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From: Michal Hocko <mhocko@kernel.org>
To: akpm@linux-foundation.org
Cc: ebru.akagunduz@gmail.com, aarcange@redhat.com,
	aneesh.kumar@linux.vnet.ibm.com, boaz@plexistor.com,
	gorcunov@openvz.org, hannes@cmpxchg.org, hughd@google.com,
	iamjoonsoo.kim@lge.com, kirill.shutemov@linux.intel.com,
	mgorman@suse.de, n-horiguchi@ah.jp.nec.com, riel@redhat.com,
	rientjes@google.com, vbabka@suse.cz, mm-commits@vger.kernel.org,
	linux-mm@kvack.org
Subject: Re: + mm-thp-avoid-unnecessary-swapin-in-khugepaged.patch added to -mm tree
Date: Thu, 28 Apr 2016 17:19:21 +0200	[thread overview]
Message-ID: <20160428151921.GL31489@dhcp22.suse.cz> (raw)
In-Reply-To: <57212c60.fUSE244UFwhXE+az%akpm@linux-foundation.org>

On Wed 27-04-16 14:17:20, Andrew Morton wrote:
[...]
> @@ -2484,7 +2485,14 @@ static void collapse_huge_page(struct mm
>  		goto out;
>  	}
>  
> -	__collapse_huge_page_swapin(mm, vma, address, pmd);
> +	swap = get_mm_counter(mm, MM_SWAPENTS);
> +	curr_allocstall = sum_vm_event(ALLOCSTALL);
> +	/*
> +	 * When system under pressure, don't swapin readahead.
> +	 * So that avoid unnecessary resource consuming.
> +	 */
> +	if (allocstall == curr_allocstall && swap != 0)
> +		__collapse_huge_page_swapin(mm, vma, address, pmd);
>  
>  	anon_vma_lock_write(vma->anon_vma);
>  

I have mentioned that before already but this seems like a rather weak
heuristic. Don't we really rather teach __collapse_huge_page_swapin
(resp. do_swap_page) do to an optimistic GFP_NOWAIT allocations and
back off under the memory pressure?
-- 
Michal Hocko
SUSE Labs

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       reply	other threads:[~2016-04-28 15:19 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <57212c60.fUSE244UFwhXE+az%akpm@linux-foundation.org>
2016-04-28 15:19 ` Michal Hocko [this message]
2016-05-17  7:58   ` + mm-thp-avoid-unnecessary-swapin-in-khugepaged.patch added to -mm tree Michal Hocko
2016-05-17  9:02     ` Michal Hocko
2016-05-17 11:31       ` Kirill A. Shutemov
2016-05-17 12:25         ` Michal Hocko
2016-05-19  5:00       ` Minchan Kim
2016-05-19  7:03         ` Michal Hocko
2016-05-19  7:27           ` Minchan Kim
2016-05-19  7:39             ` Michal Hocko
2016-05-20  0:21               ` Minchan Kim
2016-05-20  6:39                 ` Michal Hocko
2016-05-20  7:26                   ` Minchan Kim
2016-05-20  7:34                     ` Michal Hocko
2016-05-20  7:44                       ` Minchan Kim
2016-05-20  8:02                         ` Michal Hocko
2016-05-20  8:26                           ` Minchan Kim

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