From: Al Viro <viro@ZenIV.linux.org.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-fsdevel@vger.kernel.org, James Morris <jmorris@namei.org>,
linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org,
David Safford <safford@linux.vnet.ibm.com>,
Dmitry Kasatkin <dmitry.kasatkin@intel.com>,
Mimi Zohar <zohar@linux.vnet.ibm.com>,
David Miller <davem@davemloft.net>
Subject: Re: [RFC] situation with fput() locking (was Re: [PULL REQUEST] : ima-appraisal patches)
Date: Fri, 20 Apr 2012 17:08:48 +0100 [thread overview]
Message-ID: <20120420160848.GG6871@ZenIV.linux.org.uk> (raw)
In-Reply-To: <CA+55aFxia+u3VAf0qN-2wv7DyAQZK-Z8=n=cqUvo--+C905aFg@mail.gmail.com>
On Fri, Apr 20, 2012 at 08:56:57AM -0700, Linus Torvalds wrote:
> > We also get something else out of that - AFAICS, the kludge in __scm_destroy()
> > can be killed after that. ?We did it to prevent recursion on fput(), right?
> > Now that recursion will be gone...
>
> Hmm.. That points out that we may have a *lot* of these pending final
> fput's, though. So the deferral queueing should be fairly light. What
> were your particular plans for it?
Doing removal from per-sb list immediately (i.e. before possible
deferral; we skip ones with zero ->f_count when we walk the list
anyway), then in case we decide to defer just move them to per-CPU
list and schedule work on that CPU, with handler that will pull the
corresponding list out and do the rest of __fput() for everything
in that list. No extra locking, just preempt_disable() around the
"move to per-CPU list" bit. Or a per-CPU spinlock with worker not
being tied to specific CPU and told which CPU's list to work with.
How does CPU hotplug interact with work scheduled on CPU about to
be taken down, BTW?
next prev parent reply other threads:[~2012-04-20 16:08 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-18 13:04 [PULL REQUEST] : ima-appraisal patches Mimi Zohar
2012-04-18 15:02 ` James Morris
2012-04-18 18:07 ` Mimi Zohar
2012-04-18 18:39 ` Al Viro
2012-04-18 20:56 ` Mimi Zohar
2012-04-19 19:57 ` Mimi Zohar
2012-04-20 0:43 ` [RFC] situation with fput() locking (was Re: [PULL REQUEST] : ima-appraisal patches) Al Viro
2012-04-20 2:31 ` Linus Torvalds
2012-04-20 2:54 ` Al Viro
2012-04-20 2:58 ` Linus Torvalds
2012-04-20 8:09 ` Al Viro
2012-04-20 15:56 ` Linus Torvalds
2012-04-20 16:08 ` Al Viro [this message]
2012-04-20 16:42 ` Al Viro
2012-04-20 17:21 ` Linus Torvalds
2012-04-20 18:07 ` Al Viro
2012-04-20 3:15 ` Al Viro
2012-04-20 18:54 ` Hugh Dickins
2012-04-20 19:04 ` Al Viro
2012-04-20 19:18 ` Linus Torvalds
2012-04-20 19:32 ` Hugh Dickins
2012-04-20 19:58 ` Al Viro
2012-04-20 21:12 ` Linus Torvalds
2012-04-20 22:13 ` Al Viro
2012-04-20 22:35 ` Linus Torvalds
2012-04-27 7:35 ` Kasatkin, Dmitry
2012-04-27 17:34 ` Al Viro
2012-04-27 18:52 ` Kasatkin, Dmitry
2012-04-27 19:15 ` Kasatkin, Dmitry
2012-04-30 14:32 ` Mimi Zohar
2012-05-03 4:23 ` James Morris
2012-04-20 19:37 ` Al Viro
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20120420160848.GG6871@ZenIV.linux.org.uk \
--to=viro@zeniv.linux.org.uk \
--cc=davem@davemloft.net \
--cc=dmitry.kasatkin@intel.com \
--cc=jmorris@namei.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-security-module@vger.kernel.org \
--cc=safford@linux.vnet.ibm.com \
--cc=torvalds@linux-foundation.org \
--cc=zohar@linux.vnet.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).