From: Peter Zijlstra <peterz@infradead.org>
To: Alexey Brodkin <Alexey.Brodkin@synopsys.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"linux-snps-arc@lists.infradead.org"
<linux-snps-arc@lists.infradead.org>,
"stable@vger.kernel.org" <stable@vger.kernel.org>,
"greg@kroah.com" <greg@kroah.com>,
"will.deacon@arm.com" <will.deacon@arm.com>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"David.Laight@ACULAB.COM" <David.Laight@ACULAB.COM>,
"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
"geert@linux-m68k.org" <geert@linux-m68k.org>
Subject: Re: [PATCH v3] devres: Explicitly align datai[] to 64-bit
Date: Mon, 9 Jul 2018 16:49:25 +0200 [thread overview]
Message-ID: <20180709144925.GU2476@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <44727d3cebda7bee5b68fb388bd2fecfc6dc7b89.camel@synopsys.com>
On Mon, Jul 09, 2018 at 02:33:26PM +0000, Alexey Brodkin wrote:
> > In fact, since alloc_dr() uses kmalloc() to allocate the entire thing,
> > it is impossible to guarantee a larger alignment than kmalloc does.
>
> Well but 4-bytes [which is critical for atomic64_t] should be much less
> than a sane cache line length so above should work.
AFAICT ARCH_KMALLOC_MINALIGN ends up being 4 on x86_32 (it doesn't
define ARCH_DMA_MINALIGN and doesn't seem to otherwise override the
thing).
So unconditionally setting the alignment of devres::data to 8 seems
broken.
WARNING: multiple messages have this Message-ID (diff)
From: peterz@infradead.org (Peter Zijlstra)
To: linux-snps-arc@lists.infradead.org
Subject: [PATCH v3] devres: Explicitly align datai[] to 64-bit
Date: Mon, 9 Jul 2018 16:49:25 +0200 [thread overview]
Message-ID: <20180709144925.GU2476@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <44727d3cebda7bee5b68fb388bd2fecfc6dc7b89.camel@synopsys.com>
On Mon, Jul 09, 2018@02:33:26PM +0000, Alexey Brodkin wrote:
> > In fact, since alloc_dr() uses kmalloc() to allocate the entire thing,
> > it is impossible to guarantee a larger alignment than kmalloc does.
>
> Well but 4-bytes [which is critical for atomic64_t] should be much less
> than a sane cache line length so above should work.
AFAICT ARCH_KMALLOC_MINALIGN ends up being 4 on x86_32 (it doesn't
define ARCH_DMA_MINALIGN and doesn't seem to otherwise override the
thing).
So unconditionally setting the alignment of devres::data to 8 seems
broken.
next prev parent reply other threads:[~2018-07-09 14:49 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-09 13:45 [PATCH v3] devres: Explicitly align datai[] to 64-bit Alexey Brodkin
2018-07-09 13:45 ` Alexey Brodkin
2018-07-09 13:54 ` Peter Zijlstra
2018-07-09 13:54 ` Peter Zijlstra
2018-07-09 13:54 ` Peter Zijlstra
2018-07-09 13:54 ` Peter Zijlstra
2018-07-09 13:54 ` Peter Zijlstra
2018-07-09 14:04 ` Mark Rutland
2018-07-09 14:04 ` Mark Rutland
2018-07-09 14:10 ` Geert Uytterhoeven
2018-07-09 14:10 ` Geert Uytterhoeven
2018-07-09 14:07 ` Alexey Brodkin
2018-07-09 14:07 ` Alexey Brodkin
2018-07-09 14:07 ` Peter Zijlstra
2018-07-09 14:07 ` Peter Zijlstra
2018-07-09 14:07 ` Peter Zijlstra
2018-07-09 14:10 ` Peter Zijlstra
2018-07-09 14:10 ` Peter Zijlstra
2018-07-09 14:10 ` Peter Zijlstra
2018-07-09 14:33 ` Alexey Brodkin
2018-07-09 14:33 ` Alexey Brodkin
2018-07-09 14:49 ` Peter Zijlstra [this message]
2018-07-09 14:49 ` Peter Zijlstra
2018-07-09 14:53 ` Alexey Brodkin
2018-07-09 14:53 ` Alexey Brodkin
2018-10-04 16:19 ` Alexey Brodkin
2018-10-04 16:19 ` Alexey Brodkin
2018-07-09 15:02 ` David Laight
2018-07-09 15:02 ` David Laight
2018-07-09 15:14 ` Peter Zijlstra
2018-07-09 15:14 ` Peter Zijlstra
2018-07-09 15:14 ` Peter Zijlstra
2018-07-09 15:29 ` Mark Rutland
2018-07-09 15:29 ` Mark Rutland
2018-07-09 15:34 ` Peter Zijlstra
2018-07-09 15:34 ` Peter Zijlstra
2018-07-09 15:34 ` Peter Zijlstra
2018-07-09 15:45 ` Peter Zijlstra
2018-07-09 15:45 ` Peter Zijlstra
2018-07-09 15:45 ` Peter Zijlstra
2018-07-09 15:48 ` Mark Rutland
2018-07-09 15:48 ` Mark Rutland
2018-07-09 16:10 ` David Laight
2018-07-09 16:10 ` David Laight
2018-07-09 20:28 ` Vineet Gupta
2018-07-09 20:28 ` Vineet Gupta
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