[Devel] Re: [PATCH 2.6.19-rc3] VFS: per-sb dentry lru list

[Andrew Morton]

On Fri, 27 Oct 2006 18:05:50 +0400
Vasily Averin <vvs at sw.ru> wrote:

> Virtuozzo/OpenVZ linux kernel team has discovered that umount/remount can last
> for hours looping in shrink_dcache_sb() without much successes. Since during
> shrinking s_umount semaphore is taken lots of other unrelated operations like
> sync can stop working until shrink finished.

Did you consider altering shrink_dcache_sb() so that it holds onto
dcache_lock and moves all the to-be-pruned dentries onto a private list in
a single pass, then prunes them all outside the lock?