mm, page_alloc: avoid looking up the first zone in a zonelist twice
The allocator fast path looks up the first usable zone in a zonelist and
then get_page_from_freelist does the same job in the zonelist iterator.
This patch preserves the necessary information.
4.6.0-rc2 4.6.0-rc2
fastmark-v1r20 initonce-v1r20
Min alloc-odr0-1 364.00 ( 0.00%) 359.00 ( 1.37%)
Min alloc-odr0-2 262.00 ( 0.00%) 260.00 ( 0.76%)
Min alloc-odr0-4 214.00 ( 0.00%) 214.00 ( 0.00%)
Min alloc-odr0-8 186.00 ( 0.00%) 186.00 ( 0.00%)
Min alloc-odr0-16 173.00 ( 0.00%) 173.00 ( 0.00%)
Min alloc-odr0-32 165.00 ( 0.00%) 165.00 ( 0.00%)
Min alloc-odr0-64 161.00 ( 0.00%) 162.00 ( -0.62%)
Min alloc-odr0-128 159.00 ( 0.00%) 161.00 ( -1.26%)
Min alloc-odr0-256 168.00 ( 0.00%) 170.00 ( -1.19%)
Min alloc-odr0-512 180.00 ( 0.00%) 181.00 ( -0.56%)
Min alloc-odr0-1024 190.00 ( 0.00%) 190.00 ( 0.00%)
Min alloc-odr0-2048 196.00 ( 0.00%) 196.00 ( 0.00%)
Min alloc-odr0-4096 202.00 ( 0.00%) 202.00 ( 0.00%)
Min alloc-odr0-8192 206.00 ( 0.00%) 205.00 ( 0.49%)
Min alloc-odr0-16384 206.00 ( 0.00%) 205.00 ( 0.49%)
The benefit is negligible and the results are within the noise but each
cycle counts.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Mel Gorman
Linus Torvalds
parent
48ee5f3696
commit
c33d6c06f6
10
fs/buffer.c
10
fs/buffer.c
@ -255,17 +255,17 @@ out:
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*/
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static void free_more_memory(void)
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{
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struct zone *zone;
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struct zoneref *z;
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int nid;
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wakeup_flusher_threads(1024, WB_REASON_FREE_MORE_MEM);
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yield();
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for_each_online_node(nid) {
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(void)first_zones_zonelist(node_zonelist(nid, GFP_NOFS),
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gfp_zone(GFP_NOFS), NULL,
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&zone);
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if (zone)
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z = first_zones_zonelist(node_zonelist(nid, GFP_NOFS),
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gfp_zone(GFP_NOFS), NULL);
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if (z->zone)
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try_to_free_pages(node_zonelist(nid, GFP_NOFS), 0,
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GFP_NOFS, NULL);
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}
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@ -959,13 +959,10 @@ static __always_inline struct zoneref *next_zones_zonelist(struct zoneref *z,
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*/
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static inline struct zoneref *first_zones_zonelist(struct zonelist *zonelist,
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enum zone_type highest_zoneidx,
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nodemask_t *nodes,
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struct zone **zone)
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nodemask_t *nodes)
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{
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struct zoneref *z = next_zones_zonelist(zonelist->_zonerefs,
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return next_zones_zonelist(zonelist->_zonerefs,
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highest_zoneidx, nodes);
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*zone = zonelist_zone(z);
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return z;
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}
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/**
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@ -980,10 +977,17 @@ static inline struct zoneref *first_zones_zonelist(struct zonelist *zonelist,
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* within a given nodemask
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*/
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#define for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, nodemask) \
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for (z = first_zones_zonelist(zlist, highidx, nodemask, &zone); \
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for (z = first_zones_zonelist(zlist, highidx, nodemask), zone = zonelist_zone(z); \
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zone; \
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z = next_zones_zonelist(++z, highidx, nodemask), \
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zone = zonelist_zone(z)) \
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zone = zonelist_zone(z))
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#define for_next_zone_zonelist_nodemask(zone, z, zlist, highidx, nodemask) \
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for (zone = z->zone; \
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zone; \
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z = next_zones_zonelist(++z, highidx, nodemask), \
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zone = zonelist_zone(z))
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/**
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* for_each_zone_zonelist - helper macro to iterate over valid zones in a zonelist at or below a given zone index
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@ -102,7 +102,7 @@ extern pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address);
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struct alloc_context {
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struct zonelist *zonelist;
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nodemask_t *nodemask;
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struct zone *preferred_zone;
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struct zoneref *preferred_zoneref;
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int classzone_idx;
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int migratetype;
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enum zone_type high_zoneidx;
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@ -1739,18 +1739,18 @@ unsigned int mempolicy_slab_node(void)
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return interleave_nodes(policy);
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case MPOL_BIND: {
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struct zoneref *z;
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/*
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* Follow bind policy behavior and start allocation at the
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* first node.
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*/
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struct zonelist *zonelist;
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struct zone *zone;
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enum zone_type highest_zoneidx = gfp_zone(GFP_KERNEL);
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zonelist = &NODE_DATA(node)->node_zonelists[0];
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(void)first_zones_zonelist(zonelist, highest_zoneidx,
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&policy->v.nodes,
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&zone);
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return zone ? zone->node : node;
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z = first_zones_zonelist(zonelist, highest_zoneidx,
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&policy->v.nodes);
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return z->zone ? z->zone->node : node;
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}
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default:
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@ -2266,7 +2266,7 @@ static void sp_free(struct sp_node *n)
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int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long addr)
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{
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struct mempolicy *pol;
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struct zone *zone;
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struct zoneref *z;
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int curnid = page_to_nid(page);
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unsigned long pgoff;
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int thiscpu = raw_smp_processor_id();
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@ -2298,6 +2298,7 @@ int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long
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break;
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case MPOL_BIND:
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/*
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* allows binding to multiple nodes.
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* use current page if in policy nodemask,
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@ -2306,11 +2307,11 @@ int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long
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*/
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if (node_isset(curnid, pol->v.nodes))
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goto out;
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(void)first_zones_zonelist(
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z = first_zones_zonelist(
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node_zonelist(numa_node_id(), GFP_HIGHUSER),
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gfp_zone(GFP_HIGHUSER),
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&pol->v.nodes, &zone);
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polnid = zone->node;
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&pol->v.nodes);
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polnid = z->zone->node;
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break;
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default:
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@ -2704,7 +2704,7 @@ static struct page *
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get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags,
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const struct alloc_context *ac)
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{
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struct zoneref *z;
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struct zoneref *z = ac->preferred_zoneref;
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struct zone *zone;
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bool fair_skipped = false;
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bool apply_fair = (alloc_flags & ALLOC_FAIR);
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@ -2714,7 +2714,7 @@ zonelist_scan:
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* Scan zonelist, looking for a zone with enough free.
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* See also __cpuset_node_allowed() comment in kernel/cpuset.c.
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*/
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for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->high_zoneidx,
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for_next_zone_zonelist_nodemask(zone, z, ac->zonelist, ac->high_zoneidx,
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ac->nodemask) {
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struct page *page;
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unsigned long mark;
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@ -2734,7 +2734,7 @@ zonelist_scan:
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fair_skipped = true;
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continue;
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}
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if (!zone_local(ac->preferred_zone, zone)) {
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if (!zone_local(ac->preferred_zoneref->zone, zone)) {
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if (fair_skipped)
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goto reset_fair;
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apply_fair = false;
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@ -2780,7 +2780,7 @@ zonelist_scan:
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goto try_this_zone;
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if (zone_reclaim_mode == 0 ||
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!zone_allows_reclaim(ac->preferred_zone, zone))
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!zone_allows_reclaim(ac->preferred_zoneref->zone, zone))
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continue;
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ret = zone_reclaim(zone, gfp_mask, order);
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@ -2802,7 +2802,7 @@ zonelist_scan:
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}
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try_this_zone:
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page = buffered_rmqueue(ac->preferred_zone, zone, order,
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page = buffered_rmqueue(ac->preferred_zoneref->zone, zone, order,
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gfp_mask, alloc_flags, ac->migratetype);
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if (page) {
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if (prep_new_page(page, order, gfp_mask, alloc_flags))
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@ -2831,7 +2831,7 @@ try_this_zone:
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reset_fair:
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apply_fair = false;
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fair_skipped = false;
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reset_alloc_batches(ac->preferred_zone);
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reset_alloc_batches(ac->preferred_zoneref->zone);
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goto zonelist_scan;
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}
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@ -3114,7 +3114,7 @@ static void wake_all_kswapds(unsigned int order, const struct alloc_context *ac)
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for_each_zone_zonelist_nodemask(zone, z, ac->zonelist,
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ac->high_zoneidx, ac->nodemask)
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wakeup_kswapd(zone, order, zone_idx(ac->preferred_zone));
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wakeup_kswapd(zone, order, zonelist_zone_idx(ac->preferred_zoneref));
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}
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static inline unsigned int
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@ -3332,7 +3332,7 @@ retry:
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if ((did_some_progress && order <= PAGE_ALLOC_COSTLY_ORDER) ||
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((gfp_mask & __GFP_REPEAT) && pages_reclaimed < (1 << order))) {
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/* Wait for some write requests to complete then retry */
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wait_iff_congested(ac->preferred_zone, BLK_RW_ASYNC, HZ/50);
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wait_iff_congested(ac->preferred_zoneref->zone, BLK_RW_ASYNC, HZ/50);
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goto retry;
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}
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@ -3370,7 +3370,6 @@ struct page *
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__alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
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struct zonelist *zonelist, nodemask_t *nodemask)
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{
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struct zoneref *preferred_zoneref;
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struct page *page;
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unsigned int cpuset_mems_cookie;
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unsigned int alloc_flags = ALLOC_WMARK_LOW|ALLOC_FAIR;
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@ -3416,14 +3415,14 @@ retry_cpuset:
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ac.spread_dirty_pages = (gfp_mask & __GFP_WRITE);
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/* The preferred zone is used for statistics later */
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preferred_zoneref = first_zones_zonelist(ac.zonelist, ac.high_zoneidx,
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ac.nodemask, &ac.preferred_zone);
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if (!ac.preferred_zone) {
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ac.preferred_zoneref = first_zones_zonelist(ac.zonelist,
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ac.high_zoneidx, ac.nodemask);
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if (!ac.preferred_zoneref) {
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page = NULL;
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goto no_zone;
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}
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ac.classzone_idx = zonelist_zone_idx(preferred_zoneref);
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ac.classzone_idx = zonelist_zone_idx(ac.preferred_zoneref);
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/* First allocation attempt */
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page = get_page_from_freelist(alloc_mask, order, alloc_flags, &ac);
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@ -4462,13 +4461,12 @@ static void build_zonelists(pg_data_t *pgdat)
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*/
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int local_memory_node(int node)
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{
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struct zone *zone;
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struct zoneref *z;
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(void)first_zones_zonelist(node_zonelist(node, GFP_KERNEL),
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z = first_zones_zonelist(node_zonelist(node, GFP_KERNEL),
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gfp_zone(GFP_KERNEL),
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NULL,
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&zone);
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return zone->node;
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NULL);
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return z->zone->node;
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}
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#endif
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