LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: David Howells <dhowells@redhat.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: dhowells@redhat.com, Andrew Morton <akpm@linux-foundation.org>,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	Jiri Pirko <jpirko@redhat.com>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Peter Zijlstra <peterz@infradead.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC,PATCH] workqueues: turn queue_work() into the "barrier" for work->func()
Date: Tue, 11 Nov 2008 22:46:21 +0000	[thread overview]
Message-ID: <9266.1226443581@redhat.com> (raw)
In-Reply-To: <20081111203324.GA30425@redhat.com>

Oleg Nesterov <oleg@redhat.com> wrote:

> I think the caller of queue_work() has all rights to expect that
> the next invocation of work_func() must see "VAR == 1", but this
> is not true if the work is already pending.

As you said, queue_work() does test_and_set_bit() which implies smp_mb()
either side of the function, so you're half way there, and run_workqueue()
calls spin_unlock_irq() just before calling work_clear_pending()...  So might
it make sense to move the work_clear_pending() into locked section?  Or would
that require an smp_mb__before_clear_bit()?

David

  reply	other threads:[~2008-11-11 22:47 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-11-11 20:33 Oleg Nesterov
2008-11-11 22:46 ` David Howells [this message]
2008-11-12 11:58   ` Oleg Nesterov

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=9266.1226443581@redhat.com \
    --to=dhowells@redhat.com \
    --cc=akpm@linux-foundation.org \
    --cc=dmitry.torokhov@gmail.com \
    --cc=jpirko@redhat.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=oleg@redhat.com \
    --cc=paulmck@linux.vnet.ibm.com \
    --cc=peterz@infradead.org \
    --subject='Re: [RFC,PATCH] workqueues: turn queue_work() into the "barrier" for work->func()' \
    /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

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).