Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933028AbdGXXFr (ORCPT ); Mon, 24 Jul 2017 19:05:47 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:44248 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933000AbdGXXC6 (ORCPT ); Mon, 24 Jul 2017 19:02:58 -0400 From: Dennis Zhou To: Tejun Heo , Christoph Lameter , Josef Bacik CC: , , , Dennis Zhou Subject: [PATCH v2 16/23] percpu: add first_bit to keep track of the first free in the bitmap Date: Mon, 24 Jul 2017 19:02:13 -0400 Message-ID: <20170724230220.21774-17-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: 3295 Lines: 95 From: "Dennis Zhou (Facebook)" This patch adds first_bit to keep track of the first free bit in the bitmap. This hint helps prevent scanning of fully allocated blocks. Signed-off-by: Dennis Zhou --- mm/percpu-internal.h | 2 +- mm/percpu-stats.c | 1 + mm/percpu.c | 17 +++++++++++++++-- 3 files changed, 17 insertions(+), 3 deletions(-) diff --git a/mm/percpu-internal.h b/mm/percpu-internal.h index 252ae9e..e60e049 100644 --- a/mm/percpu-internal.h +++ b/mm/percpu-internal.h @@ -36,7 +36,7 @@ struct pcpu_chunk { struct pcpu_block_md *md_blocks; /* metadata blocks */ void *data; /* chunk data */ - int first_free; /* no free below this */ + int first_bit; /* no free below this */ bool immutable; /* no [de]population allowed */ int start_offset; /* the overlap with the previous region to have a page aligned diff --git a/mm/percpu-stats.c b/mm/percpu-stats.c index ad03d73..6142484 100644 --- a/mm/percpu-stats.c +++ b/mm/percpu-stats.c @@ -121,6 +121,7 @@ static void chunk_map_stats(struct seq_file *m, struct pcpu_chunk *chunk, P("nr_alloc", chunk->nr_alloc); P("max_alloc_size", chunk->max_alloc_size); P("empty_pop_pages", chunk->nr_empty_pop_pages); + P("first_bit", chunk->first_bit); P("free_bytes", chunk->free_bytes); P("contig_bytes", chunk->contig_bits * PCPU_MIN_ALLOC_SIZE); P("sum_frag", sum_frag); diff --git a/mm/percpu.c b/mm/percpu.c index 6bddc02..ad70c67 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -420,7 +420,7 @@ static void pcpu_chunk_refresh_hint(struct pcpu_chunk *chunk) chunk->contig_bits = 0; bits = nr_empty_pop_pages = 0; - pcpu_for_each_unpop_region(chunk->alloc_map, rs, re, 0, + pcpu_for_each_unpop_region(chunk->alloc_map, rs, re, chunk->first_bit, pcpu_chunk_map_bits(chunk)) { bits = re - rs; @@ -639,7 +639,8 @@ static int pcpu_find_block_fit(struct pcpu_chunk *chunk, int alloc_bits, int bit_off, bits; int re; /* region end */ - pcpu_for_each_unpop_region(chunk->alloc_map, bit_off, re, 0, + pcpu_for_each_unpop_region(chunk->alloc_map, bit_off, re, + chunk->first_bit, pcpu_chunk_map_bits(chunk)) { bits = re - bit_off; @@ -708,6 +709,13 @@ static int pcpu_alloc_area(struct pcpu_chunk *chunk, int alloc_bits, chunk->free_bytes -= alloc_bits * PCPU_MIN_ALLOC_SIZE; + /* update first free bit */ + if (bit_off == chunk->first_bit) + chunk->first_bit = find_next_zero_bit( + chunk->alloc_map, + pcpu_chunk_map_bits(chunk), + bit_off + alloc_bits); + pcpu_block_update_hint_alloc(chunk, bit_off, alloc_bits); pcpu_chunk_relocate(chunk, oslot); @@ -743,6 +751,9 @@ static void pcpu_free_area(struct pcpu_chunk *chunk, int off) /* update metadata */ chunk->free_bytes += bits * PCPU_MIN_ALLOC_SIZE; + /* update first free bit */ + chunk->first_bit = min(chunk->first_bit, bit_off); + pcpu_block_update_hint_free(chunk, bit_off, bits); pcpu_chunk_relocate(chunk, oslot); @@ -834,6 +845,8 @@ static struct pcpu_chunk * __init pcpu_alloc_first_chunk(unsigned long tmp_addr, set_bit(0, chunk->bound_map); set_bit(offset_bits, chunk->bound_map); + chunk->first_bit = offset_bits; + pcpu_block_update_hint_alloc(chunk, 0, offset_bits); } -- 2.9.3