Enable system hashtable memory to be distributed among nodes on x86_64 NUMA
Forcing the kernel to use node interleaved vmalloc instead of bootmem for the system hashtable memory (alloc_large_system_hash) reduces the memory imbalance on node 0 by around 40MB on a 8 node x86_64 NUMA box: Before the following patch, on bootup of a 8 node box: Node 0 MemTotal: 3407488 kB Node 0 MemFree: 3206296 kB Node 0 MemUsed: 201192 kB Node 0 Active: 7012 kB Node 0 Inactive: 512 kB Node 0 Dirty: 0 kB Node 0 Writeback: 0 kB Node 0 FilePages: 1912 kB Node 0 Mapped: 420 kB Node 0 AnonPages: 5612 kB Node 0 PageTables: 468 kB Node 0 NFS_Unstable: 0 kB Node 0 Bounce: 0 kB Node 0 Slab: 5408 kB Node 0 SReclaimable: 644 kB Node 0 SUnreclaim: 4764 kB After the patch (or using hashdist=1 on the kernel command line): Node 0 MemTotal: 3407488 kB Node 0 MemFree: 3247608 kB Node 0 MemUsed: 159880 kB Node 0 Active: 3012 kB Node 0 Inactive: 616 kB Node 0 Dirty: 0 kB Node 0 Writeback: 0 kB Node 0 FilePages: 2424 kB Node 0 Mapped: 380 kB Node 0 AnonPages: 1200 kB Node 0 PageTables: 396 kB Node 0 NFS_Unstable: 0 kB Node 0 Bounce: 0 kB Node 0 Slab: 6304 kB Node 0 SReclaimable: 1596 kB Node 0 SUnreclaim: 4708 kB I guess it is a good idea to keep HASHDIST_DEFAULT "on" for x86_64 NUMA since x86_64 has no dearth of vmalloc space? Or maybe enable hash distribution for all 64bit NUMA arches? The following patch does it only for x86_64. Signed-off-by: Pravin B. Shelar <[EMAIL PROTECTED]> Signed-off-by: Ravikiran Thirumalai <[EMAIL PROTECTED]> Signed-off-by: Shai Fultheim <[EMAIL PROTECTED]> Index: linux-2.6.20-rc1/include/linux/bootmem.h =================================================================== --- linux-2.6.20-rc1.orig/include/linux/bootmem.h 2006-12-21 14:34:36.321610875 -0800 +++ linux-2.6.20-rc1/include/linux/bootmem.h 2006-12-26 15:55:04.501064560 -0800 @@ -122,9 +122,9 @@ extern void *alloc_large_system_hash(con #define HASH_EARLY 0x00000001 /* Allocating during early boot? */ /* Only NUMA needs hash distribution. - * IA64 is known to have sufficient vmalloc space. + * IA64 and x86_64 have sufficient vmalloc space. */ -#if defined(CONFIG_NUMA) && defined(CONFIG_IA64) +#if defined(CONFIG_NUMA) && (defined(CONFIG_IA64) || defined(CONFIG_X86_64)) #define HASHDIST_DEFAULT 1 #else #define HASHDIST_DEFAULT 0 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
