From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: [PATCH] break out zone free list initialization From: Dave Hansen Content-Type: multipart/mixed; boundary="=-z7QDieYcsCXADgcXiyPV" Message-Id: <1091034585.2871.142.camel@nighthawk> Mime-Version: 1.0 Date: Wed, 28 Jul 2004 10:09:45 -0700 Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: William Lee Irwin III , linux-mm , Linux Kernel Mailing List List-ID: --=-z7QDieYcsCXADgcXiyPV Content-Type: text/plain Content-Transfer-Encoding: 7bit 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. page_alloc.c | 86 ++++++++++++++++++++++++++++++++--------------------------- 1 files changed, 48 insertions(+), 38 deletions(-) -- Dave --=-z7QDieYcsCXADgcXiyPV Content-Disposition: attachment; filename=zoneinit_cleanup-2.6.8-rc1-mm1-0.patch Content-Type: text/x-patch; name=zoneinit_cleanup-2.6.8-rc1-mm1-0.patch; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 7bit --- mm/page_alloc.c.orig 2004-07-28 09:37:46.000000000 -0700 +++ mm/page_alloc.c 2004-07-28 09:45:18.000000000 -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)) @@ -1528,44 +1574,8 @@ 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); } } --=-z7QDieYcsCXADgcXiyPV-- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: aart@kvack.org