guide/sysctl/vm.rst |  44 +++++++++
> fs/drop_caches.c                        | 125 ++++++++++++++++++++++++
> include/linux/mm.h                      |   1 +
> mm/internal.h                           |   3 +
> mm/shrinker.c                           |   4 +-
> mm/vmscan.c                             |  50 ++++++++++
> 6 files changed, 225 insertions(+), 2 deletions(-)
> 
> -- 
> 2.34.1
>