Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757142AbdGXXFA (ORCPT ); Mon, 24 Jul 2017 19:05:00 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:34168 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756972AbdGXXDB (ORCPT ); Mon, 24 Jul 2017 19:03:01 -0400 From: Dennis Zhou To: Tejun Heo , Christoph Lameter , Josef Bacik CC: , , , Dennis Zhou Subject: [PATCH v2 18/23] percpu: keep track of the best offset for contig hints Date: Mon, 24 Jul 2017 19:02:15 -0400 Message-ID: <20170724230220.21774-19-dennisz@fb.com> X-Mailer: git-send-email 2.13.3 In-Reply-To: <20170724230220.21774-1-dennisz@fb.com> References: <20170724230220.21774-1-dennisz@fb.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [192.168.52.123] X-Proofpoint-Spam-Reason: safe X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-07-24_14:,, signatures=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2263 Lines: 60 From: "Dennis Zhou (Facebook)" This patch makes the contig hint starting offset optimization from the previous patch as honest as it can be. For both chunk and block starting offsets, make sure it keeps the starting offset with the best alignment. The block skip optimization is added in a later patch when the pcpu_find_block_fit iterator is swapped in. Signed-off-by: Dennis Zhou --- mm/percpu.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/mm/percpu.c b/mm/percpu.c index 3732373..aaad747 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -394,12 +394,18 @@ static inline int pcpu_cnt_pop_pages(struct pcpu_chunk *chunk, int bit_off, * @bits: size of free area * * This updates the chunk's contig hint and starting offset given a free area. + * Choose the best starting offset if the contig hint is equal. */ static void pcpu_chunk_update(struct pcpu_chunk *chunk, int bit_off, int bits) { if (bits > chunk->contig_bits) { chunk->contig_bits_start = bit_off; chunk->contig_bits = bits; + } else if (bits == chunk->contig_bits && chunk->contig_bits_start && + (!bit_off || + __ffs(bit_off) > __ffs(chunk->contig_bits_start))) { + /* use the start with the best alignment */ + chunk->contig_bits_start = bit_off; } } @@ -454,7 +460,8 @@ static void pcpu_chunk_refresh_hint(struct pcpu_chunk *chunk) * @end: end offset in block * * Updates a block given a known free area. The region [start, end) is - * expected to be the entirety of the free area within a block. + * expected to be the entirety of the free area within a block. Chooses + * the best starting offset if the contig hints are equal. */ static void pcpu_block_update(struct pcpu_block_md *block, int start, int end) { @@ -470,6 +477,10 @@ static void pcpu_block_update(struct pcpu_block_md *block, int start, int end) if (contig > block->contig_hint) { block->contig_hint_start = start; block->contig_hint = contig; + } else if (block->contig_hint_start && contig == block->contig_hint && + (!start || __ffs(start) > __ffs(block->contig_hint_start))) { + /* use the start with the best alignment */ + block->contig_hint_start = start; } } -- 2.9.3