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From: Michal Hocko <mhocko@suse.com>
To: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>, Hillf Danton <hdanton@sina.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH RESEND 0/8] hugetlb: add demote/split page functionality
Date: Mon, 13 Sep 2021 17:50:41 +0200	[thread overview]
Message-ID: <YT9zUaPofENSMQHg@dhcp22.suse.cz> (raw)
In-Reply-To: <2519e0f8-98ee-6bad-3895-ac733635e5b0@oracle.com>

On Fri 10-09-21 17:11:05, Mike Kravetz wrote:
[...]
> @@ -5064,8 +5068,18 @@ bool gfp_pfmemalloc_allowed(gfp_t gfp_mask)
>  	if (did_some_progress > 0 &&
>  			should_compact_retry(ac, order, alloc_flags,
>  				compact_result, &compact_priority,
> -				&compaction_retries))
> +				&compaction_retries)) {
> +		/*
> +		 * In one pathological case, pages can be stolen immediately
> +		 * after reclaimed.  It looks like we are making progress, and
> +		 * compaction_retries is not incremented.  This could cause
> +		 * an indefinite number of retries.  Cap the number of retries
> +		 * for costly orders.
> +		 */
> +		if (max_tries && tries > max_tries)
> +			goto nopage;
>  		goto retry;
> +	}

I do not think this is a good approach. We do not want to play with
retries numbers. If we want to go with a minimal change for now then the
compaction feedback mechanism should track the number of reclaimed pages
to satisfy watermarks and if that grows beyond reasonable (proportionaly
to the request size) then simply give up rather than keep trying again
and again.

-- 
Michal Hocko
SUSE Labs

  reply	other threads:[~2021-09-13 15:51 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-16 22:49 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
2021-08-27 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
     [not found]                 ` <20210907085001.3773-1-hdanton@sina.com>
2021-09-08 21:00                   ` Mike Kravetz
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
2021-09-13 15:50                             ` Michal Hocko [this message]
2021-09-15 16:57                               ` Mike Kravetz
2021-09-17 20:44                                 ` Mike Kravetz

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