Date: Thu, 05 Feb 2015 00:45:55 -0800 From: Alfred Perlstein <bright@mu.org> To: Konstantin Belousov <kostikbel@gmail.com>, Dimitry Andric <dim@FreeBSD.org> Cc: FreeBSD Current <freebsd-current@freebsd.org>, "Lundberg, Johannes" <johannes@brilliantservice.co.jp>, Allan Jude <allanjude@freebsd.org> Subject: Re: Weird behavior writing to SSD on 2013 MacBook Message-ID: <54D32DC3.6020409@mu.org> In-Reply-To: <20150205083035.GF42409@kib.kiev.ua> References: <CAASDrV=d=7aGdsDzDxRS2aXW%2BtWijVmNWrCNSYLWrWWvgwYx6Q@mail.gmail.com> <54D2C3DA.4060205@freebsd.org> <CAASDrV=9zrG8mH0Cn770yJLG6cBxuFjBQthhcHB_q4e7Afthww@mail.gmail.com> <CAASDrVnY8RQV2C=k=_v=23VD%2BQcXYegm1SLQPXDULwfQQ1xsDA@mail.gmail.com> <54D319EA.5020709@freebsd.org> <CAASDrVmcOzQiNMhi5dukd4PEyGXV4_T71jh3E3DfaWjKWWWM6g@mail.gmail.com> <AF0781EF-50BD-4CAB-8FEC-6334EED6DACF@FreeBSD.org> <20150205083035.GF42409@kib.kiev.ua>
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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. -Alfred
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