linux-kernel - Re: [PATCH vmalloc] reduce purge

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Date:   Tue, 18 Oct 2016 10:55:26 +0800
From:   zhouxianrong <zhouxianrong@...wei.com>
To:     Christoph Hellwig <hch@...radead.org>
CC:     <linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>,
        <akpm@...ux-foundation.org>, <rientjes@...gle.com>,
        <hannes@...xchg.org>, <chris@...is-wilson.co.uk>,
        <vdavydov.dev@...il.com>, <mgorman@...hsingularity.net>,
        <joe@...ches.com>, <shawn.lin@...k-chips.com>,
        <iamjoonsoo.kim@....com>, <kuleshovmail@...il.com>,
        <zhouxiyu@...wei.com>, <zhangshiming5@...wei.com>,
        <won.ho.park@...wei.com>, <tuxiaobing@...wei.com>
Subject: Re: [PATCH vmalloc] reduce purge_lock range and hold time of

hey Hellwig:
	cond_resched_lock is a good choice. i mixed the cond_resched_lock and batch to balance of
realtime and performance and resubmit this patch.

On 2016/10/16 0:55, Christoph Hellwig wrote:
> On Sat, Oct 15, 2016 at 10:12:48PM +0800, zhouxianrong@...wei.com wrote:
>> From: z00281421 <z00281421@...esmail.huawei.com>
>>
>> i think no need to place __free_vmap_area loop in purge_lock;
>> _free_vmap_area could be non-atomic operations with flushing tlb
>> but must be done after flush tlb. and the whole__free_vmap_area loops
>> also could be non-atomic operations. if so we could improve realtime
>> because the loop times sometimes is larg and spend a few time.
>
> Right, see the previous patch in reply to Joel that drops purge_lock
> entirely.
>
> Instead of your open coded batch counter you probably want to add
> a cond_resched_lock after the call to __free_vmap_area.
>
> .
>