From: Huang Shijie <shijie8@gmail.com>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Minchan Kim <minchan.kim@gmail.com>,
akpm@linux-foundation.org, mel@csn.ul.ie, linux-mm@kvack.org
Subject: Re: [PATCH] page allocator: fix update NR_FREE_PAGES only as necessary
Date: Mon, 04 Jan 2010 17:35:15 +0800 [thread overview]
Message-ID: <4B41B653.2060204@gmail.com> (raw)
In-Reply-To: <20100104151444.96A8.A69D9226@jp.fujitsu.com>
>
>> struct per_cpu_pageset {
>> .................................................
>> #ifdef CONFIG_SMP
>> s8 stat_threshold;
>> s8 vm_stat_diff[NR_VM_ZONE_STAT_ITEMS];
>> #endif
>> } ____cacheline_aligned_in_smp;
>>
>> The field 'stat_threshold' is in the CONFIG_SMP macro, does it not need
>> the spinlock? I will read the code more carefully.
>> I saw the macro, so I thought it need the spinlock. :)
>>
> Generally, per-cpu data isn't accessed from another cpu. it only need to care
> process-context vs irq-context race.
>
>
>
If the __mod_zone_page_state() can be used without caring about the
spinlock, I think there
are several places we can move __mod_zone_page_state() out the guard
area of spinlock to
release the pressure of the zone->lock,such as in rmqueue_bulk().
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next prev parent reply other threads:[~2010-01-04 9:35 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-04 2:22 [PATCH] mm : add check for the return value Huang Shijie
2010-01-04 3:21 ` Minchan Kim
2010-01-04 4:10 ` shijie8
2010-01-04 4:48 ` Minchan Kim
2010-01-04 5:18 ` Huang Shijie
2010-01-04 6:06 ` Minchan Kim
2010-01-08 22:59 ` Andrew Morton
2010-01-04 5:52 ` [PATCH] page allocator: fix update NR_FREE_PAGES only as necessary KOSAKI Motohiro
2010-01-04 6:03 ` Minchan Kim
2010-01-04 6:11 ` Huang Shijie
2010-01-04 6:16 ` KOSAKI Motohiro
2010-01-04 9:35 ` Huang Shijie [this message]
2010-01-05 7:24 ` KOSAKI Motohiro
2010-01-04 9:58 ` Mel Gorman
2010-01-04 17:46 ` Christoph Lameter
2010-01-05 1:08 ` KOSAKI Motohiro
2010-01-08 23:02 ` Andrew Morton
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