From: Wei Yang <richardw.yang@linux.intel.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Wei Yang <richardw.yang@linux.intel.com>,
Mel Gorman <mgorman@techsingularity.net>,
akpm@linux-foundation.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, shakeelb@google.com,
yang.shi@linux.alibaba.com
Subject: Re: [RFC Patch] mm/vmscan.c: not inherit classzone_idx from previous reclaim
Date: Fri, 14 Feb 2020 15:35:59 +0800 [thread overview]
Message-ID: <20200214073559.GA28295@richard> (raw)
In-Reply-To: <20200214024806.GU7778@bombadil.infradead.org>
On Thu, Feb 13, 2020 at 06:48:06PM -0800, Matthew Wilcox wrote:
>On Fri, Feb 14, 2020 at 10:05:15AM +0800, Wei Yang wrote:
>> On Wed, Feb 12, 2020 at 07:43:33AM +0000, Mel Gorman wrote:
>> >Broadly speaking it was driven by cases whereby kswapd either a) fell
>> >asleep prematurely and there were many stalls in direct reclaim before
>> >kswapd recovered, b) stalls in direct reclaim immediately after kswapd went
>> >to sleep or c) kswapd reclaimed for lower zones and went to sleep while
>> >parallel tasks were direct reclaiming in higher zones or higher orders.
>>
>> Thanks for your explanation. I am trying to understand the connection between
>> those cases and the behavior of kswapd.
>>
>> In summary, all three cases are related to direct reclaim, while happens in
>> three different timing of kswapd:
>
>Reclaim performed by kswapd is the opposite of direct reclaim. Direct
>reclaim is reclaim initiated by a task which is trying to allocate memory.
>If a task cannot perform direct reclaim itself, it may ask kswapd to
>attempt to reclaim memory for it.
Not totally opposite, I think.
They both reclaim some memory, while after direct reclaim, some freed memory
will be allocated.
Is this the difference you want to mention?
--
Wei Yang
Help you, Help me
prev parent reply other threads:[~2020-02-14 7:35 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-09 7:41 [RFC Patch] mm/vmscan.c: not inherit classzone_idx from previous reclaim Wei Yang
2020-02-11 10:42 ` Mel Gorman
2020-02-12 2:25 ` Wei Yang
2020-02-12 7:43 ` Mel Gorman
2020-02-14 2:05 ` Wei Yang
2020-02-14 2:48 ` Matthew Wilcox
2020-02-14 7:35 ` Wei Yang [this message]
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