Messages in this thread Patch in this message | | | Subject | Re: [PATCH] break out zone free list initialization | From | Dave Hansen <> | Date | Wed, 28 Jul 2004 10:23:21 -0700 |
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On Wed, 2004-07-28 at 10:09, Dave Hansen wrote: > The following patch removes the individual free area initialization from > free_area_init_core(), and puts it in a new function > zone_init_free_lists(). It also creates pages_to_bitmap_size(), which > is then used in zone_init_free_lists() as well as several times in my > free area bitmap resizing patch. > > First of all, I think it looks nicer this way, but it's also necessary > to have this if you want to initialize a zone after system boot, like if > a NUMA node was hot-added. In any case, it should be functionally > equivalent to the old code. > > Compiles and boots on x86. I've been running with this for a few weeks, > and haven't seen any problems with it yet.
OK, I suck. Here's one that applies with -p1 properly and doesn't add whitespace on the line above the zone_init_free_lists() call.
page_alloc.c | 84 +++++++++++++++++++++++++++++++++-------------------------- 1 files changed, 47 insertions(+), 37 deletions(-)
-- Dave --- linux-2.6.8-rc1-mm1.work/mm/page_alloc.c.orig 2004-07-28 10:04:56.000000000 -0700 +++ linux-2.6.8-rc1-mm1.work/mm/page_alloc.c 2004-07-28 10:09:09.000000000 -0700 @@ -1413,6 +1413,52 @@ } } +/* + * Page buddy system uses "index >> (i+1)", where "index" is + * at most "size-1". + * + * The extra "+3" is to round down to byte size (8 bits per byte + * assumption). Thus we get "(size-1) >> (i+4)" as the last byte + * we can access. + * + * The "+1" is because we want to round the byte allocation up + * rather than down. So we should have had a "+7" before we shifted + * down by three. Also, we have to add one as we actually _use_ the + * last bit (it's [0,n] inclusive, not [0,n[). + * + * So we actually had +7+1 before we shift down by 3. But + * (n+8) >> 3 == (n >> 3) + 1 (modulo overflows, which we do not have). + * + * Finally, we LONG_ALIGN because all bitmap operations are on longs. + */ +unsigned long pages_to_bitmap_size(unsigned long order, unsigned long nr_pages) +{ + unsigned long bitmap_size; + + bitmap_size = (nr_pages-1) >> (order+4); + bitmap_size = LONG_ALIGN(bitmap_size+1); + + return bitmap_size; +} + +void zone_init_free_lists(struct pglist_data *pgdat, struct zone *zone, unsigned long size) +{ + int order; + for (order = 0; ; order++) { + unsigned long bitmap_size; + + INIT_LIST_HEAD(&zone->free_area[order].free_list); + if (order == MAX_ORDER-1) { + zone->free_area[order].map = NULL; + break; + } + + bitmap_size = pages_to_bitmap_size(order, size); + zone->free_area[order].map = + (unsigned long *) alloc_bootmem_node(pgdat, bitmap_size); + } +} + #ifndef __HAVE_ARCH_MEMMAP_INIT #define memmap_init(start, size, nid, zone, start_pfn) \ memmap_init_zone((start), (size), (nid), (zone), (start_pfn)) @@ -1529,43 +1575,7 @@ zone_start_pfn += size; lmem_map += size; - for (i = 0; ; i++) { - unsigned long bitmap_size; - - INIT_LIST_HEAD(&zone->free_area[i].free_list); - if (i == MAX_ORDER-1) { - zone->free_area[i].map = NULL; - break; - } - - /* - * Page buddy system uses "index >> (i+1)", - * where "index" is at most "size-1". - * - * The extra "+3" is to round down to byte - * size (8 bits per byte assumption). Thus - * we get "(size-1) >> (i+4)" as the last byte - * we can access. - * - * The "+1" is because we want to round the - * byte allocation up rather than down. So - * we should have had a "+7" before we shifted - * down by three. Also, we have to add one as - * we actually _use_ the last bit (it's [0,n] - * inclusive, not [0,n[). - * - * So we actually had +7+1 before we shift - * down by 3. But (n+8) >> 3 == (n >> 3) + 1 - * (modulo overflows, which we do not have). - * - * Finally, we LONG_ALIGN because all bitmap - * operations are on longs. - */ - bitmap_size = (size-1) >> (i+4); - bitmap_size = LONG_ALIGN(bitmap_size+1); - zone->free_area[i].map = - (unsigned long *) alloc_bootmem_node(pgdat, bitmap_size); - } + zone_init_free_lists(pgdat, zone, zone->spanned_pages); } } | |