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Date: Fri, 15 Apr 2016 10:07:52 +0100
From: Mel Gorman <mgorman@...hsingularity.net>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Vlastimil Babka <vbabka@...e.cz>,
Jesper Dangaard Brouer <brouer@...hat.com>,
Linux-MM <linux-mm@...ck.org>,
LKML <linux-kernel@...r.kernel.org>,
Mel Gorman <mgorman@...hsingularity.net>
Subject: [PATCH 25/28] mm, page_alloc: Inline pageblock lookup in page free fast paths
The function call overhead of get_pfnblock_flags_mask() is measurable in
the page free paths. This patch uses an inlined version that is faster.
Signed-off-by: Mel Gorman <mgorman@...hsingularity.net>
---
include/linux/mmzone.h | 7 --
mm/page_alloc.c | 188 ++++++++++++++++++++++++++-----------------------
mm/page_owner.c | 2 +-
mm/vmstat.c | 2 +-
4 files changed, 102 insertions(+), 97 deletions(-)
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index bf153ed097d5..48ee8885aa74 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -85,13 +85,6 @@ extern int page_group_by_mobility_disabled;
get_pfnblock_flags_mask(page, page_to_pfn(page), \
PB_migrate_end, MIGRATETYPE_MASK)
-static inline int get_pfnblock_migratetype(struct page *page, unsigned long pfn)
-{
- BUILD_BUG_ON(PB_migrate_end - PB_migrate != 2);
- return get_pfnblock_flags_mask(page, pfn, PB_migrate_end,
- MIGRATETYPE_MASK);
-}
-
struct free_area {
struct list_head free_list[MIGRATE_TYPES];
unsigned long nr_free;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index bdcd4087553e..f038d06192c7 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -352,6 +352,106 @@ static inline bool update_defer_init(pg_data_t *pgdat,
}
#endif
+/* Return a pointer to the bitmap storing bits affecting a block of pages */
+static inline unsigned long *get_pageblock_bitmap(struct page *page,
+ unsigned long pfn)
+{
+#ifdef CONFIG_SPARSEMEM
+ return __pfn_to_section(pfn)->pageblock_flags;
+#else
+ return page_zone(page)->pageblock_flags;
+#endif /* CONFIG_SPARSEMEM */
+}
+
+static inline int pfn_to_bitidx(struct page *page, unsigned long pfn)
+{
+#ifdef CONFIG_SPARSEMEM
+ pfn &= (PAGES_PER_SECTION-1);
+ return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
+#else
+ pfn = pfn - round_down(page_zone(page)->zone_start_pfn, pageblock_nr_pages);
+ return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
+#endif /* CONFIG_SPARSEMEM */
+}
+
+/**
+ * get_pfnblock_flags_mask - Return the requested group of flags for the pageblock_nr_pages block of pages
+ * @page: The page within the block of interest
+ * @pfn: The target page frame number
+ * @end_bitidx: The last bit of interest to retrieve
+ * @mask: mask of bits that the caller is interested in
+ *
+ * Return: pageblock_bits flags
+ */
+static __always_inline unsigned long __get_pfnblock_flags_mask(struct page *page,
+ unsigned long pfn,
+ unsigned long end_bitidx,
+ unsigned long mask)
+{
+ unsigned long *bitmap;
+ unsigned long bitidx, word_bitidx;
+ unsigned long word;
+
+ bitmap = get_pageblock_bitmap(page, pfn);
+ bitidx = pfn_to_bitidx(page, pfn);
+ word_bitidx = bitidx / BITS_PER_LONG;
+ bitidx &= (BITS_PER_LONG-1);
+
+ word = bitmap[word_bitidx];
+ bitidx += end_bitidx;
+ return (word >> (BITS_PER_LONG - bitidx - 1)) & mask;
+}
+
+unsigned long get_pfnblock_flags_mask(struct page *page, unsigned long pfn,
+ unsigned long end_bitidx,
+ unsigned long mask)
+{
+ return __get_pfnblock_flags_mask(page, pfn, end_bitidx, mask);
+}
+
+static __always_inline int get_pfnblock_migratetype(struct page *page, unsigned long pfn)
+{
+ return __get_pfnblock_flags_mask(page, pfn, PB_migrate_end, MIGRATETYPE_MASK);
+}
+
+/**
+ * set_pfnblock_flags_mask - Set the requested group of flags for a pageblock_nr_pages block of pages
+ * @page: The page within the block of interest
+ * @flags: The flags to set
+ * @pfn: The target page frame number
+ * @end_bitidx: The last bit of interest
+ * @mask: mask of bits that the caller is interested in
+ */
+void set_pfnblock_flags_mask(struct page *page, unsigned long flags,
+ unsigned long pfn,
+ unsigned long end_bitidx,
+ unsigned long mask)
+{
+ unsigned long *bitmap;
+ unsigned long bitidx, word_bitidx;
+ unsigned long old_word, word;
+
+ BUILD_BUG_ON(NR_PAGEBLOCK_BITS != 4);
+
+ bitmap = get_pageblock_bitmap(page, pfn);
+ bitidx = pfn_to_bitidx(page, pfn);
+ word_bitidx = bitidx / BITS_PER_LONG;
+ bitidx &= (BITS_PER_LONG-1);
+
+ VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn), page);
+
+ bitidx += end_bitidx;
+ mask <<= (BITS_PER_LONG - bitidx - 1);
+ flags <<= (BITS_PER_LONG - bitidx - 1);
+
+ word = READ_ONCE(bitmap[word_bitidx]);
+ for (;;) {
+ old_word = cmpxchg(&bitmap[word_bitidx], word, (word & ~mask) | flags);
+ if (word == old_word)
+ break;
+ word = old_word;
+ }
+}
void set_pageblock_migratetype(struct page *page, int migratetype)
{
@@ -6801,94 +6901,6 @@ void *__init alloc_large_system_hash(const char *tablename,
return table;
}
-/* Return a pointer to the bitmap storing bits affecting a block of pages */
-static inline unsigned long *get_pageblock_bitmap(struct page *page,
- unsigned long pfn)
-{
-#ifdef CONFIG_SPARSEMEM
- return __pfn_to_section(pfn)->pageblock_flags;
-#else
- return page_zone(page)->pageblock_flags;
-#endif /* CONFIG_SPARSEMEM */
-}
-
-static inline int pfn_to_bitidx(struct page *page, unsigned long pfn)
-{
-#ifdef CONFIG_SPARSEMEM
- pfn &= (PAGES_PER_SECTION-1);
- return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
-#else
- pfn = pfn - round_down(page_zone(page)->zone_start_pfn, pageblock_nr_pages);
- return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
-#endif /* CONFIG_SPARSEMEM */
-}
-
-/**
- * get_pfnblock_flags_mask - Return the requested group of flags for the pageblock_nr_pages block of pages
- * @page: The page within the block of interest
- * @pfn: The target page frame number
- * @end_bitidx: The last bit of interest to retrieve
- * @mask: mask of bits that the caller is interested in
- *
- * Return: pageblock_bits flags
- */
-unsigned long get_pfnblock_flags_mask(struct page *page, unsigned long pfn,
- unsigned long end_bitidx,
- unsigned long mask)
-{
- unsigned long *bitmap;
- unsigned long bitidx, word_bitidx;
- unsigned long word;
-
- bitmap = get_pageblock_bitmap(page, pfn);
- bitidx = pfn_to_bitidx(page, pfn);
- word_bitidx = bitidx / BITS_PER_LONG;
- bitidx &= (BITS_PER_LONG-1);
-
- word = bitmap[word_bitidx];
- bitidx += end_bitidx;
- return (word >> (BITS_PER_LONG - bitidx - 1)) & mask;
-}
-
-/**
- * set_pfnblock_flags_mask - Set the requested group of flags for a pageblock_nr_pages block of pages
- * @page: The page within the block of interest
- * @flags: The flags to set
- * @pfn: The target page frame number
- * @end_bitidx: The last bit of interest
- * @mask: mask of bits that the caller is interested in
- */
-void set_pfnblock_flags_mask(struct page *page, unsigned long flags,
- unsigned long pfn,
- unsigned long end_bitidx,
- unsigned long mask)
-{
- unsigned long *bitmap;
- unsigned long bitidx, word_bitidx;
- unsigned long old_word, word;
-
- BUILD_BUG_ON(NR_PAGEBLOCK_BITS != 4);
-
- bitmap = get_pageblock_bitmap(page, pfn);
- bitidx = pfn_to_bitidx(page, pfn);
- word_bitidx = bitidx / BITS_PER_LONG;
- bitidx &= (BITS_PER_LONG-1);
-
- VM_BUG_ON_PAGE(!zone_spans_pfn(page_zone(page), pfn), page);
-
- bitidx += end_bitidx;
- mask <<= (BITS_PER_LONG - bitidx - 1);
- flags <<= (BITS_PER_LONG - bitidx - 1);
-
- word = READ_ONCE(bitmap[word_bitidx]);
- for (;;) {
- old_word = cmpxchg(&bitmap[word_bitidx], word, (word & ~mask) | flags);
- if (word == old_word)
- break;
- word = old_word;
- }
-}
-
/*
* This function checks whether pageblock includes unmovable pages or not.
* If @count is not zero, it is okay to include less @count unmovable pages
diff --git a/mm/page_owner.c b/mm/page_owner.c
index ac3d8d129974..22630e75c192 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -143,7 +143,7 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn,
goto err;
/* Print information relevant to grouping pages by mobility */
- pageblock_mt = get_pfnblock_migratetype(page, pfn);
+ pageblock_mt = get_pageblock_migratetype(page);
page_mt = gfpflags_to_migratetype(page_ext->gfp_mask);
ret += snprintf(kbuf + ret, count - ret,
"PFN %lu type %s Block %lu type %s Flags %#lx(%pGp)\n",
diff --git a/mm/vmstat.c b/mm/vmstat.c
index a4bda11eac8d..20698fc82354 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1044,7 +1044,7 @@ static void pagetypeinfo_showmixedcount_print(struct seq_file *m,
block_end_pfn = min(block_end_pfn, end_pfn);
page = pfn_to_page(pfn);
- pageblock_mt = get_pfnblock_migratetype(page, pfn);
+ pageblock_mt = get_pageblock_migratetype(page);
for (; pfn < block_end_pfn; pfn++) {
if (!pfn_valid_within(pfn))
--
2.6.4
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