From: "Luis R. Rodriguez" <mcgrof@kernel.org>
To: nbroeking@me.com, Jakub Kicinski <jakub.kicinski@netronome.com>,
Linus Torvalds <torvalds@linux-foundation.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>,
Thomas Gleixner <tglx@linutronix.de>,
Greg KH <gregkh@linuxfoundation.org>,
mfuzzey@parkeon.com, "Eric W. Biederman" <ebiederm@xmission.com>,
Dmitry Torokhov <dmitry.torokhov@gmail.com>,
Daniel Wagner <wagi@monom.org>,
mcgrof@kernel.org, David Woodhouse <dwmw2@infradead.org>,
jewalt@lgsinnovations.com, rafal@milecki.pl,
Arend Van Spriel <arend.vanspriel@broadcom.com>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
"Li, Yi" <yi1.li@linux.intel.com>,
atull@kernel.org, Moritz Fischer <moritz.fischer@ettus.com>,
Petr Mladek <pmladek@suse.com>,
Johannes Berg <johannes.berg@intel.com>,
Emmanuel Grumbach <emmanuel.grumbach@intel.com>,
"Coelho, Luciano" <luciano.coelho@intel.com>,
Kalle Valo <kvalo@codeaurora.org>,
Andrew
Subject: Re: [PATCH 2/4] swait: add the missing killable swaits
Date: Thu, 29 Jun 2017 21:44:55 +0200 [thread overview]
Message-ID: <20170629194455.GR21846@wotan.suse.de> (raw)
In-Reply-To: <20170629194015.GQ21846@wotan.suse.de>
On Thu, Jun 29, 2017 at 09:40:15PM +0200, Luis R. Rodriguez wrote:
> On Thu, Jun 29, 2017 at 11:59:29AM -0700, Linus Torvalds wrote:
> > On Thu, Jun 29, 2017 at 11:33 AM, Davidlohr Bueso <dave@stgolabs.net> wrote:
> > > On Thu, 29 Jun 2017, Linus Torvalds wrote:
> > >
> > >> I actually think swait is pure garbage. Most users only wake up one
> > >> process anyway, and using swait for that is stupid. If you only wake
> > >> up one, you might as well just have a single process pointer, not a
> > >> wait list at all, and then use "wake_up_process()".
> > >
> > > But you still need the notion of a queue, even if you wake one task
> > > at a time... I'm probably missing your point here.
> >
> > The *reason* they wake up only one seems to be that there really is
> > just one. It's some per-cpu idle thread for kvm, and for RCU it's the
> > RCU workqueue thread.
> >
> > So the queue literally looks suspiciously pointless.
> >
> > But I might be wrong, and there can actually be multiple entries.
>
> Since this swake_up() --> swake_up_all() reportedly *fixed* the one wake up
> issue it would seem this does queue [0]. That said, I don't see any simple tests
> tools/testing/selftests/swait but then again we don't have test for regular
> waits either...
>
> [0] https://bugzilla.kernel.org/show_bug.cgi?id=195477
I should also note that the swake_up_all() should have only helped in cases where
3 cards were used, as if only 2 were used that should have been covered by just
the swake_up(). Unless of course I hear otherwise by the reporter, Nicolas or
from Jakub.
Luis
next prev parent reply other threads:[~2017-06-29 19:44 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-14 22:20 [PATCH 0/4] firmware: fix fallback mechanism by ignoring SIGCHLD Luis R. Rodriguez
2017-06-14 22:20 ` [PATCH 1/4] test_firmware: add test case for SIGCHLD on sync fallback Luis R. Rodriguez
2017-06-14 22:20 ` [PATCH 2/4] swait: add the missing killable swaits Luis R. Rodriguez
[not found] ` <20170614222017.14653-3-mcgrof-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2017-06-29 12:54 ` Greg KH
[not found] ` <20170629125402.GH26046-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>
2017-06-29 13:05 ` Thomas Gleixner
2017-06-29 13:35 ` Greg KH
2017-06-29 13:46 ` Thomas Gleixner
2017-06-29 16:13 ` Linus Torvalds
2017-06-29 16:31 ` Matthew Wilcox
2017-06-29 17:29 ` Luis R. Rodriguez
2017-06-29 17:40 ` Davidlohr Bueso
2017-06-29 17:57 ` Linus Torvalds
2017-06-29 18:33 ` Davidlohr Bueso
[not found] ` <20170629183339.GD3954-3dK4OQgjB4rH06JGZaSw0A@public.gmane.org>
2017-06-29 18:59 ` Linus Torvalds
[not found] ` <CA+55aFz8Mhx+A-g-5yOG-O1ZLRUR_fpeeA4iBNGH8EnDBZEdpA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-06-29 19:40 ` Luis R. Rodriguez
2017-06-29 19:44 ` Luis R. Rodriguez [this message]
[not found] ` <20170629194455.GR21846-B4tOwbsTzaBolqkO4TVVkw@public.gmane.org>
2017-06-29 20:58 ` Jakub Kicinski
2017-06-29 22:50 ` Luis R. Rodriguez
2017-06-29 22:53 ` Jakub Kicinski
2017-06-29 23:00 ` Luis R. Rodriguez
2017-06-29 23:06 ` Jakub Kicinski
[not found] ` <20170629225003.GU21846-B4tOwbsTzaBolqkO4TVVkw@public.gmane.org>
2017-07-12 21:33 ` Luis R. Rodriguez
[not found] ` <20170629194015.GQ21846-B4tOwbsTzaBolqkO4TVVkw@public.gmane.org>
2017-06-29 20:57 ` Linus Torvalds
2017-07-05 2:06 ` Davidlohr Bueso
[not found] ` <20170705020635.GD11168-3dK4OQgjB4rH06JGZaSw0A@public.gmane.org>
2017-07-07 19:58 ` Linus Torvalds
2017-07-07 22:27 ` Davidlohr Bueso
2017-07-07 22:48 ` Linus Torvalds
2017-06-29 19:15 ` Marcelo Tosatti
[not found] ` <20170629191506.GB12368-I4X2Mt4zSy4@public.gmane.org>
2017-06-30 4:03 ` Linus Torvalds
2017-06-30 11:55 ` Marcelo Tosatti
2017-06-30 11:57 ` Marcelo Tosatti
2017-06-30 17:30 ` Krister Johansen
2017-06-14 22:20 ` [PATCH 3/4] firmware: avoid invalid fallback aborts by using killable swait Luis R. Rodriguez
2017-06-14 22:20 ` [PATCH 4/4] firmware: send -EINTR on signal abort on fallback mechanism Luis R. Rodriguez
2017-06-15 7:49 ` [PATCH 0/4] firmware: fix fallback mechanism by ignoring SIGCHLD Martin Fuzzey
[not found] ` <20170614222017.14653-1-mcgrof-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2017-06-26 21:19 ` Luis R. Rodriguez
2017-06-29 15:14 ` Greg KH
[not found] ` <20170629151442.GA4880-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>
2017-06-29 17:29 ` Luis R. Rodriguez
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