From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] [ARM] Do not call flush_cache_user_range with mmap_sem held
Date: Tue, 4 May 2010 08:40:57 +0100 [thread overview]
Message-ID: <20100504074057.GA18062@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <AANLkTilY5V-QkPtrp6csEsz5geT10P_RyeHk3rmnrdAZ@mail.gmail.com>
On Mon, May 03, 2010 at 09:07:03PM -0700, Dima Zavin wrote:
> >> The point of this code is to first validate that the region we're working
> >> on is valid. ?As soon as we drop the lock, we lose the guarantee that
> >> the region is valid while we operate on it - indeed, the region could be
> >> unmapped and remapped by a different thread.
> >
> > So what if it was remapped? The worst case scenario in this case is
> > that we needlessly flush a region of memory, but its not "wrong". It
> > can't be any worse than just doing a full cache flush. If another
> > thread unmapped the region, then we should (and will) segfault the
> > flushing thread, which is the correct behavior IMHO.
>
> ping.
I still do not think this is a good idea for the reasons I've already
mentioned.
next prev parent reply other threads:[~2010-05-04 7:40 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-28 7:32 [PATCH] [ARM] Do not call flush_cache_user_range with mmap_sem held Dima Zavin
2010-04-28 7:35 ` Dima Zavin
2010-04-29 13:00 ` Russell King - ARM Linux
2010-04-29 18:16 ` Jamie Lokier
2010-04-29 18:24 ` Russell King - ARM Linux
2010-04-29 19:23 ` Dima Zavin
2010-05-04 4:07 ` Dima Zavin
2010-05-04 7:40 ` Russell King - ARM Linux [this message]
2010-05-06 15:00 ` [PATCH] [ARM] Do not call flush_cache_user_range with mmap_semheld Catalin Marinas
2010-05-06 16:01 ` Jamie Lokier
2010-05-06 16:07 ` Jamie Lokier
2010-05-06 16:24 ` Catalin Marinas
2010-05-06 16:21 ` Catalin Marinas
2010-05-06 15:08 ` [PATCH] [ARM] Do not call flush_cache_user_range with mmap_sem held Catalin Marinas
-- strict thread matches above, loose matches on Subject: below --
2011-11-07 17:33 [PATCH] ARM: " Catalin Marinas
2011-11-16 21:23 ` Olof Johansson
2011-11-16 23:50 ` Russell King - ARM Linux
2011-11-17 0:16 ` Olof Johansson
2011-11-17 0:20 ` Olof Johansson
2011-11-17 10:26 ` Catalin Marinas
2011-11-17 10:49 ` Russell King - ARM Linux
2011-11-17 10:45 ` Russell King - ARM Linux
2011-11-20 17:54 ` Olof Johansson
2011-11-17 10:22 ` Catalin Marinas
2011-11-17 10:42 ` Russell King - ARM Linux
2011-11-17 10:59 ` Catalin Marinas
2011-11-17 11:03 ` Russell King - ARM Linux
2011-11-17 11:25 ` Catalin Marinas
2012-04-09 5:58 ` Dirk Behme
2012-04-09 14:24 ` Olof Johansson
2012-04-10 17:17 ` Will Deacon
2012-04-18 15:05 ` Will Deacon
2012-04-18 15:27 ` Russell King - ARM Linux
2012-04-18 16:27 ` Will Deacon
2012-04-18 17:15 ` Catalin Marinas
2012-04-18 8:40 ` Catalin Marinas
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