Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753988AbdGXXDm (ORCPT ); Mon, 24 Jul 2017 19:03:42 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:37823 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932908AbdGXXCx (ORCPT ); Mon, 24 Jul 2017 19:02:53 -0400 From: Dennis Zhou To: Tejun Heo , Christoph Lameter , Josef Bacik CC: , , , Dennis Zhou Subject: [PATCH v2 11/23] percpu: introduce nr_empty_pop_pages to help empty page accounting Date: Mon, 24 Jul 2017 19:02:08 -0400 Message-ID: <20170724230220.21774-12-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: 3385 Lines: 98 From: "Dennis Zhou (Facebook)" pcpu_nr_empty_pop_pages is used to ensure there are a handful of free pages around to serve atomic allocations. A new field, nr_empty_pop_pages, is added to the pcpu_chunk struct to keep track of the number of empty pages. This field is needed as the number of empty populated pages is globally tracked and deltas are used to update in the bitmap allocator. Pages that contain a hidden area are not considered to be empty. This new field is exposed in percpu_stats. Signed-off-by: Dennis Zhou --- mm/percpu-internal.h | 1 + mm/percpu-stats.c | 1 + mm/percpu.c | 11 ++++++++--- 3 files changed, 10 insertions(+), 3 deletions(-) diff --git a/mm/percpu-internal.h b/mm/percpu-internal.h index 34cb979..c4c8fc4 100644 --- a/mm/percpu-internal.h +++ b/mm/percpu-internal.h @@ -32,6 +32,7 @@ struct pcpu_chunk { int nr_pages; /* # of pages served by this chunk */ int nr_populated; /* # of populated pages */ + int nr_empty_pop_pages; /* # of empty populated pages */ unsigned long populated[]; /* populated bitmap */ }; diff --git a/mm/percpu-stats.c b/mm/percpu-stats.c index ffbdb96..e146b58 100644 --- a/mm/percpu-stats.c +++ b/mm/percpu-stats.c @@ -100,6 +100,7 @@ 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("free_size", chunk->free_size); P("contig_hint", chunk->contig_hint); P("sum_frag", sum_frag); diff --git a/mm/percpu.c b/mm/percpu.c index 773dafe..657ab08 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -757,11 +757,14 @@ static struct pcpu_chunk * __init pcpu_alloc_first_chunk(unsigned long tmp_addr, chunk->immutable = true; bitmap_fill(chunk->populated, chunk->nr_pages); chunk->nr_populated = chunk->nr_pages; + chunk->nr_empty_pop_pages = chunk->nr_pages; chunk->contig_hint = chunk->free_size = map_size; if (chunk->start_offset) { /* hide the beginning of the bitmap */ + chunk->nr_empty_pop_pages--; + chunk->map[0] = 1; chunk->map[1] = chunk->start_offset; chunk->map_used = 1; @@ -773,6 +776,8 @@ static struct pcpu_chunk * __init pcpu_alloc_first_chunk(unsigned long tmp_addr, if (chunk->end_offset) { /* hide the end of the bitmap */ + chunk->nr_empty_pop_pages--; + chunk->map[++chunk->map_used] = region_size | 1; } @@ -836,6 +841,7 @@ static void pcpu_chunk_populated(struct pcpu_chunk *chunk, bitmap_set(chunk->populated, page_start, nr); chunk->nr_populated += nr; + chunk->nr_empty_pop_pages += nr; pcpu_nr_empty_pop_pages += nr; } @@ -858,6 +864,7 @@ static void pcpu_chunk_depopulated(struct pcpu_chunk *chunk, bitmap_clear(chunk->populated, page_start, nr); chunk->nr_populated -= nr; + chunk->nr_empty_pop_pages -= nr; pcpu_nr_empty_pop_pages -= nr; } @@ -1782,9 +1789,7 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai, /* link the first chunk in */ pcpu_first_chunk = chunk; - i = (pcpu_first_chunk->start_offset) ? 1 : 0; - pcpu_nr_empty_pop_pages += - pcpu_count_occupied_pages(pcpu_first_chunk, i); + pcpu_nr_empty_pop_pages = pcpu_first_chunk->nr_empty_pop_pages; pcpu_chunk_relocate(pcpu_first_chunk, -1); pcpu_stats_chunk_alloc(); -- 2.9.3