From owner-freebsd-current@FreeBSD.ORG Thu Feb 5 09:03:35 2015 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 57417CA6; Thu, 5 Feb 2015 09:03:35 +0000 (UTC) Received: from kib.kiev.ua (kib.kiev.ua [IPv6:2001:470:d5e7:1::1]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id D3DAEA07; Thu, 5 Feb 2015 09:03:34 +0000 (UTC) Received: from tom.home (kostik@localhost [127.0.0.1]) by kib.kiev.ua (8.14.9/8.14.9) with ESMTP id t1593OEk034937 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Thu, 5 Feb 2015 11:03:25 +0200 (EET) (envelope-from kostikbel@gmail.com) DKIM-Filter: OpenDKIM Filter v2.9.2 kib.kiev.ua t1593OEk034937 Received: (from kostik@localhost) by tom.home (8.14.9/8.14.9/Submit) id t1593OPp034936; Thu, 5 Feb 2015 11:03:24 +0200 (EET) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: tom.home: kostik set sender to kostikbel@gmail.com using -f Date: Thu, 5 Feb 2015 11:03:24 +0200 From: Konstantin Belousov To: Alfred Perlstein Subject: Re: Weird behavior writing to SSD on 2013 MacBook Message-ID: <20150205090324.GI42409@kib.kiev.ua> References: <54D2C3DA.4060205@freebsd.org> <54D319EA.5020709@freebsd.org> <20150205083035.GF42409@kib.kiev.ua> <54D32DC3.6020409@mu.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <54D32DC3.6020409@mu.org> User-Agent: Mutt/1.5.23 (2014-03-12) X-Spam-Status: No, score=-2.0 required=5.0 tests=ALL_TRUSTED,BAYES_00, DKIM_ADSP_CUSTOM_MED,FREEMAIL_FROM,NML_ADSP_CUSTOM_MED autolearn=no autolearn_force=no version=3.4.0 X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on tom.home Cc: FreeBSD Current , Dimitry Andric , "Lundberg, Johannes" , Allan Jude X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 05 Feb 2015 09:03:35 -0000 On Thu, Feb 05, 2015 at 12:45:55AM -0800, Alfred Perlstein wrote: > > > On 2/5/15 12:30 AM, Konstantin Belousov wrote: > > On Thu, Feb 05, 2015 at 08:56:59AM +0100, Dimitry Andric wrote: > >> If you let bsdtar continue, and press control-T a few times, does the > >> user time (u) increase at all? Does it ever go any further, if you let > >> it run for a very long time? > >> > >> I believe a problem may have been introduced by r277922, leading to > >> filesystem hangs in some scenarios. It looks like this commit is also > >> in dumbbell's github fork: > >> > >> https://github.com/dumbbell/freebsd/commit/83723416a6bb8695d60c6573722a81086899f521 > >> > > > > Would be nice if you mailed me with your findings. > > > > Please try this. > > > > diff --git a/sys/ufs/ffs/ffs_softdep.c b/sys/ufs/ffs/ffs_softdep.c > > index 79783c8..700854e 100644 > > --- a/sys/ufs/ffs/ffs_softdep.c > > +++ b/sys/ufs/ffs/ffs_softdep.c > > @@ -1393,7 +1393,7 @@ softdep_flush(addr) > > VFSTOUFS(mp)->softdep_jblocks->jb_suspended)) > > kthread_suspend_check(); > > ACQUIRE_LOCK(ump); > > - while ((ump->softdep_flags & (FLUSH_CLEANUP | FLUSH_EXIT)) == 0) > > + if ((ump->softdep_flags & (FLUSH_CLEANUP | FLUSH_EXIT)) == 0) > > msleep(&ump->softdep_flushtd, LOCK_PTR(ump), PVM, > > "sdflush", hz / 2); > > ump->softdep_flags &= ~FLUSH_CLEANUP; > > @@ -1423,10 +1423,9 @@ worklist_speedup(mp) > > > > ump = VFSTOUFS(mp); > > LOCK_OWNED(ump); > > - if ((ump->softdep_flags & (FLUSH_CLEANUP | FLUSH_EXIT)) == 0) { > > + if ((ump->softdep_flags & (FLUSH_CLEANUP | FLUSH_EXIT)) == 0) > > ump->softdep_flags |= FLUSH_CLEANUP; > > - wakeup(&ump->softdep_flushtd); > > - } > > + wakeup(&ump->softdep_flushtd); > > } > > > > static int > > @@ -1471,11 +1470,10 @@ softdep_speedup(ump) > > TAILQ_INSERT_TAIL(&softdepmounts, sdp, sd_next); > > FREE_GBLLOCK(&lk); > > if ((altump->softdep_flags & > > - (FLUSH_CLEANUP | FLUSH_EXIT)) == 0) { > > + (FLUSH_CLEANUP | FLUSH_EXIT)) == 0) > > altump->softdep_flags |= FLUSH_CLEANUP; > > - altump->um_softdep->sd_cleanups++; > > - wakeup(&altump->softdep_flushtd); > > - } > > + altump->um_softdep->sd_cleanups++; > > + wakeup(&altump->softdep_flushtd); > > FREE_LOCK(altump); > > } > > } > > _______________________________________________ > > Why the conversion of while() to if()? > > > The reason for a while() when doing msleep/wakeup is typically to > prevent superfluous wakeups from signalling early. if()->while() was one of the changes in r277922, and I suspect that it is the cause of the issue. I.e. my thought right now is that softdep_process_worklist() does not keep up with the requests. If this is true, then real fix is somewhere else, but restoring pre-r277922 behaviour should get rid of immediate pain.