From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail-gx0-f174.google.com ([209.85.161.174]:57585 "EHLO mail-gx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751048Ab1KASGI (ORCPT ); Tue, 1 Nov 2011 14:06:08 -0400 Date: Tue, 1 Nov 2011 11:06:01 -0700 From: Tejun Heo To: Oleg Nesterov Cc: Jeff Layton , "Rafael J. Wysocki" , Steve French , linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, linux-cifs@vger.kernel.org, "J. Bruce Fields" , Neil Brown , trond.myklebust@netapp.com, linux-nfs@vger.kernel.org Subject: Re: [RFC PATCH] freezer: revert 27920651fe "PM / Freezer: Make fake_signal_wake_up() wake TASK_KILLABLE tasks too" Message-ID: <20111101180601.GV18855@google.com> References: <20111031221743.GA18855@google.com> <201111010024.16659.rjw@sisk.pl> <20111031233059.GI18855@google.com> <20111101005505.GO18855@google.com> <20111101041337.39077229@tlielax.poochiereds.net> <20111101065958.50addab5@tlielax.poochiereds.net> <20111101163059.GR18855@google.com> <20111101175953.GB5358@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20111101175953.GB5358@redhat.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Tue, Nov 01, 2011 at 06:59:53PM +0100, Oleg Nesterov wrote: > > #define wait_event_freezekillable(wq, condition) \ > > do { \ > > DEFINE_WAIT(__wait); \ > > for (;;) { \ > > prepare_to_wait(&wq, &__wait, TASK_INTERRUPTIBLE); \ > > if (condition || fatal_signal_pending(current)) \ > > break; \ > > schedule(); \ > > No, this can't work, afaics. > > Once the caller recieves a non-fatal signal (gets TIF_SIGPENDING), > schedule() won't block in TASK_INTERRUPTIBLE state. > > IOW, wait_event_freezekillable() becomes a busy-wait loop. Yeah yeah, Trond already pointed it out. I forgot about the sigpending special case in schedule(), which I think is rather odd, oh well. Any better ideas? -- tejun