From b71636e29823c0602d908a2a62e94c9b57a97491 Mon Sep 17 00:00:00 2001 From: Paul Mundt Date: Sun, 15 Jul 2007 23:38:15 -0700 Subject: [PATCH] numa: mempolicy: dynamic interleave map for system init This converts the default system init memory policy to use a dynamically created node map instead of defaulting to all online nodes. Nodes of a certain size (>= 16MB) are judged to be suitable for interleave, and are added to the map. If all nodes are smaller in size, the largest one is automatically selected. Without this, tiny nodes find themselves out of memory before we even make it to userspace. Systems with large nodes will notice no change. Only the system init policy is effected by this change, the regular MPOL_DEFAULT policy is still switched to later on in the boot process as normal. Signed-off-by: Paul Mundt Cc: Andi Kleen Cc: Christoph Lameter Cc: Hugh Dickins Cc: Lee Schermerhorn Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/mempolicy.c | 31 ++++++++++++++++++++++++++++--- 1 file changed, 28 insertions(+), 3 deletions(-) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index d76e8eb342..a67c8f1828 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1597,6 +1597,10 @@ void mpol_free_shared_policy(struct shared_policy *p) /* assumes fs == KERNEL_DS */ void __init numa_policy_init(void) { + nodemask_t interleave_nodes; + unsigned long largest = 0; + int nid, prefer = 0; + policy_cache = kmem_cache_create("numa_policy", sizeof(struct mempolicy), 0, SLAB_PANIC, NULL, NULL); @@ -1605,10 +1609,31 @@ void __init numa_policy_init(void) sizeof(struct sp_node), 0, SLAB_PANIC, NULL, NULL); - /* Set interleaving policy for system init. This way not all - the data structures allocated at system boot end up in node zero. */ + /* + * Set interleaving policy for system init. Interleaving is only + * enabled across suitably sized nodes (default is >= 16MB), or + * fall back to the largest node if they're all smaller. + */ + nodes_clear(interleave_nodes); + for_each_online_node(nid) { + unsigned long total_pages = node_present_pages(nid); + + /* Preserve the largest node */ + if (largest < total_pages) { + largest = total_pages; + prefer = nid; + } + + /* Interleave this node? */ + if ((total_pages << PAGE_SHIFT) >= (16 << 20)) + node_set(nid, interleave_nodes); + } + + /* All too small, use the largest */ + if (unlikely(nodes_empty(interleave_nodes))) + node_set(prefer, interleave_nodes); - if (do_set_mempolicy(MPOL_INTERLEAVE, &node_online_map)) + if (do_set_mempolicy(MPOL_INTERLEAVE, &interleave_nodes)) printk("numa_policy_init: interleaving failed\n"); } -- 2.39.5