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From: Hillf Danton <hdanton@sina.com>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Mike Kravetz <mike.kravetz@oracle.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Michal Hocko <mhocko@suse.com>
Subject: Re: [PATCH RESEND 0/8] hugetlb: add demote/split page functionality
Date: Tue,  7 Sep 2021 16:50:01 +0800	[thread overview]
Message-ID: <20210907085001.3773-1-hdanton@sina.com> (raw)
In-Reply-To: <597a7731-3692-01b9-9e71-ba265246cc1a@suse.cz>

On Mon, 6 Sep 2021 16:40:28 +0200 Vlastimil Babka wrote:
>On 9/2/21 20:17, Mike Kravetz wrote:
>> 
>> Here is some very high level information from a long stall that was
>> interrupted.  This was an order 9 allocation from alloc_buddy_huge_page().
>> 
>> 55269.530564] __alloc_pages_slowpath: jiffies 47329325 tries 609673 cpu_tries 1   node 0 FAIL
>> [55269.539893]     r_tries 25       c_tries 609647   reclaim 47325161 compact 607     
>> 
>> Yes, in __alloc_pages_slowpath for 47329325 jiffies before being interrupted.
>> should_reclaim_retry returned true 25 times and should_compact_retry returned
>> true 609647 times.
>> Almost all time (47325161 jiffies) spent in __alloc_pages_direct_reclaim, and
>> 607 jiffies spent in __alloc_pages_direct_compact.
>> 
>> Looks like both
>> reclaim retries > MAX_RECLAIM_RETRIES
>> and
>> compaction retries > MAX_COMPACT_RETRIES
>> 
>Yeah AFAICS that's only possible with the scenario I suspected. I guess
>we should put a limit on compact retries (maybe some multiple of
>MAX_COMPACT_RETRIES) even if it thinks that reclaim could help, while
>clearly it doesn't (i.e. because somebody else is stealing the page like
>in your test case).

And/or clamp reclaim retries for costly orders

	reclaim retries = MAX_RECLAIM_RETRIES - order;

to pull down the chance for stall as low as possible.


  reply	other threads:[~2021-09-07  8:50 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-16 22:49 [PATCH RESEND 0/8] hugetlb: add demote/split page functionality Mike Kravetz
2021-08-16 22:49 ` [PATCH 1/8] hugetlb: add demote hugetlb page sysfs interfaces Mike Kravetz
2021-08-16 22:49 ` [PATCH 2/8] hugetlb: add HPageCma flag and code to free non-gigantic pages in CMA Mike Kravetz
2021-08-16 22:49 ` [PATCH 3/8] hugetlb: add demote bool to gigantic page routines Mike Kravetz
2021-08-16 22:49 ` [PATCH 4/8] hugetlb: add hugetlb demote page support Mike Kravetz
2021-08-16 22:49 ` [PATCH 5/8] hugetlb: document the demote sysfs interfaces Mike Kravetz
2021-08-16 23:28   ` Andrew Morton
2021-08-17  1:04     ` Mike Kravetz
2021-09-21 13:52   ` Aneesh Kumar K.V
2021-09-21 17:17     ` Mike Kravetz
2021-08-16 22:49 ` [PATCH 6/8] hugetlb: vmemmap optimizations when demoting hugetlb pages Mike Kravetz
2021-08-16 22:49 ` [PATCH 7/8] hugetlb: prepare destroy and prep routines for vmemmap optimized pages Mike Kravetz
2021-08-16 22:49 ` [PATCH 8/8] hugetlb: Optimized demote vmemmap optimizatized pages Mike Kravetz
2021-08-16 23:23 ` [PATCH RESEND 0/8] hugetlb: add demote/split page functionality Andrew Morton
2021-08-17  0:17   ` Mike Kravetz
2021-08-17  0:39     ` Andrew Morton
2021-08-17  0:58       ` Mike Kravetz
2021-08-16 23:27 ` Andrew Morton
2021-08-17  0:46   ` Mike Kravetz
2021-08-17  1:46     ` Andrew Morton
2021-08-17  7:30       ` David Hildenbrand
2021-08-17 16:19         ` Mike Kravetz
2021-08-17 18:49           ` David Hildenbrand
2021-08-24 22:08       ` Mike Kravetz
2021-08-26  7:32         ` Hillf Danton
2021-08-27 17:22         ` Vlastimil Babka
2021-08-27 23:04           ` Mike Kravetz
2021-08-30 10:11             ` Vlastimil Babka
2021-09-02 18:17               ` Mike Kravetz
2021-09-06 14:40                 ` Vlastimil Babka
2021-09-07  8:50                   ` Hillf Danton [this message]
2021-09-08 21:00                     ` Mike Kravetz
2021-09-09  4:07                       ` Hillf Danton
2021-09-09 11:54                       ` Michal Hocko
2021-09-09 13:45                         ` Vlastimil Babka
2021-09-09 21:31                           ` Mike Kravetz
2021-09-10  8:20                           ` Michal Hocko
2021-09-11  0:11                             ` Mike Kravetz
2021-09-11  3:11                               ` Hillf Danton
2021-09-13 15:50                               ` Michal Hocko
2021-09-15 16:57                                 ` Mike Kravetz
2021-09-17 20:44                                   ` Mike Kravetz

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