On Wed, Dec 05, 2018 at 05:19:05PM +0800, Wei Yang wrote: >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. Patch 1 maybe controversial, how about this one :-) Look forward some comments. > >Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx> >--- > 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 7c745c305332..baf473f80800 100644 >--- a/mm/page_alloc.c >+++ b/mm/page_alloc.c >@@ -6204,7 +6204,7 @@ static void __meminit 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. > */ >@@ -6213,12 +6213,9 @@ 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 -- Wei Yang Help you, Help me
