Re: [wrecked] mm-compaction-more-reliably-increase-direct-compaction-priority.patch removed from -mm tree

[Michal Hocko <mhocko@kernel.org>]

Hi Andrew,
I guess the reason this patch has been dropped is due to
mm-oom-prevent-pre-mature-oom-killer-invocation-for-high-order-request.patch.

I guess we will wait for the above patch to get to Linus, revert it in mmotm
and re-apply
mm-compaction-more-reliably-increase-direct-compaction-priority.patch
again, right?

On Tue 23-08-16 13:59:52, Andrew Morton wrote:
> 
> The patch titled
>      Subject: mm, compaction: more reliably increase direct compaction priority
> has been removed from the -mm tree.  Its filename was
>      mm-compaction-more-reliably-increase-direct-compaction-priority.patch
> 
> This patch was dropped because other changes were merged, which wrecked this patch
> 
> ------------------------------------------------------
> From: Vlastimil Babka <vbabka@suse.cz>
> Subject: mm, compaction: more reliably increase direct compaction priority
> 
> During reclaim/compaction loop, compaction priority can be increased by
> the should_compact_retry() function, but the current code is not optimal. 
> Priority is only increased when compaction_failed() is true, which means
> that compaction has scanned the whole zone.  This may not happen even
> after multiple attempts with a lower priority due to parallel activity, so
> we might needlessly struggle on the lower priorities and possibly run out
> of compaction retry attempts in the process.
> 
> After this patch we are guaranteed at least one attempt at the highest
> compaction priority even if we exhaust all retries at the lower
> priorities.
> 
> Link: http://lkml.kernel.org/r/20160810091226.6709-7-vbabka@suse.cz
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: Mel Gorman <mgorman@techsingularity.net>
> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> Cc: David Rientjes <rientjes@google.com>
> Cc: Rik van Riel <riel@redhat.com>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
> 
>  mm/page_alloc.c |   18 +++++++++++-------
>  1 file changed, 11 insertions(+), 7 deletions(-)
> 
> diff -puN mm/page_alloc.c~mm-compaction-more-reliably-increase-direct-compaction-priority mm/page_alloc.c
> --- a/mm/page_alloc.c~mm-compaction-more-reliably-increase-direct-compaction-priority
> +++ a/mm/page_alloc.c
> @@ -3153,13 +3153,8 @@ should_compact_retry(struct alloc_contex
>  	 * so it doesn't really make much sense to retry except when the
>  	 * failure could be caused by insufficient priority
>  	 */
> -	if (compaction_failed(compact_result)) {
> -		if (*compact_priority > MIN_COMPACT_PRIORITY) {
> -			(*compact_priority)--;
> -			return true;
> -		}
> -		return false;
> -	}
> +	if (compaction_failed(compact_result))
> +		goto check_priority;
>  
>  	/*
>  	 * make sure the compaction wasn't deferred or didn't bail out early
> @@ -3183,6 +3178,15 @@ should_compact_retry(struct alloc_contex
>  	if (compaction_retries <= max_retries)
>  		return true;
>  
> +	/*
> +	 * Make sure there is at least one attempt at the highest priority
> +	 * if we exhausted all retries at the lower priorities
> +	 */
> +check_priority:
> +	if (*compact_priority > MIN_COMPACT_PRIORITY) {
> +		(*compact_priority)--;
> +		return true;
> +	}
>  	return false;
>  }
>  #else
> _
> 
> Patches currently in -mm which might be from vbabka@suse.cz are
> 
> mm-compaction-make-whole_zone-flag-ignore-cached-scanner-positions.patch
> mm-compaction-cleanup-unused-functions.patch
> mm-compaction-rename-compact_partial-to-compact_success.patch
> mm-compaction-dont-recheck-watermarks-after-compact_success.patch
> mm-compaction-add-the-ultimate-direct-compaction-priority.patch
> mm-compaction-add-the-ultimate-direct-compaction-priority-fix.patch
> mm-compaction-use-correct-watermark-when-checking-compaction-success.patch
> mm-compaction-create-compact_gap-wrapper.patch
> mm-compaction-create-compact_gap-wrapper-fix.patch
> mm-compaction-use-proper-alloc_flags-in-__compaction_suitable.patch
> mm-compaction-require-only-min-watermarks-for-non-costly-orders.patch
> mm-compaction-require-only-min-watermarks-for-non-costly-orders-fix.patch
> mm-vmscan-make-compaction_ready-more-accurate-and-readable.patch

-- 
Michal Hocko
SUSE Labs

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