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From: Dennis Zhou <dennis@kernel.org>
To: Dennis Zhou <dennis@kernel.org>, Tejun Heo <tj@kernel.org>,
	Christoph Lameter <cl@linux.com>
Cc: Vlad Buslov <vladbu@mellanox.com>,
	kernel-team@fb.com, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH 04/12] percpu: manage chunks based on contig_bits instead of free_bytes
Date: Wed, 27 Feb 2019 21:18:31 -0500	[thread overview]
Message-ID: <20190228021839.55779-5-dennis@kernel.org> (raw)
In-Reply-To: <20190228021839.55779-1-dennis@kernel.org>

When a chunk becomes fragmented, it can end up having a large number of
small allocation areas free. The free_bytes sorting of chunks leads to
unnecessary checking of chunks that cannot satisfy the allocation.
Switch to contig_bits sorting to prevent scanning chunks that may not be
able to service the allocation request.

Signed-off-by: Dennis Zhou <dennis@kernel.org>
---
 mm/percpu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/percpu.c b/mm/percpu.c
index b40112b2fc59..c996bcffbb2a 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -234,7 +234,7 @@ static int pcpu_chunk_slot(const struct pcpu_chunk *chunk)
 	if (chunk->free_bytes < PCPU_MIN_ALLOC_SIZE || chunk->contig_bits == 0)
 		return 0;
 
-	return pcpu_size_to_slot(chunk->free_bytes);
+	return pcpu_size_to_slot(chunk->contig_bits * PCPU_MIN_ALLOC_SIZE);
 }
 
 /* set the pointer to a chunk in a page struct */
-- 
2.17.1


  parent reply	other threads:[~2019-02-28  2:18 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-28  2:18 [PATCH 00/12] introduce percpu block scan_hint Dennis Zhou
2019-02-28  2:18 ` [PATCH 01/12] percpu: update free path with correct new free region Dennis Zhou
2019-03-02 12:56   ` Peng Fan
2019-02-28  2:18 ` [PATCH 02/12] percpu: do not search past bitmap when allocating an area Dennis Zhou
2019-03-02 13:32   ` Peng Fan
2019-03-02 22:23     ` Dennis Zhou
2019-03-03  8:41       ` Peng Fan
2019-02-28  2:18 ` [PATCH 03/12] percpu: introduce helper to determine if two regions overlap Dennis Zhou
2019-03-02 13:37   ` Peng Fan
2019-03-02 22:24     ` Dennis Zhou
2019-02-28  2:18 ` Dennis Zhou [this message]
2019-03-02 13:48   ` [PATCH 04/12] percpu: manage chunks based on contig_bits instead of free_bytes Peng Fan
2019-03-02 22:32     ` Dennis Zhou
2019-03-03  8:42       ` Peng Fan
2019-02-28  2:18 ` [PATCH 05/12] percpu: relegate chunks unusable when failing small allocations Dennis Zhou
2019-03-02 13:55   ` Peng Fan
2019-03-02 22:34     ` Dennis Zhou
2019-02-28  2:18 ` [PATCH 06/12] percpu: set PCPU_BITMAP_BLOCK_SIZE to PAGE_SIZE Dennis Zhou
2019-03-03  4:56   ` Peng Fan
2019-02-28  2:18 ` [PATCH 07/12] percpu: add block level scan_hint Dennis Zhou
2019-03-03  6:01   ` Peng Fan
2019-03-03 20:23     ` Dennis Zhou
2019-03-04  9:36       ` Peng Fan
2019-02-28  2:18 ` [PATCH 08/12] percpu: remember largest area skipped during allocation Dennis Zhou
2019-02-28  2:18 ` [PATCH 09/12] percpu: use block scan_hint to only scan forward Dennis Zhou
2019-02-28  2:18 ` [PATCH 10/12] percpu: make pcpu_block_md generic Dennis Zhou
2019-03-03  6:35   ` Peng Fan
2019-02-28  2:18 ` [PATCH 11/12] percpu: convert chunk hints to be based on pcpu_block_md Dennis Zhou
2019-03-03  8:18   ` Peng Fan
2019-03-03 20:22     ` Dennis Zhou
2019-03-04  6:36       ` Peng Fan
2019-02-28  2:18 ` [PATCH 12/12] percpu: use chunk scan_hint to skip some scanning Dennis Zhou
2019-03-03  8:38   ` Peng Fan
2019-02-28 14:47 ` [PATCH 00/12] introduce percpu block scan_hint Vlad Buslov
2019-03-13 20:19 ` Dennis Zhou

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