From: Vlastimil Babka <vbabka@suse.cz>
To: Mel Gorman <mgorman@techsingularity.net>,
Andrew Morton <akpm@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Zi Yan <zi.yan@cs.rutgers.edu>, Michal Hocko <mhocko@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>
Subject: Re: [PATCH 3/5] mm: Use alloc_flags to record if kswapd can wake
Date: Mon, 26 Nov 2018 14:38:07 +0100 [thread overview]
Message-ID: <39711f99-1a2a-67d3-5cb0-a63ac739a917@suse.cz> (raw)
In-Reply-To: <20181123114528.28802-4-mgorman@techsingularity.net>
On 11/23/18 12:45 PM, Mel Gorman wrote:
> This is a preparation patch that copies the GFP flag __GFP_KSWAPD_RECLAIM
> into alloc_flags. This is a preparation patch only that avoids having to
> pass gfp_mask through a long callchain in a future patch.
>
> Note that the setting in the fast path happens in alloc_flags_nofragment()
> and it may be claimed that this has nothing to do with ALLOC_NO_FRAGMENT.
> That's true in this patch but is not true later so it's done now for
> easier review to show where the flag needs to be recorded.
>
> No functional change.
>
> Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Small bug below:
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -3278,10 +3278,15 @@ static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
> * fragmentation between the Normal and DMA32 zones.
> */
> static inline unsigned int
> -alloc_flags_nofragment(struct zone *zone)
> +alloc_flags_nofragment(struct zone *zone, gfp_t gfp_mask)
> {
> + unsigned int alloc_flags = 0;
> +
> + if (gfp_mask & __GFP_KSWAPD_RECLAIM)
> + alloc_flags |= ALLOC_KSWAPD;
> +
> if (zone_idx(zone) != ZONE_NORMAL)
> - return 0;
> + goto out;
>
> /*
> * If ZONE_DMA32 exists, assume it is the one after ZONE_NORMAL and
> @@ -3290,13 +3295,14 @@ alloc_flags_nofragment(struct zone *zone)
> */
> BUILD_BUG_ON(ZONE_NORMAL - ZONE_DMA32 != 1);
> if (nr_online_nodes > 1 && !populated_zone(--zone))
> - return 0;
> + goto out;
>
> - return ALLOC_NOFRAGMENT;
> +out:
> + return alloc_flags;
> }
> #else
> static inline unsigned int
> -alloc_flags_nofragment(struct zone *zone)
> +alloc_flags_nofragment(struct zone *zone, gfp_t gfp_mask)
> {
> return 0;
The !CONFIG_ZONE_DMA32 version should still set ALLOC_KSWAPD, right?
> }
> @@ -3939,6 +3945,9 @@ gfp_to_alloc_flags(gfp_t gfp_mask)
> } else if (unlikely(rt_task(current)) && !in_interrupt())
> alloc_flags |= ALLOC_HARDER;
>
> + if (gfp_mask & __GFP_KSWAPD_RECLAIM)
> + alloc_flags |= ALLOC_KSWAPD;
> +
> #ifdef CONFIG_CMA
> if (gfpflags_to_migratetype(gfp_mask) == MIGRATE_MOVABLE)
> alloc_flags |= ALLOC_CMA;
next prev parent reply other threads:[~2018-11-26 13:38 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-23 11:45 [PATCH 0/5] Fragmentation avoidance improvements v5 Mel Gorman
2018-11-23 11:45 ` [PATCH 1/5] mm, page_alloc: Spread allocations across zones before introducing fragmentation Mel Gorman
2018-11-26 12:36 ` Vlastimil Babka
2018-11-23 11:45 ` [PATCH 2/5] mm: Move zone watermark accesses behind an accessor Mel Gorman
2018-11-23 11:45 ` [PATCH 3/5] mm: Use alloc_flags to record if kswapd can wake Mel Gorman
2018-11-26 13:38 ` Vlastimil Babka [this message]
2018-11-26 14:35 ` [PATCH] mm: Use alloc_flags to record if kswapd can wake -fix Mel Gorman
2018-11-23 11:45 ` [PATCH 4/5] mm: Reclaim small amounts of memory when an external fragmentation event occurs Mel Gorman
2018-11-27 9:23 ` Vlastimil Babka
2018-11-23 11:45 ` [PATCH 5/5] mm: Stall movable allocations until kswapd progresses during serious external fragmentation event Mel Gorman
2018-11-27 13:20 ` Vlastimil Babka
2018-11-27 17:51 ` Mel Gorman
2018-12-05 8:06 ` Mel Gorman
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