Refactor uma_zfree_arg into several functions to make control flow more
clear and icache usage cleaner. Reviewed by: markj Differential Revision: https://reviews.freebsd.org/D22491
This commit is contained in:
Jeff Roberson
parent
1867d2f2e9
commit
0a81b4395e
@ -283,6 +283,7 @@ static int zone_import(uma_zone_t, void **, int, int, int);
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static void zone_release(uma_zone_t, void **, int);
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static void uma_zero_item(void *, uma_zone_t);
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static bool cache_alloc(uma_zone_t, uma_cache_t, void *, int);
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static bool cache_free(uma_zone_t, uma_cache_t, void *, void *, int);
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void uma_print_zone(uma_zone_t);
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void uma_print_stats(void);
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@ -2466,6 +2467,17 @@ bucket_pop(uma_zone_t zone, uma_cache_t cache, uma_bucket_t bucket)
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return (item);
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}
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static inline void
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bucket_push(uma_zone_t zone, uma_cache_t cache, uma_bucket_t bucket,
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void *item)
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{
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KASSERT(bucket->ub_bucket[bucket->ub_cnt] == NULL,
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("uma_zfree: Freeing to non free bucket index."));
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bucket->ub_bucket[bucket->ub_cnt] = item;
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bucket->ub_cnt++;
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cache->uc_frees++;
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}
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static void *
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item_ctor(uma_zone_t zone, void *udata, int flags, void *item)
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{
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@ -3158,12 +3170,7 @@ uma_zfree_arg(uma_zone_t zone, void *item, void *udata)
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{
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uma_cache_t cache;
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uma_bucket_t bucket;
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uma_zone_domain_t zdom;
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int cpu, domain;
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#ifdef UMA_XDOMAIN
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int itemdomain;
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#endif
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bool lockfail;
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int cpu, domain, itemdomain;
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/* Enable entropy collection for RANDOM_ENABLE_UMA kernel option */
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random_harvest_fast_uma(&zone, sizeof(zone), RANDOM_UMA);
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@ -3196,11 +3203,6 @@ uma_zfree_arg(uma_zone_t zone, void *item, void *udata)
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if (zone->uz_sleepers > 0)
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goto zfree_item;
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#ifdef UMA_XDOMAIN
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if ((zone->uz_flags & UMA_ZONE_NUMA) != 0)
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itemdomain = _vm_phys_domain(pmap_kextract((vm_offset_t)item));
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#endif
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/*
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* If possible, free to the per-CPU cache. There are two
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* requirements for safe access to the per-CPU cache: (1) the thread
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@ -3212,90 +3214,88 @@ uma_zfree_arg(uma_zone_t zone, void *item, void *udata)
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* current cache; when we re-acquire the critical section, we must
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* detect and handle migration if it has occurred.
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*/
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zfree_restart:
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domain = itemdomain = 0;
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critical_enter();
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do {
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cpu = curcpu;
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cache = &zone->uz_cpu[cpu];
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zfree_start:
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domain = PCPU_GET(domain);
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bucket = cache->uc_allocbucket;
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#ifdef UMA_XDOMAIN
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if ((zone->uz_flags & UMA_ZONE_NUMA) == 0)
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itemdomain = domain;
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if ((zone->uz_flags & UMA_ZONE_NUMA) != 0) {
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itemdomain = _vm_phys_domain(pmap_kextract((vm_offset_t)item));
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domain = PCPU_GET(domain);
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}
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if ((zone->uz_flags & UMA_ZONE_NUMA) != 0 &&
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domain != itemdomain) {
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bucket = cache->uc_crossbucket;
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} else
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#endif
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/*
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* Try to free into the allocbucket first to give LIFO ordering
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* for cache-hot datastructures. Spill over into the freebucket
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* if necessary. Alloc will swap them if one runs dry.
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*/
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#ifdef UMA_XDOMAIN
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if (domain != itemdomain) {
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bucket = cache->uc_crossbucket;
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} else
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#endif
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{
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bucket = cache->uc_allocbucket;
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if (bucket == NULL || bucket->ub_cnt >= bucket->ub_entries)
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bucket = cache->uc_freebucket;
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}
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if (bucket != NULL && bucket->ub_cnt < bucket->ub_entries) {
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KASSERT(bucket->ub_bucket[bucket->ub_cnt] == NULL,
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("uma_zfree: Freeing to non free bucket index."));
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bucket->ub_bucket[bucket->ub_cnt] = item;
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bucket->ub_cnt++;
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cache->uc_frees++;
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if (__predict_true(bucket != NULL &&
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bucket->ub_cnt < bucket->ub_entries)) {
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bucket_push(zone, cache, bucket, item);
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critical_exit();
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return;
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}
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} while (cache_free(zone, cache, udata, item, itemdomain));
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critical_exit();
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/*
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* We must go back the zone, which requires acquiring the zone lock,
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* which in turn means we must release and re-acquire the critical
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* section. Since the critical section is released, we may be
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* preempted or migrate. As such, make sure not to maintain any
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* thread-local state specific to the cache from prior to releasing
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* the critical section.
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* If nothing else caught this, we'll just do an internal free.
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*/
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critical_exit();
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if (zone->uz_count == 0 || bucketdisable)
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goto zfree_item;
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zfree_item:
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zone_free_item(zone, item, udata, SKIP_DTOR);
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}
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lockfail = false;
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static void
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zone_free_bucket(uma_zone_t zone, uma_bucket_t bucket, void *udata,
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int domain, int itemdomain)
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{
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uma_zone_domain_t zdom;
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#ifdef UMA_XDOMAIN
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/*
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* Buckets coming from the wrong domain will be entirely for the
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* only other domain on two domain systems. In this case we can
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* simply cache them. Otherwise we need to sort them back to
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* correct domains by freeing the contents to the slab layer.
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*/
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if (domain != itemdomain && vm_ndomains > 2) {
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CTR3(KTR_UMA,
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"uma_zfree: zone %s(%p) draining cross bucket %p",
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zone->uz_name, zone, bucket);
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bucket_drain(zone, bucket);
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bucket_free(zone, bucket, udata);
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return;
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}
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#endif
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/*
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* Attempt to save the bucket in the zone's domain bucket cache.
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*
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* We bump the uz count when the cache size is insufficient to
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* handle the working set.
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*/
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if (ZONE_TRYLOCK(zone) == 0) {
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/* Record contention to size the buckets. */
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ZONE_LOCK(zone);
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lockfail = true;
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if (zone->uz_count < zone->uz_count_max)
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zone->uz_count++;
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}
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critical_enter();
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cpu = curcpu;
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domain = PCPU_GET(domain);
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cache = &zone->uz_cpu[cpu];
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#ifdef UMA_XDOMAIN
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if (domain != itemdomain)
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bucket = cache->uc_crossbucket;
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else
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#endif
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bucket = cache->uc_freebucket;
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if (bucket != NULL && bucket->ub_cnt < bucket->ub_entries) {
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ZONE_UNLOCK(zone);
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goto zfree_start;
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}
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#ifdef UMA_XDOMAIN
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if (domain != itemdomain)
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cache->uc_crossbucket = NULL;
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else
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#endif
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cache->uc_freebucket = NULL;
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/* We are no longer associated with this CPU. */
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critical_exit();
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#ifdef UMA_XDOMAIN
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if (domain != itemdomain) {
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if (bucket != NULL) {
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zone->uz_xdomain += bucket->ub_cnt;
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if (vm_ndomains > 2 ||
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zone->uz_bkt_count >= zone->uz_bkt_max) {
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CTR3(KTR_UMA,
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"uma_zfree: zone %s(%p) putting bucket %p on free list",
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zone->uz_name, zone, bucket);
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/* ub_cnt is pointing to the last free item */
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KASSERT(bucket->ub_cnt == bucket->ub_entries,
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("uma_zfree: Attempting to insert partial bucket onto the full list.\n"));
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if (zone->uz_bkt_count >= zone->uz_bkt_max) {
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ZONE_UNLOCK(zone);
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bucket_drain(zone, bucket);
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bucket_free(zone, bucket, udata);
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@ -3304,83 +3304,97 @@ uma_zfree_arg(uma_zone_t zone, void *item, void *udata)
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zone_put_bucket(zone, zdom, bucket, true);
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ZONE_UNLOCK(zone);
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}
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} else
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ZONE_UNLOCK(zone);
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bucket = bucket_alloc(zone, udata, M_NOWAIT);
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if (bucket == NULL)
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goto zfree_item;
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critical_enter();
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cpu = curcpu;
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cache = &zone->uz_cpu[cpu];
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if (cache->uc_crossbucket == NULL) {
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cache->uc_crossbucket = bucket;
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goto zfree_start;
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}
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critical_exit();
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bucket_free(zone, bucket, udata);
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goto zfree_restart;
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}
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#endif
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if ((zone->uz_flags & UMA_ZONE_NUMA) != 0) {
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zdom = &zone->uz_domain[domain];
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} else {
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domain = 0;
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zdom = &zone->uz_domain[0];
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}
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/* Can we throw this on the zone full list? */
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if (bucket != NULL) {
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CTR3(KTR_UMA,
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"uma_zfree: zone %s(%p) putting bucket %p on free list",
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zone->uz_name, zone, bucket);
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/* ub_cnt is pointing to the last free item */
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KASSERT(bucket->ub_cnt == bucket->ub_entries,
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("uma_zfree: Attempting to insert not full bucket onto the full list.\n"));
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if (zone->uz_bkt_count >= zone->uz_bkt_max) {
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ZONE_UNLOCK(zone);
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bucket_drain(zone, bucket);
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bucket_free(zone, bucket, udata);
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goto zfree_restart;
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} else
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zone_put_bucket(zone, zdom, bucket, true);
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}
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/*
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* We bump the uz count when the cache size is insufficient to
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* handle the working set.
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* Populate a free or cross bucket for the current cpu cache. Free any
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* existing full bucket either to the zone cache or back to the slab layer.
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*
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* Enters and returns in a critical section. false return indicates that
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* we can not satisfy this free in the cache layer. true indicates that
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* the caller should retry.
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*/
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if (lockfail && zone->uz_count < zone->uz_count_max)
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zone->uz_count++;
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ZONE_UNLOCK(zone);
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static __noinline bool
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cache_free(uma_zone_t zone, uma_cache_t cache, void *udata, void *item,
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int itemdomain)
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{
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uma_bucket_t bucket;
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int cpu, domain;
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CRITICAL_ASSERT(curthread);
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if (zone->uz_count == 0 || bucketdisable)
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return false;
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cpu = curcpu;
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cache = &zone->uz_cpu[cpu];
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/*
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* NUMA domains need to free to the correct zdom. When XDOMAIN
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* is enabled this is the zdom of the item and the bucket may be
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* the cross bucket if they do not match.
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*/
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if ((zone->uz_flags & UMA_ZONE_NUMA) != 0)
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#ifdef UMA_XDOMAIN
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domain = PCPU_GET(domain);
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#else
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itemdomain = domain = PCPU_GET(domain);
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#endif
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else
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itemdomain = domain = 0;
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#ifdef UMA_XDOMAIN
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if (domain != itemdomain) {
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bucket = cache->uc_crossbucket;
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cache->uc_crossbucket = NULL;
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if (bucket != NULL)
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atomic_add_64(&zone->uz_xdomain, bucket->ub_cnt);
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} else
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#endif
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{
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bucket = cache->uc_freebucket;
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cache->uc_freebucket = NULL;
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}
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/* We are no longer associated with this CPU. */
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critical_exit();
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if (bucket != NULL)
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zone_free_bucket(zone, bucket, udata, domain, itemdomain);
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bucket = bucket_alloc(zone, udata, M_NOWAIT);
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CTR3(KTR_UMA, "uma_zfree: zone %s(%p) allocated bucket %p",
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zone->uz_name, zone, bucket);
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if (bucket) {
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critical_enter();
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if (bucket == NULL)
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return (false);
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cpu = curcpu;
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cache = &zone->uz_cpu[cpu];
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if (cache->uc_freebucket == NULL &&
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((zone->uz_flags & UMA_ZONE_NUMA) == 0 ||
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domain == PCPU_GET(domain))) {
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cache->uc_freebucket = bucket;
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goto zfree_start;
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}
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#ifdef UMA_XDOMAIN
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/*
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* We lost the race, start over. We have to drop our
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* critical section to free the bucket.
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* Check to see if we should be populating the cross bucket. If it
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* is already populated we will fall through and attempt to populate
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* the free bucket.
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*/
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if ((zone->uz_flags & UMA_ZONE_NUMA) != 0) {
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domain = PCPU_GET(domain);
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if (domain != itemdomain && cache->uc_crossbucket == NULL) {
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cache->uc_crossbucket = bucket;
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return (true);
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}
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}
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#endif
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/*
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* We may have lost the race to fill the bucket or switched CPUs.
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*/
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if (cache->uc_freebucket != NULL) {
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critical_exit();
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bucket_free(zone, bucket, udata);
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goto zfree_restart;
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}
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critical_enter();
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} else
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cache->uc_freebucket = bucket;
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/*
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* If nothing else caught this, we'll just do an internal free.
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*/
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zfree_item:
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zone_free_item(zone, item, udata, SKIP_DTOR);
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return (true);
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}
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void
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