From: Arnd Bergmann <arnd@arndb.de>
To: Alex Shi <alex.shi@intel.com>
Cc: tglx@linutronix.com, "mingo@redhat.com" <mingo@redhat.com>,
hpa@zytor.com, akpm@linux-foundation.org,
linux-kernel@vger.kernel.org, x86@kernel.org,
andi.kleen@intel.com
Subject: Re: [RFC patch] spindep: add cross cache lines checking
Date: Mon, 5 Mar 2012 09:41:56 +0000 [thread overview]
Message-ID: <201203050941.56502.arnd@arndb.de> (raw)
In-Reply-To: <1330926234.18835.51.camel@debian>
On Monday 05 March 2012, Alex Shi wrote:
> Subject: [PATCH] lockdep: add cross cache lines checking
>
> Modern x86 CPU won't hold whole memory bus when executing 'lock'
> prefixed instructions unless the instruction destination is crossing 2
> cache lines. If so, it is disaster of system performance.
>
> Actually if the lock is not in the 'packed' structure, gcc places it
> safely under x86 arch. But seems add this checking in
> CONFIG_DEBUG_LOCK_ALLOC is harmless.
Have you tried making this a compile-time check using __alignof__?
I would say that any spinlock in a packed data structure is
basically a bug, even more so on most other architectures besides
x86.
Arnd
next prev parent reply other threads:[~2012-03-05 10:21 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-05 3:20 [RFC patch] spin_lock: add cross cache lines checking Alex Shi
2012-03-05 3:24 ` Alex Shi
2012-03-05 5:43 ` [RFC patch] spindep: " Alex Shi
2012-03-05 5:48 ` Alex Shi
2012-03-05 9:41 ` Arnd Bergmann [this message]
2012-03-05 10:43 ` Ingo Molnar
2012-03-06 6:13 ` Alex Shi
2012-03-06 6:18 ` Alex Shi
2012-03-06 9:32 ` Arnd Bergmann
2012-03-07 8:23 ` Alex Shi
2012-03-07 11:54 ` Arnd Bergmann
2012-03-07 13:13 ` Alex Shi
2012-03-07 13:39 ` Ingo Molnar
2012-03-08 2:21 ` Alex Shi
2012-03-08 7:13 ` Ingo Molnar
2012-03-09 1:20 ` Alex Shi
2012-03-08 2:30 ` Alex Shi
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