From: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> MPOL_PREFERRED honors only a single node set in the nodemask. Add the bare define for a new mode which will allow more than one. The patch does all the plumbing without actually adding the new policy type. v2: Plumb most MPOL_PREFERRED_MANY without exposing UAPI (Ben) Fixes for checkpatch (Ben) Link: https://lore.kernel.org/r/20200630212517.308045-4-ben.widawsky@xxxxxxxxx Co-developed-by: Ben Widawsky <ben.widawsky@xxxxxxxxx> Signed-off-by: Ben Widawsky <ben.widawsky@xxxxxxxxx> Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> --- mm/mempolicy.c | 46 ++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 40 insertions(+), 6 deletions(-) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index ba3bc4f28d27..21a6f80f91a9 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -31,6 +31,9 @@ * but useful to set in a VMA when you have a non default * process policy. * + * preferred many Try a set of nodes first before normal fallback. This is + * similar to preferred without the special case. + * * default Allocate on the local node first, or when on a VMA * use the process policy. This is what Linux always did * in a NUMA aware kernel and still does by, ahem, default. @@ -105,6 +108,8 @@ #include "internal.h" +#define MPOL_PREFERRED_MANY MPOL_MAX + /* Internal flags */ #define MPOL_MF_DISCONTIG_OK (MPOL_MF_INTERNAL << 0) /* Skip checks for continuous vmas */ #define MPOL_MF_INVERT (MPOL_MF_INTERNAL << 1) /* Invert check for nodemask */ @@ -175,7 +180,7 @@ struct mempolicy *get_task_policy(struct task_struct *p) static const struct mempolicy_operations { int (*create)(struct mempolicy *pol, const nodemask_t *nodes); void (*rebind)(struct mempolicy *pol, const nodemask_t *nodes); -} mpol_ops[MPOL_MAX]; +} mpol_ops[MPOL_MAX + 1]; static inline int mpol_store_user_nodemask(const struct mempolicy *pol) { @@ -415,7 +420,7 @@ void mpol_rebind_mm(struct mm_struct *mm, nodemask_t *new) mmap_write_unlock(mm); } -static const struct mempolicy_operations mpol_ops[MPOL_MAX] = { +static const struct mempolicy_operations mpol_ops[MPOL_MAX + 1] = { [MPOL_DEFAULT] = { .rebind = mpol_rebind_default, }, @@ -432,6 +437,10 @@ static const struct mempolicy_operations mpol_ops[MPOL_MAX] = { .rebind = mpol_rebind_nodemask, }, /* [MPOL_LOCAL] - see mpol_new() */ + [MPOL_PREFERRED_MANY] = { + .create = NULL, + .rebind = NULL, + }, }; static int migrate_page_add(struct page *page, struct list_head *pagelist, @@ -914,6 +923,9 @@ static void get_policy_nodemask(struct mempolicy *p, nodemask_t *nodes) case MPOL_INTERLEAVE: *nodes = p->v.nodes; break; + case MPOL_PREFERRED_MANY: + *nodes = p->v.preferred_nodes; + break; case MPOL_PREFERRED: if (!(p->flags & MPOL_F_LOCAL)) *nodes = p->v.preferred_nodes; @@ -1889,7 +1901,9 @@ nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *policy) /* Return the node id preferred by the given mempolicy, or the given id */ static int policy_node(gfp_t gfp, struct mempolicy *policy, int nd) { - if (policy->mode == MPOL_PREFERRED && !(policy->flags & MPOL_F_LOCAL)) { + if ((policy->mode == MPOL_PREFERRED || + policy->mode == MPOL_PREFERRED_MANY) && + !(policy->flags & MPOL_F_LOCAL)) { nd = first_node(policy->v.preferred_nodes); } else { /* @@ -1932,6 +1946,7 @@ unsigned int mempolicy_slab_node(void) return node; switch (policy->mode) { + case MPOL_PREFERRED_MANY: case MPOL_PREFERRED: /* * handled MPOL_F_LOCAL above @@ -2066,6 +2081,9 @@ bool init_nodemask_of_mempolicy(nodemask_t *mask) task_lock(current); mempolicy = current->mempolicy; switch (mempolicy->mode) { + case MPOL_PREFERRED_MANY: + *mask = mempolicy->v.preferred_nodes; + break; case MPOL_PREFERRED: if (mempolicy->flags & MPOL_F_LOCAL) nid = numa_node_id(); @@ -2120,6 +2138,9 @@ bool mempolicy_nodemask_intersects(struct task_struct *tsk, * nodes in mask. */ break; + case MPOL_PREFERRED_MANY: + ret = nodes_intersects(mempolicy->v.preferred_nodes, *mask); + break; case MPOL_BIND: case MPOL_INTERLEAVE: ret = nodes_intersects(mempolicy->v.nodes, *mask); @@ -2204,10 +2225,13 @@ alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma, * node and don't fall back to other nodes, as the cost of * remote accesses would likely offset THP benefits. * - * If the policy is interleave, or does not allow the current - * node in its nodemask, we allocate the standard way. + * If the policy is interleave or multiple preferred nodes, or + * does not allow the current node in its nodemask, we allocate + * the standard way. */ - if (pol->mode == MPOL_PREFERRED && !(pol->flags & MPOL_F_LOCAL)) + if ((pol->mode == MPOL_PREFERRED || + pol->mode == MPOL_PREFERRED_MANY) && + !(pol->flags & MPOL_F_LOCAL)) hpage_node = first_node(pol->v.preferred_nodes); nmask = policy_nodemask(gfp, pol); @@ -2343,6 +2367,9 @@ bool __mpol_equal(struct mempolicy *a, struct mempolicy *b) case MPOL_BIND: case MPOL_INTERLEAVE: return !!nodes_equal(a->v.nodes, b->v.nodes); + case MPOL_PREFERRED_MANY: + return !!nodes_equal(a->v.preferred_nodes, + b->v.preferred_nodes); case MPOL_PREFERRED: /* a's ->flags is the same as b's */ if (a->flags & MPOL_F_LOCAL) @@ -2511,6 +2538,8 @@ int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long polnid = zone_to_nid(z->zone); break; + /* case MPOL_PREFERRED_MANY: */ + default: BUG(); } @@ -2862,6 +2891,7 @@ static const char * const policy_modes[] = [MPOL_BIND] = "bind", [MPOL_INTERLEAVE] = "interleave", [MPOL_LOCAL] = "local", + [MPOL_PREFERRED_MANY] = "prefer (many)", }; @@ -2941,6 +2971,7 @@ int mpol_parse_str(char *str, struct mempolicy **mpol) if (!nodelist) err = 0; goto out; + case MPOL_PREFERRED_MANY: case MPOL_BIND: /* * Insist on a nodelist @@ -3023,6 +3054,9 @@ void mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol) switch (mode) { case MPOL_DEFAULT: break; + case MPOL_PREFERRED_MANY: + WARN_ON(flags & MPOL_F_LOCAL); + fallthrough; case MPOL_PREFERRED: if (flags & MPOL_F_LOCAL) mode = MPOL_LOCAL; -- 2.29.2
