diff --git a/include/linux/nodemask.h b/include/linux/nodemask.h index 829b94b156f28ec0ed7c0d8dbc2dfeab4ea6825b..b359c4a9ec9e8decdaef46083c78d045dc5d156e 100644 --- a/include/linux/nodemask.h +++ b/include/linux/nodemask.h @@ -82,6 +82,12 @@ * to generate slightly worse code. So use a simple one-line #define * for node_isset(), instead of wrapping an inline inside a macro, the * way we do the other calls. + * + * NODEMASK_SCRATCH + * When doing above logical AND, OR, XOR, Remap operations the callers tend to + * need temporary nodemask_t's on the stack. But if NODES_SHIFT is large, + * nodemask_t's consume too much stack space. NODEMASK_SCRATCH is a helper + * for such situations. See below and CPUMASK_ALLOC also. */ #include @@ -473,4 +479,26 @@ static inline int num_node_state(enum node_states state) #define for_each_node(node) for_each_node_state(node, N_POSSIBLE) #define for_each_online_node(node) for_each_node_state(node, N_ONLINE) +/* + * For nodemask scrach area.(See CPUMASK_ALLOC() in cpumask.h) + */ + +#if NODES_SHIFT > 8 /* nodemask_t > 64 bytes */ +#define NODEMASK_ALLOC(x, m) struct x *m = kmalloc(sizeof(*m), GFP_KERNEL) +#define NODEMASK_FREE(m) kfree(m) +#else +#define NODEMASK_ALLOC(x, m) struct x _m, *m = &_m +#define NODEMASK_FREE(m) +#endif + +/* A example struture for using NODEMASK_ALLOC, used in mempolicy. */ +struct nodemask_scratch { + nodemask_t mask1; + nodemask_t mask2; +}; + +#define NODEMASK_SCRATCH(x) NODEMASK_ALLOC(nodemask_scratch, x) +#define NODEMASK_SCRATCH_FREE(x) NODEMASK_FREE(x) + + #endif /* __LINUX_NODEMASK_H */ diff --git a/mm/mempolicy.c b/mm/mempolicy.c index e08e2c4da63a5dc45bfcfb9f56cd440d557d0772..7dd9d9f806948e23a7f0be04dac209bfc1c584f5 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -191,25 +191,27 @@ static int mpol_new_bind(struct mempolicy *pol, const nodemask_t *nodes) * Must be called holding task's alloc_lock to protect task's mems_allowed * and mempolicy. May also be called holding the mmap_semaphore for write. */ -static int mpol_set_nodemask(struct mempolicy *pol, const nodemask_t *nodes) +static int mpol_set_nodemask(struct mempolicy *pol, + const nodemask_t *nodes, struct nodemask_scratch *nsc) { - nodemask_t cpuset_context_nmask; int ret; /* if mode is MPOL_DEFAULT, pol is NULL. This is right. */ if (pol == NULL) return 0; + /* Check N_HIGH_MEMORY */ + nodes_and(nsc->mask1, + cpuset_current_mems_allowed, node_states[N_HIGH_MEMORY]); VM_BUG_ON(!nodes); if (pol->mode == MPOL_PREFERRED && nodes_empty(*nodes)) nodes = NULL; /* explicit local allocation */ else { if (pol->flags & MPOL_F_RELATIVE_NODES) - mpol_relative_nodemask(&cpuset_context_nmask, nodes, - &cpuset_current_mems_allowed); + mpol_relative_nodemask(&nsc->mask2, nodes,&nsc->mask1); else - nodes_and(cpuset_context_nmask, *nodes, - cpuset_current_mems_allowed); + nodes_and(nsc->mask2, *nodes, nsc->mask1); + if (mpol_store_user_nodemask(pol)) pol->w.user_nodemask = *nodes; else @@ -217,8 +219,10 @@ static int mpol_set_nodemask(struct mempolicy *pol, const nodemask_t *nodes) cpuset_current_mems_allowed; } - ret = mpol_ops[pol->mode].create(pol, - nodes ? &cpuset_context_nmask : NULL); + if (nodes) + ret = mpol_ops[pol->mode].create(pol, &nsc->mask2); + else + ret = mpol_ops[pol->mode].create(pol, NULL); return ret; } @@ -620,12 +624,17 @@ static long do_set_mempolicy(unsigned short mode, unsigned short flags, { struct mempolicy *new, *old; struct mm_struct *mm = current->mm; + NODEMASK_SCRATCH(scratch); int ret; - new = mpol_new(mode, flags, nodes); - if (IS_ERR(new)) - return PTR_ERR(new); + if (!scratch) + return -ENOMEM; + new = mpol_new(mode, flags, nodes); + if (IS_ERR(new)) { + ret = PTR_ERR(new); + goto out; + } /* * prevent changing our mempolicy while show_numa_maps() * is using it. @@ -635,13 +644,13 @@ static long do_set_mempolicy(unsigned short mode, unsigned short flags, if (mm) down_write(&mm->mmap_sem); task_lock(current); - ret = mpol_set_nodemask(new, nodes); + ret = mpol_set_nodemask(new, nodes, scratch); if (ret) { task_unlock(current); if (mm) up_write(&mm->mmap_sem); mpol_put(new); - return ret; + goto out; } old = current->mempolicy; current->mempolicy = new; @@ -654,7 +663,10 @@ static long do_set_mempolicy(unsigned short mode, unsigned short flags, up_write(&mm->mmap_sem); mpol_put(old); - return 0; + ret = 0; +out: + NODEMASK_SCRATCH_FREE(scratch); + return ret; } /* @@ -1014,12 +1026,20 @@ static long do_mbind(unsigned long start, unsigned long len, if (err) return err; } - down_write(&mm->mmap_sem); - task_lock(current); - err = mpol_set_nodemask(new, nmask); - task_unlock(current); + { + NODEMASK_SCRATCH(scratch); + if (scratch) { + down_write(&mm->mmap_sem); + task_lock(current); + err = mpol_set_nodemask(new, nmask, scratch); + task_unlock(current); + if (err) + up_write(&mm->mmap_sem); + } else + err = -ENOMEM; + NODEMASK_SCRATCH_FREE(scratch); + } if (err) { - up_write(&mm->mmap_sem); mpol_put(new); return err; } @@ -1891,6 +1911,7 @@ static int shared_policy_replace(struct shared_policy *sp, unsigned long start, * Install non-NULL @mpol in inode's shared policy rb-tree. * On entry, the current task has a reference on a non-NULL @mpol. * This must be released on exit. + * This is called at get_inode() calls and we can use GFP_KERNEL. */ void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol) { @@ -1902,19 +1923,24 @@ void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol) if (mpol) { struct vm_area_struct pvma; struct mempolicy *new; + NODEMASK_SCRATCH(scratch); + if (!scratch) + return; /* contextualize the tmpfs mount point mempolicy */ new = mpol_new(mpol->mode, mpol->flags, &mpol->w.user_nodemask); if (IS_ERR(new)) { mpol_put(mpol); /* drop our ref on sb mpol */ + NODEMASK_SCRATCH_FREE(scratch); return; /* no valid nodemask intersection */ } task_lock(current); - ret = mpol_set_nodemask(new, &mpol->w.user_nodemask); + ret = mpol_set_nodemask(new, &mpol->w.user_nodemask, scratch); task_unlock(current); mpol_put(mpol); /* drop our ref on sb mpol */ if (ret) { + NODEMASK_SCRATCH_FREE(scratch); mpol_put(new); return; } @@ -1924,6 +1950,7 @@ void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol) pvma.vm_end = TASK_SIZE; /* policy covers entire file */ mpol_set_shared_policy(sp, &pvma, new); /* adds ref */ mpol_put(new); /* drop initial ref */ + NODEMASK_SCRATCH_FREE(scratch); } } @@ -2140,13 +2167,18 @@ int mpol_parse_str(char *str, struct mempolicy **mpol, int no_context) err = 1; else { int ret; - - task_lock(current); - ret = mpol_set_nodemask(new, &nodes); - task_unlock(current); - if (ret) + NODEMASK_SCRATCH(scratch); + if (scratch) { + task_lock(current); + ret = mpol_set_nodemask(new, &nodes, scratch); + task_unlock(current); + } else + ret = -ENOMEM; + NODEMASK_SCRATCH_FREE(scratch); + if (ret) { err = 1; - else if (no_context) { + mpol_put(new); + } else if (no_context) { /* save for contextualization */ new->w.user_nodemask = nodes; }