Re: [PATCH v2 3/3] mm/compaction: speed up pageblock_pfn_to_page() when zone is contiguous
From: Andrew Morton
Date: Tue Feb 09 2016 - 15:53:08 EST
On Tue, 9 Feb 2016 18:58:32 +0100 Vlastimil Babka <vbabka@xxxxxxx> wrote:
> On 02/05/2016 05:11 PM, Joonsoo Kim wrote:
> > Yeah, it seems wrong to me. :)
> > Here goes fix.
>
> Doesn't apply for me, even after fixing the most obvious line wraps.
> Seems like the version in mmotm is still your original patch and
> Andrew's hotfix?
Yes, that patch was hopelessly mailer-mangled. I painstakingly fixed
it up and generated the incremental:
From: Joonsoo Kim <js1304@xxxxxxxxx>
Subject: mm-compaction-speed-up-pageblock_pfn_to_page-when-zone-is-contiguous-v3
v3
o remove pfn_valid_within() check for all pages in the pageblock
because pageblock_pfn_to_page() is only called with pageblock aligned pfn.
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Reported-by: Aaron Lu <aaron.lu@xxxxxxxxx>
Tested-by: Aaron Lu <aaron.lu@xxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 139 ++++++++++++++++++++++------------------------
1 file changed, 69 insertions(+), 70 deletions(-)
diff -puN mm/page_alloc.c~mm-compaction-speed-up-pageblock_pfn_to_page-when-zone-is-contiguous-v3 mm/page_alloc.c
--- a/mm/page_alloc.c~mm-compaction-speed-up-pageblock_pfn_to_page-when-zone-is-contiguous-v3
+++ a/mm/page_alloc.c
@@ -1128,6 +1128,75 @@ void __init __free_pages_bootmem(struct
return __free_pages_boot_core(page, pfn, order);
}
+/*
+ * Check that the whole (or subset of) a pageblock given by the interval of
+ * [start_pfn, end_pfn) is valid and within the same zone, before scanning it
+ * with the migration of free compaction scanner. The scanners then need to
+ * use only pfn_valid_within() check for arches that allow holes within
+ * pageblocks.
+ *
+ * Return struct page pointer of start_pfn, or NULL if checks were not passed.
+ *
+ * It's possible on some configurations to have a setup like node0 node1 node0
+ * i.e. it's possible that all pages within a zones range of pages do not
+ * belong to a single zone. We assume that a border between node0 and node1
+ * can occur within a single pageblock, but not a node0 node1 node0
+ * interleaving within a single pageblock. It is therefore sufficient to check
+ * the first and last page of a pageblock and avoid checking each individual
+ * page in a pageblock.
+ */
+struct page *__pageblock_pfn_to_page(unsigned long start_pfn,
+ unsigned long end_pfn, struct zone *zone)
+{
+ struct page *start_page;
+ struct page *end_page;
+
+ /* end_pfn is one past the range we are checking */
+ end_pfn--;
+
+ if (!pfn_valid(start_pfn) || !pfn_valid(end_pfn))
+ return NULL;
+
+ start_page = pfn_to_page(start_pfn);
+
+ if (page_zone(start_page) != zone)
+ return NULL;
+
+ end_page = pfn_to_page(end_pfn);
+
+ /* This gives a shorter code than deriving page_zone(end_page) */
+ if (page_zone_id(start_page) != page_zone_id(end_page))
+ return NULL;
+
+ return start_page;
+}
+
+void set_zone_contiguous(struct zone *zone)
+{
+ unsigned long block_start_pfn = zone->zone_start_pfn;
+ unsigned long block_end_pfn;
+
+ block_end_pfn = ALIGN(block_start_pfn + 1, pageblock_nr_pages);
+ for (; block_start_pfn < zone_end_pfn(zone);
+ block_start_pfn = block_end_pfn,
+ block_end_pfn += pageblock_nr_pages) {
+
+ block_end_pfn = min(block_end_pfn, zone_end_pfn(zone));
+
+ if (!__pageblock_pfn_to_page(block_start_pfn,
+ block_end_pfn, zone))
+ return;
+ }
+
+ /* We confirm that there is no hole */
+ zone->contiguous = true;
+}
+
+void clear_zone_contiguous(struct zone *zone)
+{
+ zone->contiguous = false;
+}
+
#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
static void __init deferred_free_range(struct page *page,
unsigned long pfn, int nr_pages)
@@ -1304,76 +1373,6 @@ void __init page_alloc_init_late(void)
set_zone_contiguous(zone);
}
-/*
- * Check that the whole (or subset of) a pageblock given by the interval of
- * [start_pfn, end_pfn) is valid and within the same zone, before scanning it
- * with the migration of free compaction scanner. The scanners then need to
- * use only pfn_valid_within() check for arches that allow holes within
- * pageblocks.
- *
- * Return struct page pointer of start_pfn, or NULL if checks were not passed.
- *
- * It's possible on some configurations to have a setup like node0 node1 node0
- * i.e. it's possible that all pages within a zones range of pages do not
- * belong to a single zone. We assume that a border between node0 and node1
- * can occur within a single pageblock, but not a node0 node1 node0
- * interleaving within a single pageblock. It is therefore sufficient to check
- * the first and last page of a pageblock and avoid checking each individual
- * page in a pageblock.
- */
-struct page *__pageblock_pfn_to_page(unsigned long start_pfn,
- unsigned long end_pfn, struct zone *zone)
-{
- struct page *start_page;
- struct page *end_page;
-
- /* end_pfn is one past the range we are checking */
- end_pfn--;
-
- if (!pfn_valid(start_pfn) || !pfn_valid(end_pfn))
- return NULL;
-
- start_page = pfn_to_page(start_pfn);
-
- if (page_zone(start_page) != zone)
- return NULL;
-
- end_page = pfn_to_page(end_pfn);
-
- /* This gives a shorter code than deriving page_zone(end_page) */
- if (page_zone_id(start_page) != page_zone_id(end_page))
- return NULL;
-
- return start_page;
-}
-
-void set_zone_contiguous(struct zone *zone)
-{
- unsigned long block_start_pfn = zone->zone_start_pfn;
- unsigned long block_end_pfn;
- unsigned long pfn;
-
- block_end_pfn = ALIGN(block_start_pfn + 1, pageblock_nr_pages);
- for (; block_start_pfn < zone_end_pfn(zone);
- block_start_pfn = block_end_pfn,
- block_end_pfn += pageblock_nr_pages) {
-
- block_end_pfn = min(block_end_pfn, zone_end_pfn(zone));
-
- if (!__pageblock_pfn_to_page(block_start_pfn,
- block_end_pfn, zone))
- return;
- }
-
- /* We confirm that there is no hole */
- zone->contiguous = true;
-}
-
-void clear_zone_contiguous(struct zone *zone)
-{
- zone->contiguous = false;
-}
-
#ifdef CONFIG_CMA
/* Free whole pageblock and set its migration type to MIGRATE_CMA. */
void __init init_cma_reserved_pageblock(struct page *page)
_