diff options
| -rw-r--r-- | include/linux/mmzone.h | 74 | ||||
| -rw-r--r-- | mm/page_alloc.c | 212 |
2 files changed, 0 insertions, 286 deletions
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 38bed71..1e88aae 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -589,75 +589,8 @@ static inline bool zone_is_empty(struct zone *zone) * [1] : No fallback (__GFP_THISNODE) */ #define MAX_ZONELISTS 2 - - -/* - * We cache key information from each zonelist for smaller cache - * footprint when scanning for free pages in get_page_from_freelist(). - * - * 1) The BITMAP fullzones tracks which zones in a zonelist have come - * up short of free memory since the last time (last_fullzone_zap) - * we zero'd fullzones. - * 2) The array z_to_n[] maps each zone in the zonelist to its node - * id, so that we can efficiently evaluate whether that node is - * set in the current tasks mems_allowed. - * - * Both fullzones and z_to_n[] are one-to-one with the zonelist, - * indexed by a zones offset in the zonelist zones[] array. - * - * The get_page_from_freelist() routine does two scans. During the - * first scan, we skip zones whose corresponding bit in 'fullzones' - * is set or whose corresponding node in current->mems_allowed (which - * comes from cpusets) is not set. During the second scan, we bypass - * this zonelist_cache, to ensure we look methodically at each zone. - * - * Once per second, we zero out (zap) fullzones, forcing us to - * reconsider nodes that might have regained more free memory. - * The field last_full_zap is the time we last zapped fullzones. - * - * This mechanism reduces the amount of time we waste repeatedly - * reexaming zones for free memory when they just came up low on - * memory momentarilly ago. - * - * The zonelist_cache struct members logically belong in struct - * zonelist. However, the mempolicy zonelists constructed for - * MPOL_BIND are intentionally variable length (and usually much - * shorter). A general purpose mechanism for handling structs with - * multiple variable length members is more mechanism than we want - * here. We resort to some special case hackery instead. - * - * The MPOL_BIND zonelists don't need this zonelist_cache (in good - * part because they are shorter), so we put the fixed length stuff - * at the front of the zonelist struct, ending in a variable length - * zones[], as is needed by MPOL_BIND. - * - * Then we put the optional zonelist cache on the end of the zonelist - * struct. This optional stuff is found by a 'zlcache_ptr' pointer in - * the fixed length portion at the front of the struct. This pointer - * both enables us to find the zonelist cache, and in the case of - * MPOL_BIND zonelists, (which will just set the zlcache_ptr to NULL) - * to know that the zonelist cache is not there. - * - * The end result is that struct zonelists come in two flavors: - * 1) The full, fixed length version, shown below, and - * 2) The custom zonelists for MPOL_BIND. - * The custom MPOL_BIND zonelists have a NULL zlcache_ptr and no zlcache. - * - * Even though there may be multiple CPU cores on a node modifying - * fullzones or last_full_zap in the same zonelist_cache at the same - * time, we don't lock it. This is just hint data - if it is wrong now - * and then, the allocator will still function, perhaps a bit slower. - */ - - -struct zonelist_cache { - unsigned short z_to_n[MAX_ZONES_PER_ZONELIST]; /* zone->nid */ - DECLARE_BITMAP(fullzones, MAX_ZONES_PER_ZONELIST); /* zone full? */ - unsigned long last_full_zap; /* when last zap'd (jiffies) */ -}; #else #define MAX_ZONELISTS 1 -struct zonelist_cache; #endif /* @@ -675,9 +608,6 @@ struct zoneref { * allocation, the other zones are fallback zones, in decreasing * priority. * - * If zlcache_ptr is not NULL, then it is just the address of zlcache, - * as explained above. If zlcache_ptr is NULL, there is no zlcache. - * * * To speed the reading of the zonelist, the zonerefs contain the zone index * of the entry being read. Helper functions to access information given * a struct zoneref are @@ -687,11 +617,7 @@ struct zoneref { * zonelist_node_idx() - Return the index of the node for an entry */ struct zonelist { - struct zonelist_cache *zlcache_ptr; // NULL or &zlcache struct zoneref _zonerefs[MAX_ZONES_PER_ZONELIST + 1]; -#ifdef CONFIG_NUMA - struct zonelist_cache zlcache; // optional ... -#endif }; #ifndef CONFIG_DISCONTIGMEM diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 1b37309..8dc6e3c 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2292,122 +2292,6 @@ bool zone_watermark_ok_safe(struct zone *z, unsigned int order, } #ifdef CONFIG_NUMA -/* - * zlc_setup - Setup for "zonelist cache". Uses cached zone data to - * skip over zones that are not allowed by the cpuset, or that have - * been recently (in last second) found to be nearly full. See further - * comments in mmzone.h. Reduces cache footprint of zonelist scans - * that have to skip over a lot of full or unallowed zones. - * - * If the zonelist cache is present in the passed zonelist, then - * returns a pointer to the allowed node mask (either the current - * tasks mems_allowed, or node_states[N_MEMORY].) - * - * If the zonelist cache is not available for this zonelist, does - * nothing and returns NULL. - * - * If the fullzones BITMAP in the zonelist cache is stale (more than - * a second since last zap'd) then we zap it out (clear its bits.) - * - * We hold off even calling zlc_setup, until after we've checked the - * first zone in the zonelist, on the theory that most allocations will - * be satisfied from that first zone, so best to examine that zone as - * quickly as we can. - */ -static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags) -{ - struct zonelist_cache *zlc; /* cached zonelist speedup info */ - nodemask_t *allowednodes; /* zonelist_cache approximation */ - - zlc = zonelist->zlcache_ptr; - if (!zlc) - return NULL; - - if (time_after(jiffies, zlc->last_full_zap + HZ)) { - bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST); - zlc->last_full_zap = jiffies; - } - - allowednodes = !in_interrupt() && (alloc_flags & ALLOC_CPUSET) ? - &cpuset_current_mems_allowed : - &node_states[N_MEMORY]; - return allowednodes; -} - -/* - * Given 'z' scanning a zonelist, run a couple of quick checks to see - * if it is worth looking at further for free memory: - * 1) Check that the zone isn't thought to be full (doesn't have its - * bit set in the zonelist_cache fullzones BITMAP). - * 2) Check that the zones node (obtained from the zonelist_cache - * z_to_n[] mapping) is allowed in the passed in allowednodes mask. - * Return true (non-zero) if zone is worth looking at further, or - * else return false (zero) if it is not. - * - * This check -ignores- the distinction between various watermarks, - * such as GFP_HIGH, GFP_ATOMIC, PF_MEMALLOC, ... If a zone is - * found to be full for any variation of these watermarks, it will - * be considered full for up to one second by all requests, unless - * we are so low on memory on all allowed nodes that we are forced - * into the second scan of the zonelist. - * - * In the second scan we ignore this zonelist cache and exactly - * apply the watermarks to all zones, even it is slower to do so. - * We are low on memory in the second scan, and should leave no stone - * unturned looking for a free page. - */ -static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zoneref *z, - nodemask_t *allowednodes) -{ - struct zonelist_cache *zlc; /* cached zonelist speedup info */ - int i; /* index of *z in zonelist zones */ - int n; /* node that zone *z is on */ - - zlc = zonelist->zlcache_ptr; - if (!zlc) - return 1; - - i = z - zonelist->_zonerefs; - n = zlc->z_to_n[i]; - - /* This zone is worth trying if it is allowed but not full */ - return node_isset(n, *allowednodes) && !test_bit(i, zlc->fullzones); -} - -/* - * Given 'z' scanning a zonelist, set the corresponding bit in - * zlc->fullzones, so that subsequent attempts to allocate a page - * from that zone don't waste time re-examining it. - */ -static void zlc_mark_zone_full(struct zonelist *zonelist, struct zoneref *z) -{ - struct zonelist_cache *zlc; /* cached zonelist speedup info */ - int i; /* index of *z in zonelist zones */ - - zlc = zonelist->zlcache_ptr; - if (!zlc) - return; - - i = z - zonelist->_zonerefs; - - set_bit(i, zlc->fullzones); -} - -/* - * clear all zones full, called after direct reclaim makes progress so that - * a zone that was recently full is not skipped over for up to a second - */ -static void zlc_clear_zones_full(struct zonelist *zonelist) -{ - struct zonelist_cache *zlc; /* cached zonelist speedup info */ - - zlc = zonelist->zlcache_ptr; - if (!zlc) - return; - - bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST); -} - static bool zone_local(struct zone *local_zone, struct zone *zone) { return local_zone->node == zone->node; @@ -2418,28 +2302,7 @@ static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone) return node_distance(zone_to_nid(local_zone), zone_to_nid(zone)) < RECLAIM_DISTANCE; } - #else /* CONFIG_NUMA */ - -static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags) -{ - return NULL; -} - -static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zoneref *z, - nodemask_t *allowednodes) -{ - return 1; -} - -static void zlc_mark_zone_full(struct zonelist *zonelist, struct zoneref *z) -{ -} - -static void zlc_clear_zones_full(struct zonelist *zonelist) -{ -} - static bool zone_local(struct zone *local_zone, struct zone *zone) { return true; @@ -2449,7 +2312,6 @@ static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone) { return true; } - #endif /* CONFIG_NUMA */ static void reset_alloc_batches(struct zone *preferred_zone) @@ -2476,9 +2338,6 @@ get_page_from_freelist(gfp_t gfp_mask, unsigned int order, int alloc_flags, struct zoneref *z; struct page *page = NULL; struct zone *zone; - nodemask_t *allowednodes = NULL;/* zonelist_cache approximation */ - int zlc_active = 0; /* set if using zonelist_cache */ - int did_zlc_setup = 0; /* just call zlc_setup() one time */ int nr_fair_skipped = 0; bool zonelist_rescan; @@ -2493,9 +2352,6 @@ zonelist_scan: ac->nodemask) { unsigned long mark; - if (IS_ENABLED(CONFIG_NUMA) && zlc_active && - !zlc_zone_worth_trying(zonelist, z, allowednodes)) - continue; if (cpusets_enabled() && (alloc_flags & ALLOC_CPUSET) && !cpuset_zone_allowed(zone, gfp_mask)) @@ -2553,28 +2409,8 @@ zonelist_scan: if (alloc_flags & ALLOC_NO_WATERMARKS) goto try_this_zone; - if (IS_ENABLED(CONFIG_NUMA) && - !did_zlc_setup && nr_online_nodes > 1) { - /* - * we do zlc_setup if there are multiple nodes - * and before considering the first zone allowed - * by the cpuset. - */ - allowednodes = zlc_setup(zonelist, alloc_flags); - zlc_active = 1; - did_zlc_setup = 1; - } - if (zone_reclaim_mode == 0 || !zone_allows_reclaim(ac->preferred_zone, zone)) - goto this_zone_full; - - /* - * As we may have just activated ZLC, check if the first - * eligible zone has failed zone_reclaim recently. - */ - if (IS_ENABLED(CONFIG_NUMA) && zlc_active && - !zlc_zone_worth_trying(zonelist, z, allowednodes)) continue; ret = zone_reclaim(zone, gfp_mask, order); @@ -2591,19 +2427,6 @@ zonelist_scan: ac->classzone_idx, alloc_flags)) goto try_this_zone; - /* - * Failed to reclaim enough to meet watermark. - * Only mark the zone full if checking the min - * watermark or if we failed to reclaim just - * 1<<order pages or else the page allocator - * fastpath will prematurely mark zones full - * when the watermark is between the low and - * min watermarks. - */ - if (((alloc_flags & ALLOC_WMARK_MASK) == ALLOC_WMARK_MIN) || - ret == ZONE_RECLAIM_SOME) - goto this_zone_full; - continue; } } @@ -2616,9 +2439,6 @@ try_this_zone: goto try_this_zone; return page; } -this_zone_full: - if (IS_ENABLED(CONFIG_NUMA) && zlc_active) - zlc_mark_zone_full(zonelist, z); } /* @@ -2639,12 +2459,6 @@ this_zone_full: zonelist_rescan = true; } - if (unlikely(IS_ENABLED(CONFIG_NUMA) && zlc_active)) { - /* Disable zlc cache for second zonelist scan */ - zlc_active = 0; - zonelist_rescan = true; - } - if (zonelist_rescan) goto zonelist_scan; @@ -2889,10 +2703,6 @@ __alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order, if (unlikely(!(*did_some_progress))) return NULL; - /* After successful reclaim, reconsider all zones for allocation */ - if (IS_ENABLED(CONFIG_NUMA)) - zlc_clear_zones_full(ac->zonelist); - retry: page = get_page_from_freelist(gfp_mask, order, alloc_flags & ~ALLOC_NO_WATERMARKS, ac); @@ -4228,20 +4038,6 @@ static void build_zonelists(pg_data_t *pgdat) build_thisnode_zonelists(pgdat); } -/* Construct the zonelist performance cache - see further mmzone.h */ -static void build_zonelist_cache(pg_data_t *pgdat) -{ - struct zonelist *zonelist; - struct zonelist_cache *zlc; - struct zoneref *z; - - zonelist = &pgdat->node_zonelists[0]; - zonelist->zlcache_ptr = zlc = &zonelist->zlcache; - bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST); - for (z = zonelist->_zonerefs; z->zone; z++) - zlc->z_to_n[z - zonelist->_zonerefs] = zonelist_node_idx(z); -} - #ifdef CONFIG_HAVE_MEMORYLESS_NODES /* * Return node id of node used for "local" allocations. @@ -4302,12 +4098,6 @@ static void build_zonelists(pg_data_t *pgdat) zonelist->_zonerefs[j].zone_idx = 0; } -/* non-NUMA variant of zonelist performance cache - just NULL zlcache_ptr */ -static void build_zonelist_cache(pg_data_t *pgdat) -{ - pgdat->node_zonelists[0].zlcache_ptr = NULL; -} - #endif /* CONFIG_NUMA */ /* @@ -4348,14 +4138,12 @@ static int __build_all_zonelists(void *data) if (self && !node_online(self->node_id)) { build_zonelists(self); - build_zonelist_cache(self); } for_each_online_node(nid) { pg_data_t *pgdat = NODE_DATA(nid); build_zonelists(pgdat); - build_zonelist_cache(pgdat); } /* |
