From: Theodore Ts'o <tytso@mit.edu>
To: Andreas Dilger <adilger@dilger.ca>
Cc: Laurent GUERBY <laurent@guerby.net>, Jan Kara <jack@suse.cz>,
"linux-ext4@vger.kernel.org" <linux-ext4@vger.kernel.org>,
"sage@redhat.com" <sage@redhat.com>,
Abaakouk Mehdi <sileht@sileht.net>,
Loic Dachary <loic@dachary.org>
Subject: Re: [PATCH] Remove ext4 xattr mbcache to fix CPU lockup when using ceph #107301
Date: Fri, 20 Nov 2015 23:22:08 -0500 [thread overview]
Message-ID: <20151121042208.GC350@thunk.org> (raw)
In-Reply-To: <DD9C7131-404D-4873-A240-349F4E34E2BD@dilger.ca>
On Fri, Nov 20, 2015 at 06:08:15PM -0700, Andreas Dilger wrote:
>
> I'm definitely not in favor of deleting mbcache entirely, just having the
> mount option to disable it in cases where it is known not to be useful,
> such as Ceph or Lustre backing stores that never have shared xattrs.
>
> In some cases mbcache can be useful, since it allows sharing xattrs
> between inodes.
>
> I thought you would update our patch to add the mount option to disable
> mbcache?
And better yet would be if there was a blacklist of Lustre and Ceph
xattr type/keys that will never have shared attrs, so that mbcache is
not used for those xattrs automatically, *without* using a mount
option. Can someone at least start help creating that list?
But yeah, a complete deletion of mbcache is a non-starter.
Regards,
- Ted
prev parent reply other threads:[~2015-11-21 4:22 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-20 9:43 [PATCH] Remove ext4 xattr mbcache to fix CPU lockup when using ceph #107301 Laurent GUERBY
2015-11-21 1:08 ` Andreas Dilger
2015-11-21 4:22 ` Theodore Ts'o [this message]
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