diff options
| -rw-r--r-- | Documentation/vm/numa_memory_policy.txt | 16 | ||||
| -rw-r--r-- | mm/mempolicy.c | 42 |
2 files changed, 40 insertions, 18 deletions
diff --git a/Documentation/vm/numa_memory_policy.txt b/Documentation/vm/numa_memory_policy.txt index 706410dfb9e..1c7dd21623d 100644 --- a/Documentation/vm/numa_memory_policy.txt +++ b/Documentation/vm/numa_memory_policy.txt @@ -205,6 +205,12 @@ Components of Memory Policies local allocation for a specific range of addresses--i.e. for VMA policies. + It is possible for the user to specify that local allocation is + always preferred by passing an empty nodemask with this mode. + If an empty nodemask is passed, the policy cannot use the + MPOL_F_STATIC_NODES or MPOL_F_RELATIVE_NODES flags described + below. + MPOL_INTERLEAVED: This mode specifies that page allocations be interleaved, on a page granularity, across the nodes specified in the policy. This mode also behaves slightly differently, based on @@ -254,7 +260,10 @@ Components of Memory Policies occurs over that node. If no nodes from the user's nodemask are now allowed, the Default behavior is used. - MPOL_F_STATIC_NODES cannot be used with MPOL_F_RELATIVE_NODES. + MPOL_F_STATIC_NODES cannot be combined with the + MPOL_F_RELATIVE_NODES flag. It also cannot be used for + MPOL_PREFERRED policies that were created with an empty nodemask + (local allocation). MPOL_F_RELATIVE_NODES: This flag specifies that the nodemask passed by the user will be mapped relative to the set of the task or VMA's @@ -301,7 +310,10 @@ Components of Memory Policies set of memory nodes allowed by the task's cpuset, as that may change over time. - MPOL_F_RELATIVE_NODES cannot be used with MPOL_F_STATIC_NODES. + MPOL_F_RELATIVE_NODES cannot be combined with the + MPOL_F_STATIC_NODES flag. It also cannot be used for + MPOL_PREFERRED policies that were created with an empty nodemask + (local allocation). MEMORY POLICY APIs diff --git a/mm/mempolicy.c b/mm/mempolicy.c index a94d994eaaa..c1b907789d8 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -181,27 +181,43 @@ static struct mempolicy *mpol_new(unsigned short mode, unsigned short flags, { struct mempolicy *policy; nodemask_t cpuset_context_nmask; - int localalloc = 0; int ret; pr_debug("setting mode %d flags %d nodes[0] %lx\n", mode, flags, nodes ? nodes_addr(*nodes)[0] : -1); - if (mode == MPOL_DEFAULT) - return NULL; - if (!nodes || nodes_empty(*nodes)) { - if (mode != MPOL_PREFERRED) + if (mode == MPOL_DEFAULT) { + if (nodes && !nodes_empty(*nodes)) return ERR_PTR(-EINVAL); - localalloc = 1; /* special case: no mode flags */ + return NULL; } + VM_BUG_ON(!nodes); + + /* + * MPOL_PREFERRED cannot be used with MPOL_F_STATIC_NODES or + * MPOL_F_RELATIVE_NODES if the nodemask is empty (local allocation). + * All other modes require a valid pointer to a non-empty nodemask. + */ + if (mode == MPOL_PREFERRED) { + if (nodes_empty(*nodes)) { + if (((flags & MPOL_F_STATIC_NODES) || + (flags & MPOL_F_RELATIVE_NODES))) + return ERR_PTR(-EINVAL); + nodes = NULL; /* flag local alloc */ + } + } else if (nodes_empty(*nodes)) + return ERR_PTR(-EINVAL); policy = kmem_cache_alloc(policy_cache, GFP_KERNEL); if (!policy) return ERR_PTR(-ENOMEM); atomic_set(&policy->refcnt, 1); policy->policy = mode; + policy->flags = flags; - if (!localalloc) { - policy->flags = flags; + if (nodes) { + /* + * cpuset related setup doesn't apply to local allocation + */ cpuset_update_task_memory_state(); if (flags & MPOL_F_RELATIVE_NODES) mpol_relative_nodemask(&cpuset_context_nmask, nodes, @@ -217,7 +233,7 @@ static struct mempolicy *mpol_new(unsigned short mode, unsigned short flags, } ret = mpol_ops[mode].create(policy, - localalloc ? NULL : &cpuset_context_nmask); + nodes ? &cpuset_context_nmask : NULL); if (ret < 0) { kmem_cache_free(policy_cache, policy); return ERR_PTR(ret); @@ -259,10 +275,6 @@ static void mpol_rebind_preferred(struct mempolicy *pol, { nodemask_t tmp; - /* - * check 'STATIC_NODES first, as preferred_node == -1 may be - * a temporary, "fallback" state for this policy. - */ if (pol->flags & MPOL_F_STATIC_NODES) { int node = first_node(pol->w.user_nodemask); @@ -270,12 +282,10 @@ static void mpol_rebind_preferred(struct mempolicy *pol, pol->v.preferred_node = node; else pol->v.preferred_node = -1; - } else if (pol->v.preferred_node == -1) { - return; /* no remap required for explicit local alloc */ } else if (pol->flags & MPOL_F_RELATIVE_NODES) { mpol_relative_nodemask(&tmp, &pol->w.user_nodemask, nodes); pol->v.preferred_node = first_node(tmp); - } else { + } else if (pol->v.preferred_node != -1) { pol->v.preferred_node = node_remap(pol->v.preferred_node, pol->w.cpuset_mems_allowed, *nodes); |