From: grgustaf@redhat.com Subject: [RHEL5.1 PATCH] sparsemem memmap allocation above 4G (bz 227426) Date: Wed, 6 Jun 2007 17:34:44 -0400 Bugzilla: 227426 Message-Id: <20070606213444.GA29230@samurai.boston.redhat.com> Changelog: [x86_64] sparsemem memmap allocation above 4G This patch went upstream last Friday. Some Intel folks suggested it may solve this install panic bugzilla on a machine w/ 64GB of RAM. I should be able to get one of the folks with this large memory setup at Intel to test for me this week. I'm not sure if we need the kernel on the install CD to reproduce this exact BZ though. Larry, do you think this could solve that problem? Patch notes from Nanhai Zou: On systems with a huge amount of physical memory, VFS cache and memory memmap may eat all available system memory under 4G, then the system may fail to allocate swiotlb bounce buffer. There was a fix for this issue in arch/x86_64/mm/numa.c, but that fix doesn't cover sparsemem model. This patch add fix to sparsemem model by first trying to allocate memmap above 4G. - Geoff Index: linux-2.6.18.x86_64/arch/x86_64/mm/init.c =================================================================== --- linux-2.6.18.x86_64.orig/arch/x86_64/mm/init.c 2007-06-05 18:45:40.000000000 -0400 +++ linux-2.6.18.x86_64/arch/x86_64/mm/init.c 2007-06-06 16:30:32.000000000 -0400 @@ -877,3 +877,9 @@ int in_gate_area_no_task(unsigned long a { return (addr >= VSYSCALL_START) && (addr < VSYSCALL_END); } + +void *alloc_bootmem_high_node(pg_data_t *pgdat, unsigned long size) +{ + return __alloc_bootmem_core(pgdat->bdata, size, + SMP_CACHE_BYTES, (4UL*1024*1024*1024), 0); +} Index: linux-2.6.18.x86_64/include/linux/bootmem.h =================================================================== --- linux-2.6.18.x86_64.orig/include/linux/bootmem.h 2006-09-19 23:42:06.000000000 -0400 +++ linux-2.6.18.x86_64/include/linux/bootmem.h 2007-06-06 16:32:05.000000000 -0400 @@ -56,6 +56,8 @@ extern void * __init __alloc_bootmem_low extern void * __init __alloc_bootmem_core(struct bootmem_data *bdata, unsigned long size, unsigned long align, unsigned long goal, unsigned long limit); +extern void *alloc_bootmem_high_node(pg_data_t *pgdat, unsigned long size); + #ifndef CONFIG_HAVE_ARCH_BOOTMEM_NODE extern void __init reserve_bootmem (unsigned long addr, unsigned long size); #define alloc_bootmem(x) \ Index: linux-2.6.18.x86_64/mm/sparse.c =================================================================== --- linux-2.6.18.x86_64.orig/mm/sparse.c 2007-06-05 18:45:37.000000000 -0400 +++ linux-2.6.18.x86_64/mm/sparse.c 2007-06-06 16:33:47.000000000 -0400 @@ -186,6 +186,12 @@ static int sparse_init_one_section(struc return 1; } +__attribute__((weak)) +void *alloc_bootmem_high_node(pg_data_t *pgdat, unsigned long size) +{ + return NULL; +} + static struct page *sparse_early_mem_map_alloc(unsigned long pnum) { struct page *map; @@ -196,6 +202,11 @@ static struct page *sparse_early_mem_map if (map) return map; + map = alloc_bootmem_high_node(NODE_DATA(nid), + sizeof(struct page) * PAGES_PER_SECTION); + if (map) + return map; + map = alloc_bootmem_node(NODE_DATA(nid), sizeof(struct page) * PAGES_PER_SECTION); if (map)