From: Eric Dumazet <eric.dumazet@gmail.com>
To: Shaohua Li <shaohua.li@intel.com>
Cc: "hpa@zytor.com" <hpa@zytor.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"mingo@redhat.com" <mingo@redhat.com>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"hpa@linux.intel.com" <hpa@linux.intel.com>
Subject: Re: [tip:x86/mm] percpu: Introduce a read-mostly percpu API
Date: Thu, 21 Oct 2010 07:33:50 +0200 [thread overview]
Message-ID: <1287639230.2545.117.camel@edumazet-laptop> (raw)
In-Reply-To: <20101021013833.GA21863@sli10-conroe.sh.intel.com>
Le jeudi 21 octobre 2010 à 09:38 +0800, Shaohua Li a écrit :
> Hi hpa,
> On Thu, Oct 21, 2010 at 07:06:59AM +0800, tip-bot for Shaohua Li wrote:
> > [ hpa: moved it *after* the page-aligned section, for obvious
> > reasons. ]
> move it after page-aligned section can't guarantee to avoid cache false sharing.
> we need:
> . = ALIGN(CACHE_LINE_SIZE);
> *(.data..percpu..readmostly)
> . = ALIGN(CACHE_LINE_SIZE);
> To make sure before/after readmostly section doesn't share cache line with
> others. The headcache is some arch need L1_CACHE_SIZE and others need
> (1 << INTERNODE_CACHE_SHIFT). We need change all ARCHs to make this happen.
Really, readmostly percpu variables dont need INTERNODE_CACHE_SHIFT, as
this is read mostly, and per cpu vars ;)
Just use L1_CACHE_BYTES
*(.data..percpu..first) \
*(.data..percpu..page_aligned) \
+ . = ALIGN(L1_CACHE_BYTES \
+ *(.data..percpu..readmostly) \
+ . = ALIGN(L1_CACHE_BYTES \
*(.data..percpu) \
next prev parent reply other threads:[~2010-10-21 5:34 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-20 3:07 [PATCH 1/2]percpu: introduce read mostly " Shaohua Li
2010-10-20 5:18 ` Eric Dumazet
2010-10-20 6:00 ` H. Peter Anvin
2010-10-20 7:35 ` Andi Kleen
2010-10-20 7:53 ` Eric Dumazet
2010-10-20 21:38 ` H. Peter Anvin
2010-10-20 21:42 ` H. Peter Anvin
2010-10-20 21:33 ` H. Peter Anvin
2010-10-20 23:06 ` [tip:x86/mm] percpu: Introduce a read-mostly " tip-bot for Shaohua Li
2010-10-21 1:38 ` Shaohua Li
2010-10-21 2:53 ` H. Peter Anvin
2010-10-21 5:33 ` Eric Dumazet [this message]
2010-10-21 5:54 ` H. Peter Anvin
2010-10-21 6:07 ` Eric Dumazet
2010-10-21 6:09 ` H. Peter Anvin
2010-10-21 6:17 ` Shaohua Li
2010-10-21 6:48 ` Eric Dumazet
2010-10-21 6:54 ` H. Peter Anvin
2010-10-21 6:10 ` H. Peter Anvin
2010-10-21 7:40 ` [tip:x86/mm] x86-32, percpu: Correct the ordering of the percpu readmostly section tip-bot for H. Peter Anvin
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