mm/mempolicy: use unified 'nodes' for bind/interleave/prefer policies

Current structure 'mempolicy' uses a union to store the node info for
bind/interleave/perfer policies.

	union {
		short 		 preferred_node; /* preferred */
		nodemask_t	 nodes;		/* interleave/bind */
		/* undefined for default */
	} v;

Since preferred node can also be represented by a nodemask_t with only ont
bit set, unify these policies with using one nodemask_t 'nodes', which can
remove a union, simplify the code and make it easier to support future's
new policy's node info.

Link: https://lore.kernel.org/r/20200630212517.308045-7-ben.widawsky@intel.com
Link: https://lkml.kernel.org/r/1623399825-75651-1-git-send-email-feng.tang@intel.com
Co-developed-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Feng Tang <feng.tang@intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h
index 8773c55..0aaf91b 100644 (file)
--- a/include/linux/mempolicy.h
+++ b/include/linux/mempolicy.h
@@ -46,11 +46,8 @@ struct mempolicy {
        atomic_t refcnt;
        unsigned short mode;    /* See MPOL_* above */
        unsigned short flags;   /* See set_mempolicy() MPOL_F_* above */
-       union {
-               short            preferred_node; /* preferred */
-               nodemask_t       nodes;         /* interleave/bind */
-               /* undefined for default */
-       } v;
+       nodemask_t nodes;       /* interleave/bind/perfer */
+
        union {
                nodemask_t cpuset_mems_allowed; /* relative to these nodes */
                nodemask_t user_nodemask;       /* nodemask passed by user */

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 8739bfd..e32360e 100644 (file)
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -193,7 +193,7 @@ static int mpol_new_interleave(struct mempolicy *pol, const nodemask_t *nodes)
 {
        if (nodes_empty(*nodes))
                return -EINVAL;
-       pol->v.nodes = *nodes;
+       pol->nodes = *nodes;
        return 0;
 }
 
@@ -201,7 +201,9 @@ static int mpol_new_preferred(struct mempolicy *pol, const nodemask_t *nodes)
 {
        if (nodes_empty(*nodes))
                return -EINVAL;
-       pol->v.preferred_node = first_node(*nodes);
+
+       nodes_clear(pol->nodes);
+       node_set(first_node(*nodes), pol->nodes);
        return 0;
 }
 
@@ -209,7 +211,7 @@ static int mpol_new_bind(struct mempolicy *pol, const nodemask_t *nodes)
 {
        if (nodes_empty(*nodes))
                return -EINVAL;
-       pol->v.nodes = *nodes;
+       pol->nodes = *nodes;
        return 0;
 }
 
@@ -324,7 +326,7 @@ static void mpol_rebind_nodemask(struct mempolicy *pol, const nodemask_t *nodes)
        else if (pol->flags & MPOL_F_RELATIVE_NODES)
                mpol_relative_nodemask(&tmp, &pol->w.user_nodemask, nodes);
        else {
-               nodes_remap(tmp, pol->v.nodes, pol->w.cpuset_mems_allowed,
+               nodes_remap(tmp, pol->nodes, pol->w.cpuset_mems_allowed,
                                                                *nodes);
                pol->w.cpuset_mems_allowed = *nodes;
        }
@@ -332,7 +334,7 @@ static void mpol_rebind_nodemask(struct mempolicy *pol, const nodemask_t *nodes)
        if (nodes_empty(tmp))
                tmp = *nodes;
 
-       pol->v.nodes = tmp;
+       pol->nodes = tmp;
 }
 
 static void mpol_rebind_preferred(struct mempolicy *pol,
@@ -897,15 +899,12 @@ static void get_policy_nodemask(struct mempolicy *p, nodemask_t *nodes)
        switch (p->mode) {
        case MPOL_BIND:
        case MPOL_INTERLEAVE:
-               *nodes = p->v.nodes;
+       case MPOL_PREFERRED:
+               *nodes = p->nodes;
                break;
        case MPOL_LOCAL:
                /* return empty node mask for local allocation */
                break;
-
-       case MPOL_PREFERRED:
-               node_set(p->v.preferred_node, *nodes);
-               break;
        default:
                BUG();
        }
@@ -989,7 +988,7 @@ static long do_get_mempolicy(int *policy, nodemask_t *nmask,
                        *policy = err;
                } else if (pol == current->mempolicy &&
                                pol->mode == MPOL_INTERLEAVE) {
-                       *policy = next_node_in(current->il_prev, pol->v.nodes);
+                       *policy = next_node_in(current->il_prev, pol->nodes);
                } else {
                        err = -EINVAL;
                        goto out;
@@ -1857,14 +1856,14 @@ static int apply_policy_zone(struct mempolicy *policy, enum zone_type zone)
        BUG_ON(dynamic_policy_zone == ZONE_MOVABLE);
 
        /*
-        * if policy->v.nodes has movable memory only,
+        * if policy->nodes has movable memory only,
         * we apply policy when gfp_zone(gfp) = ZONE_MOVABLE only.
         *
-        * policy->v.nodes is intersect with node_states[N_MEMORY].
+        * policy->nodes is intersect with node_states[N_MEMORY].
         * so if the following test fails, it implies
-        * policy->v.nodes has movable memory only.
+        * policy->nodes has movable memory only.
         */
-       if (!nodes_intersects(policy->v.nodes, node_states[N_HIGH_MEMORY]))
+       if (!nodes_intersects(policy->nodes, node_states[N_HIGH_MEMORY]))
                dynamic_policy_zone = ZONE_MOVABLE;
 
        return zone >= dynamic_policy_zone;
@@ -1879,8 +1878,8 @@ nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *policy)
        /* Lower zones don't get a nodemask applied for MPOL_BIND */
        if (unlikely(policy->mode == MPOL_BIND) &&
                        apply_policy_zone(policy, gfp_zone(gfp)) &&
-                       cpuset_nodemask_valid_mems_allowed(&policy->v.nodes))
-               return &policy->v.nodes;
+                       cpuset_nodemask_valid_mems_allowed(&policy->nodes))
+               return &policy->nodes;
 
        return NULL;
 }
@@ -1889,7 +1888,7 @@ nodemask_t *policy_nodemask(gfp_t gfp, struct mempolicy *policy)
 static int policy_node(gfp_t gfp, struct mempolicy *policy, int nd)
 {
        if (policy->mode == MPOL_PREFERRED) {
-               nd = policy->v.preferred_node;
+               nd = first_node(policy->nodes);
        } else {
                /*
                 * __GFP_THISNODE shouldn't even be used with the bind policy
@@ -1908,7 +1907,7 @@ static unsigned interleave_nodes(struct mempolicy *policy)
        unsigned next;
        struct task_struct *me = current;
 
-       next = next_node_in(me->il_prev, policy->v.nodes);
+       next = next_node_in(me->il_prev, policy->nodes);
        if (next < MAX_NUMNODES)
                me->il_prev = next;
        return next;
@@ -1932,7 +1931,7 @@ unsigned int mempolicy_slab_node(void)
 
        switch (policy->mode) {
        case MPOL_PREFERRED:
-               return policy->v.preferred_node;
+               return first_node(policy->nodes);
 
        case MPOL_INTERLEAVE:
                return interleave_nodes(policy);
@@ -1948,7 +1947,7 @@ unsigned int mempolicy_slab_node(void)
                enum zone_type highest_zoneidx = gfp_zone(GFP_KERNEL);
                zonelist = &NODE_DATA(node)->node_zonelists[ZONELIST_FALLBACK];
                z = first_zones_zonelist(zonelist, highest_zoneidx,
-                                                       &policy->v.nodes);
+                                                       &policy->nodes);
                return z->zone ? zone_to_nid(z->zone) : node;
        }
        case MPOL_LOCAL:
@@ -1961,12 +1960,12 @@ unsigned int mempolicy_slab_node(void)
 
 /*
  * Do static interleaving for a VMA with known offset @n.  Returns the n'th
- * node in pol->v.nodes (starting from n=0), wrapping around if n exceeds the
+ * node in pol->nodes (starting from n=0), wrapping around if n exceeds the
  * number of present nodes.
  */
 static unsigned offset_il_node(struct mempolicy *pol, unsigned long n)
 {
-       unsigned nnodes = nodes_weight(pol->v.nodes);
+       unsigned nnodes = nodes_weight(pol->nodes);
        unsigned target;
        int i;
        int nid;
@@ -1974,9 +1973,9 @@ static unsigned offset_il_node(struct mempolicy *pol, unsigned long n)
        if (!nnodes)
                return numa_node_id();
        target = (unsigned int)n % nnodes;
-       nid = first_node(pol->v.nodes);
+       nid = first_node(pol->nodes);
        for (i = 0; i < target; i++)
-               nid = next_node(nid, pol->v.nodes);
+               nid = next_node(nid, pol->nodes);
        return nid;
 }
 
@@ -2032,7 +2031,7 @@ int huge_node(struct vm_area_struct *vma, unsigned long addr, gfp_t gfp_flags,
        } else {
                nid = policy_node(gfp_flags, *mpol, numa_node_id());
                if ((*mpol)->mode == MPOL_BIND)
-                       *nodemask = &(*mpol)->v.nodes;
+                       *nodemask = &(*mpol)->nodes;
        }
        return nid;
 }
@@ -2056,7 +2055,6 @@ int huge_node(struct vm_area_struct *vma, unsigned long addr, gfp_t gfp_flags,
 bool init_nodemask_of_mempolicy(nodemask_t *mask)
 {
        struct mempolicy *mempolicy;
-       int nid;
 
        if (!(mask && current->mempolicy))
                return false;
@@ -2065,18 +2063,13 @@ bool init_nodemask_of_mempolicy(nodemask_t *mask)
        mempolicy = current->mempolicy;
        switch (mempolicy->mode) {
        case MPOL_PREFERRED:
-               nid = mempolicy->v.preferred_node;
-               init_nodemask_of_node(mask, nid);
-               break;
-
        case MPOL_BIND:
        case MPOL_INTERLEAVE:
-               *mask = mempolicy->v.nodes;
+               *mask = mempolicy->nodes;
                break;
 
        case MPOL_LOCAL:
-               nid = numa_node_id();
-               init_nodemask_of_node(mask, nid);
+               init_nodemask_of_node(mask, numa_node_id());
                break;
 
        default:
@@ -2110,7 +2103,7 @@ bool mempolicy_in_oom_domain(struct task_struct *tsk,
        task_lock(tsk);
        mempolicy = tsk->mempolicy;
        if (mempolicy && mempolicy->mode == MPOL_BIND)
-               ret = nodes_intersects(mempolicy->v.nodes, *mask);
+               ret = nodes_intersects(mempolicy->nodes, *mask);
        task_unlock(tsk);
 
        return ret;
@@ -2184,7 +2177,7 @@ struct page *alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma,
                 * node in its nodemask, we allocate the standard way.
                 */
                if (pol->mode == MPOL_PREFERRED)
-                       hpage_node = pol->v.preferred_node;
+                       hpage_node = first_node(pol->nodes);
 
                nmask = policy_nodemask(gfp, pol);
                if (!nmask || node_isset(hpage_node, *nmask)) {
@@ -2317,9 +2310,8 @@ bool __mpol_equal(struct mempolicy *a, struct mempolicy *b)
        switch (a->mode) {
        case MPOL_BIND:
        case MPOL_INTERLEAVE:
-               return !!nodes_equal(a->v.nodes, b->v.nodes);
        case MPOL_PREFERRED:
-               return a->v.preferred_node == b->v.preferred_node;
+               return !!nodes_equal(a->nodes, b->nodes);
        case MPOL_LOCAL:
                return true;
        default:
@@ -2459,7 +2451,7 @@ int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long
                break;
 
        case MPOL_PREFERRED:
-               polnid = pol->v.preferred_node;
+               polnid = first_node(pol->nodes);
                break;
 
        case MPOL_LOCAL:
@@ -2469,7 +2461,7 @@ int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long
        case MPOL_BIND:
                /* Optimize placement among multiple nodes via NUMA balancing */
                if (pol->flags & MPOL_F_MORON) {
-                       if (node_isset(thisnid, pol->v.nodes))
+                       if (node_isset(thisnid, pol->nodes))
                                break;
                        goto out;
                }
@@ -2480,12 +2472,12 @@ int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long
                 * else select nearest allowed node, if any.
                 * If no allowed nodes, use current [!misplaced].
                 */
-               if (node_isset(curnid, pol->v.nodes))
+               if (node_isset(curnid, pol->nodes))
                        goto out;
                z = first_zones_zonelist(
                                node_zonelist(numa_node_id(), GFP_HIGHUSER),
                                gfp_zone(GFP_HIGHUSER),
-                               &pol->v.nodes);
+                               &pol->nodes);
                polnid = zone_to_nid(z->zone);
                break;
 
@@ -2688,7 +2680,7 @@ int mpol_set_shared_policy(struct shared_policy *info,
                 vma->vm_pgoff,
                 sz, npol ? npol->mode : -1,
                 npol ? npol->flags : -1,
-                npol ? nodes_addr(npol->v.nodes)[0] : NUMA_NO_NODE);
+                npol ? nodes_addr(npol->nodes)[0] : NUMA_NO_NODE);
 
        if (npol) {
                new = sp_alloc(vma->vm_pgoff, vma->vm_pgoff + sz, npol);
@@ -2786,7 +2778,7 @@ void __init numa_policy_init(void)
                        .refcnt = ATOMIC_INIT(1),
                        .mode = MPOL_PREFERRED,
                        .flags = MPOL_F_MOF | MPOL_F_MORON,
-                       .v = { .preferred_node = nid, },
+                       .nodes = nodemask_of_node(nid),
                };
        }
 
@@ -2945,12 +2937,14 @@ int mpol_parse_str(char *str, struct mempolicy **mpol)
         * Save nodes for mpol_to_str() to show the tmpfs mount options
         * for /proc/mounts, /proc/pid/mounts and /proc/pid/mountinfo.
         */
-       if (mode != MPOL_PREFERRED)
-               new->v.nodes = nodes;
-       else if (nodelist)
-               new->v.preferred_node = first_node(nodes);
-       else
+       if (mode != MPOL_PREFERRED) {
+               new->nodes = nodes;
+       } else if (nodelist) {
+               nodes_clear(new->nodes);
+               node_set(first_node(nodes), new->nodes);
+       } else {
                new->mode = MPOL_LOCAL;
+       }
 
        /*
         * Save nodes for contextualization: this will be used to "clone"
@@ -2999,11 +2993,9 @@ void mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol)
        case MPOL_LOCAL:
                break;
        case MPOL_PREFERRED:
-               node_set(pol->v.preferred_node, nodes);
-               break;
        case MPOL_BIND:
        case MPOL_INTERLEAVE:
-               nodes = pol->v.nodes;
+               nodes = pol->nodes;
                break;
        default:
                WARN_ON_ONCE(1);