From bad44b5be84cf3bb1ff900bec02ee61e1993328c Mon Sep 17 00:00:00 2001 From: David Rientjes Date: Mon, 14 Dec 2009 17:58:38 -0800 Subject: [PATCH] mm: add gfp flags for NODEMASK_ALLOC slab allocations Objects passed to NODEMASK_ALLOC() are relatively small in size and are backed by slab caches that are not of large order, traditionally never greater than PAGE_ALLOC_COSTLY_ORDER. Thus, using GFP_KERNEL for these allocations on large machines when CONFIG_NODES_SHIFT > 8 will cause the page allocator to loop endlessly in the allocation attempt, each time invoking both direct reclaim or the oom killer. This is of particular interest when using NODEMASK_ALLOC() from a mempolicy context (either directly in mm/mempolicy.c or the mempolicy constrained hugetlb allocations) since the oom killer always kills current when allocations are constrained by mempolicies. So for all present use cases in the kernel, current would end up being oom killed when direct reclaim fails. That would allow the NODEMASK_ALLOC() to succeed but current would have sacrificed itself upon returning. This patch adds gfp flags to NODEMASK_ALLOC() to pass to kmalloc() on CONFIG_NODES_SHIFT > 8; this parameter is a nop on other configurations. All current use cases either directly from hugetlb code or indirectly via NODEMASK_SCRATCH() union __GFP_NORETRY to avoid direct reclaim and the oom killer when the slab allocator needs to allocate additional pages. The side-effect of this change is that all current use cases of either NODEMASK_ALLOC() or NODEMASK_SCRATCH() need appropriate -ENOMEM handling when the allocation fails (never for CONFIG_NODES_SHIFT <= 8). All current use cases were audited and do have appropriate error handling at this time. Signed-off-by: David Rientjes Acked-by: KAMEZAWA Hiroyuki Cc: Lee Schermerhorn Cc: Mel Gorman Cc: Randy Dunlap Cc: Nishanth Aravamudan Cc: Andi Kleen Cc: David Rientjes Cc: Adam Litke Cc: Andy Whitcroft Cc: Eric Whitney Cc: Christoph Lameter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/nodemask.h | 21 ++++++++++++--------- mm/hugetlb.c | 5 +++-- 2 files changed, 15 insertions(+), 11 deletions(-) diff --git a/include/linux/nodemask.h b/include/linux/nodemask.h index cbd521a..454997c 100644 --- a/include/linux/nodemask.h +++ b/include/linux/nodemask.h @@ -485,15 +485,17 @@ static inline int num_node_state(enum node_states state) #define for_each_online_node(node) for_each_node_state(node, N_ONLINE) /* - * For nodemask scrach area.(See CPUMASK_ALLOC() in cpumask.h) - * NODEMASK_ALLOC(x, m) allocates an object of type 'x' with the name 'm'. + * For nodemask scrach area. + * NODEMASK_ALLOC(type, name) allocates an object with a specified type and + * name. */ -#if NODES_SHIFT > 8 /* nodemask_t > 64 bytes */ -#define NODEMASK_ALLOC(x, m) x *m = kmalloc(sizeof(*m), GFP_KERNEL) -#define NODEMASK_FREE(m) kfree(m) +#if NODES_SHIFT > 8 /* nodemask_t > 256 bytes */ +#define NODEMASK_ALLOC(type, name, gfp_flags) \ + type *name = kmalloc(sizeof(*name), gfp_flags) +#define NODEMASK_FREE(m) kfree(m) #else -#define NODEMASK_ALLOC(x, m) x _m, *m = &_m -#define NODEMASK_FREE(m) do {} while (0) +#define NODEMASK_ALLOC(type, name, gfp_flags) type _name, *name = &_name +#define NODEMASK_FREE(m) do {} while (0) #endif /* A example struture for using NODEMASK_ALLOC, used in mempolicy. */ @@ -502,8 +504,9 @@ struct nodemask_scratch { nodemask_t mask2; }; -#define NODEMASK_SCRATCH(x) \ - NODEMASK_ALLOC(struct nodemask_scratch, x) +#define NODEMASK_SCRATCH(x) \ + NODEMASK_ALLOC(struct nodemask_scratch, x, \ + GFP_KERNEL | __GFP_NORETRY) #define NODEMASK_SCRATCH_FREE(x) NODEMASK_FREE(x) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index b4a2635..450493d 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1361,7 +1361,7 @@ static ssize_t nr_hugepages_store_common(bool obey_mempolicy, int nid; unsigned long count; struct hstate *h; - NODEMASK_ALLOC(nodemask_t, nodes_allowed); + NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY); err = strict_strtoul(buf, 10, &count); if (err) @@ -1857,7 +1857,8 @@ static int hugetlb_sysctl_handler_common(bool obey_mempolicy, proc_doulongvec_minmax(table, write, buffer, length, ppos); if (write) { - NODEMASK_ALLOC(nodemask_t, nodes_allowed); + NODEMASK_ALLOC(nodemask_t, nodes_allowed, + GFP_KERNEL | __GFP_NORETRY); if (!(obey_mempolicy && init_nodemask_of_mempolicy(nodes_allowed))) { NODEMASK_FREE(nodes_allowed); -- 1.8.2.3