diff options
Diffstat (limited to 'mm/workingset.c')
| -rw-r--r-- | mm/workingset.c | 170 |
1 files changed, 132 insertions, 38 deletions
diff --git a/mm/workingset.c b/mm/workingset.c index 61ead9e55..8a75f8d29 100644 --- a/mm/workingset.c +++ b/mm/workingset.c @@ -152,8 +152,25 @@ * refault distance will immediately activate the refaulting page. */ -static void *pack_shadow(unsigned long eviction, struct zone *zone) +#define EVICTION_SHIFT (RADIX_TREE_EXCEPTIONAL_ENTRY + \ + ZONES_SHIFT + NODES_SHIFT + \ + MEM_CGROUP_ID_SHIFT) +#define EVICTION_MASK (~0UL >> EVICTION_SHIFT) + +/* + * Eviction timestamps need to be able to cover the full range of + * actionable refaults. However, bits are tight in the radix tree + * entry, and after storing the identifier for the lruvec there might + * not be enough left to represent every single actionable refault. In + * that case, we have to sacrifice granularity for distance, and group + * evictions into coarser buckets by shaving off lower timestamp bits. + */ +static unsigned int bucket_order __read_mostly; + +static void *pack_shadow(int memcgid, struct zone *zone, unsigned long eviction) { + eviction >>= bucket_order; + eviction = (eviction << MEM_CGROUP_ID_SHIFT) | memcgid; eviction = (eviction << NODES_SHIFT) | zone_to_nid(zone); eviction = (eviction << ZONES_SHIFT) | zone_idx(zone); eviction = (eviction << RADIX_TREE_EXCEPTIONAL_SHIFT); @@ -161,45 +178,23 @@ static void *pack_shadow(unsigned long eviction, struct zone *zone) return (void *)(eviction | RADIX_TREE_EXCEPTIONAL_ENTRY); } -static void unpack_shadow(void *shadow, - struct zone **zone, - unsigned long *distance) +static void unpack_shadow(void *shadow, int *memcgidp, struct zone **zonep, + unsigned long *evictionp) { unsigned long entry = (unsigned long)shadow; - unsigned long eviction; - unsigned long refault; - unsigned long mask; - int zid, nid; + int memcgid, nid, zid; entry >>= RADIX_TREE_EXCEPTIONAL_SHIFT; zid = entry & ((1UL << ZONES_SHIFT) - 1); entry >>= ZONES_SHIFT; nid = entry & ((1UL << NODES_SHIFT) - 1); entry >>= NODES_SHIFT; - eviction = entry; + memcgid = entry & ((1UL << MEM_CGROUP_ID_SHIFT) - 1); + entry >>= MEM_CGROUP_ID_SHIFT; - *zone = NODE_DATA(nid)->node_zones + zid; - - refault = atomic_long_read(&(*zone)->inactive_age); - mask = ~0UL >> (NODES_SHIFT + ZONES_SHIFT + - RADIX_TREE_EXCEPTIONAL_SHIFT); - /* - * The unsigned subtraction here gives an accurate distance - * across inactive_age overflows in most cases. - * - * There is a special case: usually, shadow entries have a - * short lifetime and are either refaulted or reclaimed along - * with the inode before they get too old. But it is not - * impossible for the inactive_age to lap a shadow entry in - * the field, which can then can result in a false small - * refault distance, leading to a false activation should this - * old entry actually refault again. However, earlier kernels - * used to deactivate unconditionally with *every* reclaim - * invocation for the longest time, so the occasional - * inappropriate activation leading to pressure on the active - * list is not a problem. - */ - *distance = (refault - eviction) & mask; + *memcgidp = memcgid; + *zonep = NODE_DATA(nid)->node_zones + zid; + *evictionp = entry << bucket_order; } /** @@ -212,11 +207,20 @@ static void unpack_shadow(void *shadow, */ void *workingset_eviction(struct address_space *mapping, struct page *page) { + struct mem_cgroup *memcg = page_memcg(page); struct zone *zone = page_zone(page); + int memcgid = mem_cgroup_id(memcg); unsigned long eviction; + struct lruvec *lruvec; - eviction = atomic_long_inc_return(&zone->inactive_age); - return pack_shadow(eviction, zone); + /* Page is fully exclusive and pins page->mem_cgroup */ + VM_BUG_ON_PAGE(PageLRU(page), page); + VM_BUG_ON_PAGE(page_count(page), page); + VM_BUG_ON_PAGE(!PageLocked(page), page); + + lruvec = mem_cgroup_zone_lruvec(zone, memcg); + eviction = atomic_long_inc_return(&lruvec->inactive_age); + return pack_shadow(memcgid, zone, eviction); } /** @@ -231,12 +235,64 @@ void *workingset_eviction(struct address_space *mapping, struct page *page) bool workingset_refault(void *shadow) { unsigned long refault_distance; + unsigned long active_file; + struct mem_cgroup *memcg; + unsigned long eviction; + struct lruvec *lruvec; + unsigned long refault; struct zone *zone; + int memcgid; + + unpack_shadow(shadow, &memcgid, &zone, &eviction); + + rcu_read_lock(); + /* + * Look up the memcg associated with the stored ID. It might + * have been deleted since the page's eviction. + * + * Note that in rare events the ID could have been recycled + * for a new cgroup that refaults a shared page. This is + * impossible to tell from the available data. However, this + * should be a rare and limited disturbance, and activations + * are always speculative anyway. Ultimately, it's the aging + * algorithm's job to shake out the minimum access frequency + * for the active cache. + * + * XXX: On !CONFIG_MEMCG, this will always return NULL; it + * would be better if the root_mem_cgroup existed in all + * configurations instead. + */ + memcg = mem_cgroup_from_id(memcgid); + if (!mem_cgroup_disabled() && !memcg) { + rcu_read_unlock(); + return false; + } + lruvec = mem_cgroup_zone_lruvec(zone, memcg); + refault = atomic_long_read(&lruvec->inactive_age); + active_file = lruvec_lru_size(lruvec, LRU_ACTIVE_FILE); + rcu_read_unlock(); + + /* + * The unsigned subtraction here gives an accurate distance + * across inactive_age overflows in most cases. + * + * There is a special case: usually, shadow entries have a + * short lifetime and are either refaulted or reclaimed along + * with the inode before they get too old. But it is not + * impossible for the inactive_age to lap a shadow entry in + * the field, which can then can result in a false small + * refault distance, leading to a false activation should this + * old entry actually refault again. However, earlier kernels + * used to deactivate unconditionally with *every* reclaim + * invocation for the longest time, so the occasional + * inappropriate activation leading to pressure on the active + * list is not a problem. + */ + refault_distance = (refault - eviction) & EVICTION_MASK; - unpack_shadow(shadow, &zone, &refault_distance); inc_zone_state(zone, WORKINGSET_REFAULT); - if (refault_distance <= zone_page_state(zone, NR_ACTIVE_FILE)) { + if (refault_distance <= active_file) { inc_zone_state(zone, WORKINGSET_ACTIVATE); return true; } @@ -249,7 +305,22 @@ bool workingset_refault(void *shadow) */ void workingset_activation(struct page *page) { - atomic_long_inc(&page_zone(page)->inactive_age); + struct lruvec *lruvec; + + lock_page_memcg(page); + /* + * Filter non-memcg pages here, e.g. unmap can call + * mark_page_accessed() on VDSO pages. + * + * XXX: See workingset_refault() - this should return + * root_mem_cgroup even for !CONFIG_MEMCG. + */ + if (!mem_cgroup_disabled() && !page_memcg(page)) + goto out; + lruvec = mem_cgroup_zone_lruvec(page_zone(page), page_memcg(page)); + atomic_long_inc(&lruvec->inactive_age); +out: + unlock_page_memcg(page); } /* @@ -278,7 +349,13 @@ static unsigned long count_shadow_nodes(struct shrinker *shrinker, shadow_nodes = list_lru_shrink_count(&workingset_shadow_nodes, sc); local_irq_enable(); - pages = node_present_pages(sc->nid); + if (memcg_kmem_enabled()) + pages = mem_cgroup_node_nr_lru_pages(sc->memcg, sc->nid, + LRU_ALL_FILE); + else + pages = node_page_state(sc->nid, NR_ACTIVE_FILE) + + node_page_state(sc->nid, NR_INACTIVE_FILE); + /* * Active cache pages are limited to 50% of memory, and shadow * entries that represent a refault distance bigger than that @@ -387,7 +464,7 @@ static struct shrinker workingset_shadow_shrinker = { .count_objects = count_shadow_nodes, .scan_objects = scan_shadow_nodes, .seeks = DEFAULT_SEEKS, - .flags = SHRINKER_NUMA_AWARE, + .flags = SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE, }; /* @@ -398,8 +475,25 @@ static struct lock_class_key shadow_nodes_key; static int __init workingset_init(void) { + unsigned int timestamp_bits; + unsigned int max_order; int ret; + BUILD_BUG_ON(BITS_PER_LONG < EVICTION_SHIFT); + /* + * Calculate the eviction bucket size to cover the longest + * actionable refault distance, which is currently half of + * memory (totalram_pages/2). However, memory hotplug may add + * some more pages at runtime, so keep working with up to + * double the initial memory by using totalram_pages as-is. + */ + timestamp_bits = BITS_PER_LONG - EVICTION_SHIFT; + max_order = fls_long(totalram_pages - 1); + if (max_order > timestamp_bits) + bucket_order = max_order - timestamp_bits; + printk("workingset: timestamp_bits=%d max_order=%d bucket_order=%u\n", + timestamp_bits, max_order, bucket_order); + ret = list_lru_init_key(&workingset_shadow_nodes, &shadow_nodes_key); if (ret) goto err; |