From: Wei Yang <richard.weiyang@gmail.com>
To: linux-mm@kvack.org
Cc: akpm@linux-foundation.org, mhocko@suse.com,
Wei Yang <richard.weiyang@gmail.com>
Subject: [PATCH] mm, page_alloc: cleanup usemap_size() when SPARSEMEM is not set
Date: Sat, 19 Jan 2019 07:49:05 +0800 [thread overview]
Message-ID: <20190118234905.27597-1-richard.weiyang@gmail.com> (raw)
Two cleanups in this patch:
* since pageblock_nr_pages == (1 << pageblock_order), the roundup()
and right shift pageblock_order could be replaced with
DIV_ROUND_UP()
* use BITS_TO_LONGS() to get number of bytes for bitmap
This patch also fix one typo in comment.
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
---
mm/page_alloc.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index d295c9bc01a8..d7073cedd087 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6352,7 +6352,7 @@ static void __init calculate_node_totalpages(struct pglist_data *pgdat,
/*
* Calculate the size of the zone->blockflags rounded to an unsigned long
* Start by making sure zonesize is a multiple of pageblock_order by rounding
- * up. Then use 1 NR_PAGEBLOCK_BITS worth of bits per pageblock, finally
+ * up. Then use 1 NR_PAGEBLOCK_BITS width of bits per pageblock, finally
* round what is now in bits to nearest long in bits, then return it in
* bytes.
*/
@@ -6361,12 +6361,9 @@ static unsigned long __init usemap_size(unsigned long zone_start_pfn, unsigned l
unsigned long usemapsize;
zonesize += zone_start_pfn & (pageblock_nr_pages-1);
- usemapsize = roundup(zonesize, pageblock_nr_pages);
- usemapsize = usemapsize >> pageblock_order;
+ usemapsize = DIV_ROUND_UP(zonesize, pageblock_nr_pages);
usemapsize *= NR_PAGEBLOCK_BITS;
- usemapsize = roundup(usemapsize, 8 * sizeof(unsigned long));
-
- return usemapsize / 8;
+ return BITS_TO_LONGS(usemapsize) * sizeof(unsigned long);
}
static void __ref setup_usemap(struct pglist_data *pgdat,
--
2.15.1
next reply other threads:[~2019-01-18 23:49 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-18 23:49 Wei Yang [this message]
2019-01-22 8:55 ` [PATCH] mm, page_alloc: cleanup usemap_size() when SPARSEMEM is not set Michal Hocko
2019-01-22 15:07 ` Wei Yang
2019-01-22 15:16 ` Michal Hocko
2019-01-22 15:56 ` Wei Yang
2019-01-23 9:55 ` Michal Hocko
2019-01-24 14:13 ` Wei Yang
2019-01-24 14:30 ` Michal Hocko
2019-01-25 1:12 ` Wei Yang
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