From: Michael Leun <lkml20130126@newton.leun.net>
To: Colin Cross <ccross@android.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>,
Linus Torvalds <torvalds@linux-foundation.org>,
lkml <linux-kernel@vger.kernel.org>, Pavel Machek <pavel@ucw.cz>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Mandeep Singh Baines <msb@chromium.org>,
Oleg Nesterov <oleg@redhat.com>,
linux-nfs <linux-nfs@vger.kernel.org>,
Linux PM list <linux-pm@vger.kernel.org>,
netdev <netdev@vger.kernel.org>, Tejun Heo <tj@kernel.org>,
Darren Hart <dvhart@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Randy Dunlap <rdunlap@infradead.org>,
Al Viro <viro@zeniv.linux.org.uk>
Subject: Re: 3.11-rc regression bisected: s2disk does not work (was Re: [PATCH v3 13/16] futex: use freezable blocking call)
Date: Tue, 23 Jul 2013 23:58:27 +0200 [thread overview]
Message-ID: <20130723235827.014f7899@xenia.leun.net> (raw)
In-Reply-To: <CAMbhsRSRcQ-CgCTkRGJJSVSArPqmGRjgxeRBUY0zE94Osxa-nA@mail.gmail.com>
On Tue, 23 Jul 2013 13:31:49 -0700
Colin Cross <ccross@android.com> wrote:
> On Mon, Jul 22, 2013 at 11:28 PM, Colin Cross <ccross@android.com>
> wrote:
> > On Mon, Jul 22, 2013 at 6:41 PM, Rafael J. Wysocki <rjw@sisk.pl>
> > wrote:
> >> On Monday, July 22, 2013 05:42:49 PM Colin Cross wrote:
> >>> On Mon, Jul 22, 2013 at 5:32 PM, Linus Torvalds
> >>> <torvalds@linux-foundation.org> wrote:
> >>> > On Mon, Jul 22, 2013 at 4:55 PM, Colin Cross
> >>> > <ccross@android.com> wrote:
> >>> >>
> >>> >> I think the right solution is to add a flag to the freezing
> >>> >> task that marks it unfreezable. I think PF_NOFREEZE would
> >>> >> work, although it is normally used on kernel threads, can you
> >>> >> see if the attached patch helps?
> >>> >
> >>> > Hmm. That does seem to be the right thing to do, but I wonder
> >>> > about the *other* callers of freeze_processes() IOW, kexec and
> >>> > friends.
> >>> >
> >>> > So maybe we should do this in {freeze|thaw}_processes() itself,
> >>> > and just make the rule be that the caller of freeze_processes()
> >>> > itself is obviously not frozen, and has to be the same one that
> >>> > then thaws things?
> >>> >
> >>> > Colin? Rafael? Comments?
> >>> >
> >>> > Linus
> >>>
> >>> I was worried about clearing the flag in thaw_processes(). If a
> >>> kernel thread with PF_NOFREEZE set ever called thaw_processes(),
> >>> which autosleep might do, it would clear the flag. Or if a
> >>> different thread called freeze_processes() and thaw_processes().
> >>
> >> Is that legitimate?
> >
> > Nothing precludes it today, but I don't see any need for it. I'll
> > add a comment when I add the flag.
> >
> >>> All the other callers besides the SNAPSHOT_FREEZE ioctl stay in
> >>> the kernel between freeze_processes() and thaw_processes(), which
> >>> makes the fanout of places that could call try_to_freeze() much
> >>> more controllable.
> >>>
> >>> Using a new flag that operates like PF_NOFREEZE but doesn't
> >>> conflict with it, or a nofreeze_depth counter, would also work.
> >>
> >> Well, that would be robust enough. At least if the purpose of
> >> that new flag is clearly specified, people hopefully won't be
> >> tempted to optimize it away in the future.
> >>
> >> Thanks,
> >> Rafael
> >
> > OK, I'll add a new flag.
>
>
> Michael, can you see if this patch works and doesn't throw any
> warnings during suspend or resume?
Tried several times with and without threads = y in suspend.conf, tried
also to produce high load / much processes / high memory usage.
Worked every time, no WARN seen.
> If the extra process flag is considered too precious for this
> (there are only 2 left after this patch) I could get the
> same functionality by having freeze_processes() reject calls
> from a PF_KTHREAD|PF_NOFREEZE thread, and use PF_KTHREAD to
> determine if PF_NOFREEZE should be cleared in thaw_processes().
If another solution is considered please do not hesitate to send me the
patch for another round of check.
--
MfG,
Michael Leun
next prev parent reply other threads:[~2013-07-23 21:58 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-06 23:50 [PATCH v2 00/10] optimize freezing tasks by reducing task wakeups Colin Cross
2013-05-06 23:50 ` [PATCH v3 01/16] freezer: add unsafe versions of freezable helpers for NFS Colin Cross
2013-05-06 23:50 ` [PATCH v3 02/16] freezer: add unsafe versions of freezable helpers for CIFS Colin Cross
2013-05-07 10:07 ` Jeff Layton
[not found] ` <20130507060730.03364687-9yPaYZwiELC+kQycOl6kW4xkIHaj4LzF@public.gmane.org>
2013-05-07 17:47 ` Colin Cross
[not found] ` <CAMbhsRQ1i_dFctwjkqjg3=GJdEc8ReEDk=NnEFEXj8u3MaEqDA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-05-07 17:52 ` [PATCH v4 " Colin Cross
[not found] ` <1367949125-21809-1-git-send-email-ccross-z5hGa2qSFaRBDgjK7y7TUQ@public.gmane.org>
2013-05-07 18:11 ` Jeff Layton
[not found] ` <1367884221-20462-3-git-send-email-ccross-z5hGa2qSFaRBDgjK7y7TUQ@public.gmane.org>
2013-05-07 12:28 ` [PATCH v3 " Pavel Machek
2013-05-06 23:50 ` [PATCH v3 03/16] lockdep: remove task argument from debug_check_no_locks_held Colin Cross
2013-05-07 12:28 ` Pavel Machek
2013-05-06 23:50 ` [PATCH v3 04/16] lockdep: check that no locks held at freeze time Colin Cross
[not found] ` <1367884221-20462-5-git-send-email-ccross-z5hGa2qSFaRBDgjK7y7TUQ@public.gmane.org>
2013-05-07 12:29 ` Pavel Machek
[not found] ` <1367884221-20462-1-git-send-email-ccross-z5hGa2qSFaRBDgjK7y7TUQ@public.gmane.org>
2013-05-06 23:50 ` [PATCH v3 05/16] freezer: shorten freezer sleep time using exponential backoff Colin Cross
2013-05-06 23:50 ` [PATCH v3 06/16] freezer: skip waking up tasks with PF_FREEZER_SKIP set Colin Cross
2013-05-06 23:50 ` [PATCH v3 07/16] freezer: convert freezable helpers to freezer_do_not_count() Colin Cross
2013-05-06 23:50 ` [PATCH v3 08/16] freezer: convert freezable helpers to static inline where possible Colin Cross
2013-05-06 23:50 ` [PATCH v3 09/16] freezer: add new freezable helpers using freezer_do_not_count() Colin Cross
2013-05-06 23:50 ` [PATCH v3 10/16] binder: use freezable blocking calls Colin Cross
2013-05-06 23:50 ` [PATCH v3 11/16] epoll: use freezable blocking call Colin Cross
2013-05-06 23:50 ` [PATCH v3 12/16] select: " Colin Cross
2013-05-06 23:50 ` [PATCH v3 13/16] futex: " Colin Cross
2013-07-22 23:02 ` 3.11-rc regression bisected: s2disk does not work (was Re: [PATCH v3 13/16] futex: use freezable blocking call) Michael Leun
2013-07-22 23:55 ` Colin Cross
2013-07-23 0:32 ` Linus Torvalds
[not found] ` <CA+55aFzUVPJe96z8V0F-znc8ZcpJid7LEeYww80M-Mx=S91tAA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-07-23 0:42 ` Colin Cross
[not found] ` <CAMbhsRReF9xB597i9CcCj7D1P5kvB4cc0JmDQYeboqi11Kp99A-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-07-23 1:41 ` Rafael J. Wysocki
[not found] ` <15305281.aClQ8XUG9t-sKB8Sp2ER+y1GS7QM15AGw@public.gmane.org>
2013-07-23 6:28 ` Colin Cross
2013-07-23 20:31 ` Colin Cross
2013-07-23 21:58 ` Michael Leun [this message]
2013-07-23 18:08 ` Michael Leun
2013-07-23 18:24 ` Darren Hart
2013-07-23 18:29 ` Colin Cross
2013-07-23 19:16 ` Michael Leun
[not found] ` <20130723211622.50f75087-gjVD6BTPoEbYa4IuQwzu8g@public.gmane.org>
2013-07-23 19:29 ` Colin Cross
[not found] ` <CAMbhsRQU=TswYg-2WqHmzt-_GpfMFpYHPSU4eFd5XMw7DRGXJA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-07-23 19:58 ` Michael Leun
[not found] ` <CAMbhsRT6zOKLhG_uh=nA8H_3d7afhG+4jvWjvidY3fEguryP_Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-07-23 21:43 ` Rafael J. Wysocki
[not found] ` <20130723010250.5a3465ec-gjVD6BTPoEbYa4IuQwzu8g@public.gmane.org>
2013-07-23 0:26 ` Pavel Machek
2013-05-06 23:50 ` [PATCH v3 14/16] nanosleep: use freezable blocking call Colin Cross
2013-05-06 23:50 ` [PATCH v3 15/16] sigtimedwait: " Colin Cross
2013-05-06 23:50 ` [PATCH v3 16/16] af_unix: use freezable blocking calls in read Colin Cross
2013-05-07 18:12 ` [PATCH v2 00/10] optimize freezing tasks by reducing task wakeups Tejun Heo
2013-05-08 0:02 ` Rafael J. Wysocki
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