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e57b9d8c5a
Commit 682a3385e7 ("mm, page_alloc: inline the fast path of the
zonelist iterator") changed how next_zones_zonelist() is called, by
adding a static inline function to do the fast path. This function
adds:
if (likely(!nodes && zonelist_zone_idx(z) <= highest_zoneidx))
return z;
return __next_zones_zonelist(z, highest_zoneidx, nodes);
Where __next_zones_zonelist() is only called when nodes is not NULL or
zonelist_zone_idx(z) is less than highest_zoneidx.
The original next_zone_zonelist() was converted to __next_zones_zonelist()
but it still maintained:
if (likely(nodes == NULL))
Which is now actually a very unlikely, as it is only called with nodes
equal to NULL when zonelist_zone_idx(z) is greater than highest_zoneidx.
Before this commit, this if had this statistic:
correct incorrect % Function File Line
------- --------- - -------- ---- ----
837895 446078 34 next_zones_zonelist mmzone.c 63
After this commit, it has:
correct incorrect % Function File Line
------- --------- - -------- ---- ----
10 173840 99 __next_zones_zonelist mmzone.c 63
Thus, the if statement is now much more unlikely than it ever was as a
likely.
Link: http://lkml.kernel.org/r/20170105200102.77989567@gandalf.local.home
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
115 lines
2.4 KiB
C
115 lines
2.4 KiB
C
/*
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* linux/mm/mmzone.c
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*
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* management codes for pgdats, zones and page flags
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*/
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#include <linux/stddef.h>
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#include <linux/mm.h>
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#include <linux/mmzone.h>
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struct pglist_data *first_online_pgdat(void)
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{
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return NODE_DATA(first_online_node);
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}
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struct pglist_data *next_online_pgdat(struct pglist_data *pgdat)
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{
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int nid = next_online_node(pgdat->node_id);
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if (nid == MAX_NUMNODES)
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return NULL;
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return NODE_DATA(nid);
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}
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/*
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* next_zone - helper magic for for_each_zone()
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*/
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struct zone *next_zone(struct zone *zone)
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{
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pg_data_t *pgdat = zone->zone_pgdat;
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if (zone < pgdat->node_zones + MAX_NR_ZONES - 1)
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zone++;
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else {
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pgdat = next_online_pgdat(pgdat);
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if (pgdat)
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zone = pgdat->node_zones;
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else
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zone = NULL;
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}
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return zone;
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}
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static inline int zref_in_nodemask(struct zoneref *zref, nodemask_t *nodes)
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{
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#ifdef CONFIG_NUMA
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return node_isset(zonelist_node_idx(zref), *nodes);
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#else
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return 1;
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#endif /* CONFIG_NUMA */
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}
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/* Returns the next zone at or below highest_zoneidx in a zonelist */
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struct zoneref *__next_zones_zonelist(struct zoneref *z,
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enum zone_type highest_zoneidx,
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nodemask_t *nodes)
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{
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/*
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* Find the next suitable zone to use for the allocation.
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* Only filter based on nodemask if it's set
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*/
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if (unlikely(nodes == NULL))
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while (zonelist_zone_idx(z) > highest_zoneidx)
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z++;
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else
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while (zonelist_zone_idx(z) > highest_zoneidx ||
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(z->zone && !zref_in_nodemask(z, nodes)))
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z++;
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return z;
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}
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#ifdef CONFIG_ARCH_HAS_HOLES_MEMORYMODEL
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bool memmap_valid_within(unsigned long pfn,
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struct page *page, struct zone *zone)
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{
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if (page_to_pfn(page) != pfn)
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return false;
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if (page_zone(page) != zone)
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return false;
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return true;
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}
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#endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */
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void lruvec_init(struct lruvec *lruvec)
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{
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enum lru_list lru;
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memset(lruvec, 0, sizeof(struct lruvec));
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for_each_lru(lru)
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INIT_LIST_HEAD(&lruvec->lists[lru]);
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}
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#if defined(CONFIG_NUMA_BALANCING) && !defined(LAST_CPUPID_NOT_IN_PAGE_FLAGS)
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int page_cpupid_xchg_last(struct page *page, int cpupid)
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{
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unsigned long old_flags, flags;
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int last_cpupid;
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do {
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old_flags = flags = page->flags;
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last_cpupid = page_cpupid_last(page);
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flags &= ~(LAST_CPUPID_MASK << LAST_CPUPID_PGSHIFT);
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flags |= (cpupid & LAST_CPUPID_MASK) << LAST_CPUPID_PGSHIFT;
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} while (unlikely(cmpxchg(&page->flags, old_flags, flags) != old_flags));
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return last_cpupid;
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}
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#endif
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