From: Miklos Szeredi <miklos@szeredi.hu>
To: Steven Whitehouse <swhiteho@redhat.com>
Cc: David Howells <dhowells@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Al Viro <viro@zeniv.linux.org.uk>, Karel Zak <kzak@redhat.com>,
Jeff Layton <jlayton@redhat.com>,
Miklos Szeredi <mszeredi@redhat.com>,
Nicolas Dichtel <nicolas.dichtel@6wind.com>,
Christian Brauner <christian@brauner.io>,
Lennart Poettering <lennart@poettering.net>,
Linux API <linux-api@vger.kernel.org>,
Ian Kent <raven@themaw.net>,
LSM <linux-security-module@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: file metadata via fs API
Date: Wed, 12 Aug 2020 12:04:14 +0200 [thread overview]
Message-ID: <CAJfpeguMjU+n-JXE6aUQQGeMpCS4bsy4HQ37NHJ8aD8Aeg2qhA@mail.gmail.com> (raw)
In-Reply-To: <d2d179c7-9b60-ca1a-0c9f-d308fc7af5ce@redhat.com>
On Wed, Aug 12, 2020 at 11:43 AM Steven Whitehouse <swhiteho@redhat.com> wrote:
>
> Hi,
>
> On 12/08/2020 09:37, Miklos Szeredi wrote:
> [snip]
> >
> > b) The awarded performance boost is not warranted for the use cases it
> > is designed for.
>
> This is a key point. One of the main drivers for this work is the
> efficiency improvement for large numbers of mounts. Ian and Karel have
> already provided performance measurements showing a significant benefit
> compared with what we have today. If you want to propose this
> alternative interface then you need to show that it can sustain similar
> levels of performance, otherwise it doesn't solve the problem. So
> performance numbers here would be helpful.
Definitely. Will measure performance with the interface which Linus proposed.
I'm not worried, though; the problem with the previous interface was
that it resulted in the complete mount table being re-parsed on each
individual event resulting in quadratic behavior. This doesn't affect
any interface that can query individual mount/superblock objects.
> Also - I may have missed this earlier in the discussion, what are the
> atomicity guarantees with this proposal? This is the other key point for
> the API, so it would be good to see that clearly stated (i.e. how does
> one use it in combination with the notifications to provide an up to
> date, consistent view of the kernel's mounts)
fsinfo(2) provides version counters on mount and superblock objects to
verify consistency of returned data, since not all data is returned in
a single call. Same method could be used with the open/read based
interface to verify consistency in case multiple attributes/attribute
groups need to be queried.
Thanks,
Miklos
next prev parent reply other threads:[~2020-08-12 10:04 UTC|newest]
Thread overview: 89+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-03 15:27 [GIT PULL] Mount notifications David Howells
2020-08-03 15:49 ` [GIT PULL] Filesystem Information David Howells
2020-08-03 16:42 ` Miklos Szeredi
2020-08-04 2:15 ` Ian Kent
2020-08-04 14:36 ` Miklos Szeredi
2020-08-05 1:33 ` Ian Kent
2020-08-05 8:00 ` Miklos Szeredi
2020-08-05 11:13 ` Ian Kent
2020-08-05 8:24 ` file metadata via fs API (was: [GIT PULL] Filesystem Information) Miklos Szeredi
2020-08-11 13:54 ` Miklos Szeredi
2020-08-11 14:08 ` Al Viro
2020-08-11 14:22 ` Miklos Szeredi
2020-08-11 14:31 ` Al Viro
[not found] ` <CAAgocE07=vVKpQhG+rjEGO=NEBKZ02gjg4TRPxECAc+RKrzn=Q@mail.gmail.com>
2020-08-11 14:36 ` Al Viro
2020-08-11 14:36 ` Miklos Szeredi
2020-08-11 14:42 ` Al Viro
2020-08-11 14:47 ` Miklos Szeredi
2020-08-11 15:20 ` Linus Torvalds
2020-08-11 15:30 ` Miklos Szeredi
2020-08-11 16:05 ` Linus Torvalds
2020-08-11 18:49 ` Miklos Szeredi
2020-08-11 19:31 ` Lennart Poettering
2020-08-11 19:50 ` Christian Brauner
2020-08-11 19:39 ` Christian Brauner
2020-08-12 0:53 ` Ian Kent
2020-08-11 15:39 ` Andy Lutomirski
2020-08-11 16:17 ` Casey Schaufler
2020-08-11 16:30 ` Linus Torvalds
2020-08-11 20:28 ` Miklos Szeredi
2020-08-11 20:36 ` Jann Horn
2020-08-11 20:56 ` Miklos Szeredi
2020-08-11 21:17 ` Andy Lutomirski
2020-08-11 21:18 ` Linus Torvalds
2020-08-12 7:23 ` Miklos Szeredi
2020-08-12 14:39 ` Al Viro
2020-08-12 14:46 ` Miklos Szeredi
2020-08-12 15:08 ` Al Viro
2020-08-12 15:13 ` Miklos Szeredi
2020-08-12 16:33 ` Al Viro
2020-08-12 17:16 ` Miklos Szeredi
2020-08-12 17:39 ` Al Viro
2020-08-12 18:33 ` Al Viro
2020-08-12 21:30 ` Al Viro
2020-08-18 9:41 ` Miklos Szeredi
2020-08-18 9:30 ` Miklos Szeredi
2020-08-12 15:22 ` David Howells
2020-08-11 21:20 ` Al Viro
2020-08-11 21:35 ` Casey Schaufler
2020-08-11 16:05 ` Al Viro
2020-08-11 16:09 ` Linus Torvalds
2020-08-11 16:39 ` Al Viro
2020-08-12 10:14 ` Karel Zak
2020-08-12 13:09 ` Miklos Szeredi
2020-08-12 13:33 ` David Howells
2020-08-12 13:54 ` Miklos Szeredi
2020-08-12 0:05 ` David Howells
2020-08-12 7:55 ` Miklos Szeredi
2020-08-12 8:29 ` David Howells
2020-08-12 8:37 ` Miklos Szeredi
2020-08-12 9:43 ` file metadata via fs API Steven Whitehouse
2020-08-12 10:04 ` Miklos Szeredi [this message]
2020-08-12 11:28 ` Karel Zak
2020-08-12 12:43 ` Miklos Szeredi
2020-08-13 8:52 ` Karel Zak
2020-08-12 13:06 ` David Howells
2020-08-13 1:01 ` Ian Kent
2020-08-12 18:18 ` file metadata via fs API (was: [GIT PULL] Filesystem Information) Linus Torvalds
2020-08-12 19:34 ` file metadata via fs API Steven Whitehouse
2020-08-12 19:50 ` Linus Torvalds
2020-08-13 3:44 ` Ian Kent
2020-08-13 10:36 ` Karel Zak
2020-08-14 7:58 ` Lennart Poettering
2020-08-17 11:32 ` Steven Whitehouse
2020-08-17 17:15 ` Linus Torvalds
2020-08-17 22:44 ` Linus Torvalds
2020-08-18 12:50 ` Miklos Szeredi
2020-08-18 18:51 ` Linus Torvalds
2020-08-18 20:18 ` Miklos Szeredi
2020-08-18 20:53 ` Linus Torvalds
2020-08-21 13:17 ` Miklos Szeredi
2020-08-19 2:29 ` Al Viro
2020-08-13 3:53 ` file metadata via fs API (was: [GIT PULL] Filesystem Information) Jeffrey E Altman
2020-08-14 17:05 ` Linus Torvalds
2020-08-18 15:01 ` Jeffrey E Altman
2020-08-14 8:06 ` Lennart Poettering
2020-08-12 13:54 ` David Howells
2020-08-12 14:10 ` Miklos Szeredi
2020-08-12 14:23 ` David Howells
2020-08-03 22:48 ` [GIT PULL] Mount notifications Ian Kent
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