From: Al Viro <viro@ZenIV.linux.org.uk>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Mimi Zohar <zohar@linux.vnet.ibm.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
". James Morris" <jmorris@namei.org>,
linux-security-module@vger.kernel.org,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: deferring __fput()
Date: Sun, 24 Jun 2012 11:09:08 +0100 [thread overview]
Message-ID: <20120624100908.GR14083@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20120624041652.GN14083@ZenIV.linux.org.uk>
On Sun, Jun 24, 2012 at 05:16:52AM +0100, Al Viro wrote:
> We could, in principle, add a "ok_late" argument, allowing to add after
> PF_EXITING has been set only if it's true and run the list twice, but
> that's really more convoluted than I would like...
>
> Comments?
OK... What I had in mind is (modulo really dire need of saner commit messages
and probably a different ordering/splitup of the first 3 commits) is
in vfs.git#untested. WARNING: the branch name is no joke; it builds, but
I hadn't even tried to boot the resulting kernel yet.
Comments would be very welcome. It should get us the situation when
* __fput() is always called with no locks held by caller and
can take any locks whatsoever.
* fput() is legal to call from any contexts
* fput() done by a syscall will be completed before the process
returns to userland or terminates
* no extra context switches, unless we have the final fput() done
from interrupt (instant death on the current kernel) or from the
kernel thread.
* SCM_RIGHTS datagram destruction should be no worse than it is now;
probably a bit kinder on stack, even... Again, no extra context switches.
* Neither struct file nor struct task_struct changed size.
* task_work and rcu_head are identical at that point; I'd appreciate
a better name (I ended up calling that sucker callback_head, defined in
types.h, with #define rcu_head callback_head next to it, to avoid global
rename from hell). I can live with two identical structs (and a union
of those two in a few places), but I really see no point in going that way.
next prev parent reply other threads:[~2012-06-24 10:09 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-22 12:44 deferring __fput() Mimi Zohar
2012-06-23 9:20 ` Al Viro
2012-06-23 19:45 ` Al Viro
2012-06-23 20:38 ` Oleg Nesterov
2012-06-23 21:01 ` Al Viro
2012-06-23 21:11 ` Al Viro
2012-06-24 4:16 ` Al Viro
2012-06-24 10:09 ` Al Viro [this message]
2012-06-24 16:54 ` Oleg Nesterov
2012-06-24 15:33 ` Oleg Nesterov
2012-06-25 6:03 ` Al Viro
2012-06-25 15:18 ` Oleg Nesterov
2012-06-27 18:37 ` [PATCH 0/4] Was: " Oleg Nesterov
2012-06-27 18:37 ` [PATCH 1/4] task_work: use the single-linked list to shrink sizeof(task_work) Oleg Nesterov
2012-06-27 18:37 ` [PATCH 2/4] task_work: don't rely on PF_EXITING Oleg Nesterov
2012-06-27 18:38 ` [PATCH 3/4] task_work: deal with task_work callbacks adding more work Oleg Nesterov
2012-06-27 18:38 ` [PATCH 4/4] task_work: kill task_work->data Oleg Nesterov
2012-06-27 19:05 ` Oleg Nesterov
2012-06-28 4:38 ` [PATCH 0/4] Was: deferring __fput() Al Viro
2012-06-28 16:22 ` Oleg Nesterov
2012-06-28 16:45 ` Oleg Nesterov
2012-06-30 6:24 ` Al Viro
2012-06-30 17:41 ` Oleg Nesterov
2012-06-29 5:30 ` Mimi Zohar
2012-06-29 8:33 ` Al Viro
2012-06-29 13:02 ` Mimi Zohar
2012-06-29 17:41 ` Al Viro
2012-06-29 21:38 ` Mimi Zohar
2012-06-29 23:56 ` Mimi Zohar
2012-06-30 5:02 ` Al Viro
2012-07-01 19:50 ` Mimi Zohar
2012-07-01 20:57 ` Al Viro
2012-07-02 1:46 ` Mimi Zohar
2012-07-02 3:43 ` Al Viro
2012-07-02 5:11 ` Al Viro
2012-07-02 11:49 ` Mimi Zohar
2012-07-02 12:02 ` Al Viro
2012-07-02 13:01 ` Mimi Zohar
2012-07-02 13:33 ` Al Viro
2012-07-02 14:50 ` Mimi Zohar
2012-08-21 13:05 ` [PATCH] task_work: add a scheduling point in task_work_run() Eric Dumazet
2012-08-21 20:37 ` Mimi Zohar
2012-08-21 21:32 ` Eric Dumazet
2012-08-22 3:13 ` Mimi Zohar
2012-08-22 5:27 ` Michael Wang
2012-08-22 5:38 ` Al Viro
2012-06-23 20:57 ` deferring __fput() Al Viro
2012-06-23 21:33 ` Al Viro
2012-06-24 15:20 ` Oleg Nesterov
2012-06-24 18:11 ` Oleg Nesterov
2012-06-25 12:03 ` Peter Zijlstra
2012-06-25 12:14 ` Al Viro
2012-06-25 13:19 ` Peter Zijlstra
2012-06-25 13:53 ` 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=20120624100908.GR14083@ZenIV.linux.org.uk \
--to=viro@zeniv.linux.org.uk \
--cc=jmorris@namei.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-security-module@vger.kernel.org \
--cc=oleg@redhat.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).