.lock = INIT_LOCAL_LOCK(lock),
};
+#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)
+/*
+ * On SMP, spin_trylock is sufficient protection.
+ * On PREEMPT_RT, spin_trylock is equivalent on both SMP and UP.
+ */
+#define pcp_trylock_prepare(flags) do { } while (0)
+#define pcp_trylock_finish(flag) do { } while (0)
+#else
+
+/* UP spin_trylock always succeeds so disable IRQs to prevent re-entrancy. */
+#define pcp_trylock_prepare(flags) local_irq_save(flags)
+#define pcp_trylock_finish(flags) local_irq_restore(flags)
+#endif
+
#ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID
DEFINE_PER_CPU(int, numa_node);
EXPORT_PER_CPU_SYMBOL(numa_node);
*/
void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
{
- unsigned long flags;
int to_drain, batch;
- local_lock_irqsave(&pagesets.lock, flags);
batch = READ_ONCE(pcp->batch);
to_drain = min(pcp->count, batch);
- if (to_drain > 0)
+ if (to_drain > 0) {
+ unsigned long flags;
+
+ /*
+ * free_pcppages_bulk expects IRQs disabled for zone->lock
+ * so even though pcp->lock is not intended to be IRQ-safe,
+ * it's needed in this context.
+ */
+ spin_lock_irqsave(&pcp->lock, flags);
free_pcppages_bulk(zone, to_drain, pcp, 0);
- local_unlock_irqrestore(&pagesets.lock, flags);
+ spin_unlock_irqrestore(&pcp->lock, flags);
+ }
}
#endif
*/
static void drain_pages_zone(unsigned int cpu, struct zone *zone)
{
- unsigned long flags;
struct per_cpu_pages *pcp;
- local_lock_irqsave(&pagesets.lock, flags);
-
pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu);
- if (pcp->count)
- free_pcppages_bulk(zone, pcp->count, pcp, 0);
+ if (pcp->count) {
+ unsigned long flags;
- local_unlock_irqrestore(&pagesets.lock, flags);
+ /* See drain_zone_pages on why this is disabling IRQs */
+ spin_lock_irqsave(&pcp->lock, flags);
+ free_pcppages_bulk(zone, pcp->count, pcp, 0);
+ spin_unlock_irqrestore(&pcp->lock, flags);
+ }
}
/*
return min(READ_ONCE(pcp->batch) << 2, high);
}
-static void free_unref_page_commit(struct page *page, int migratetype,
+static void free_unref_page_commit(struct zone *zone, struct per_cpu_pages *pcp,
+ struct page *page, int migratetype,
unsigned int order)
{
- struct zone *zone = page_zone(page);
- struct per_cpu_pages *pcp;
int high;
int pindex;
bool free_high;
__count_vm_event(PGFREE);
- pcp = this_cpu_ptr(zone->per_cpu_pageset);
pindex = order_to_pindex(migratetype, order);
list_add(&page->pcp_list, &pcp->lists[pindex]);
pcp->count += 1 << order;
void free_unref_page(struct page *page, unsigned int order)
{
unsigned long flags;
+ unsigned long __maybe_unused UP_flags;
+ struct per_cpu_pages *pcp;
+ struct zone *zone;
unsigned long pfn = page_to_pfn(page);
int migratetype;
}
local_lock_irqsave(&pagesets.lock, flags);
- free_unref_page_commit(page, migratetype, order);
+ zone = page_zone(page);
+ pcp_trylock_prepare(UP_flags);
+ pcp = this_cpu_ptr(zone->per_cpu_pageset);
+ if (spin_trylock(&pcp->lock)) {
+ free_unref_page_commit(zone, pcp, page, migratetype, order);
+ spin_unlock(&pcp->lock);
+ } else {
+ free_one_page(zone, page, pfn, order, migratetype, FPI_NONE);
+ }
+ pcp_trylock_finish(UP_flags);
local_unlock_irqrestore(&pagesets.lock, flags);
}
void free_unref_page_list(struct list_head *list)
{
struct page *page, *next;
+ struct per_cpu_pages *pcp = NULL;
+ struct zone *locked_zone = NULL;
unsigned long flags;
int batch_count = 0;
int migratetype;
local_lock_irqsave(&pagesets.lock, flags);
list_for_each_entry_safe(page, next, list, lru) {
+ struct zone *zone = page_zone(page);
+
+ /* Different zone, different pcp lock. */
+ if (zone != locked_zone) {
+ if (pcp)
+ spin_unlock(&pcp->lock);
+ locked_zone = zone;
+ pcp = this_cpu_ptr(zone->per_cpu_pageset);
+ spin_lock(&pcp->lock);
+ }
+
/*
* Non-isolated types over MIGRATE_PCPTYPES get added
* to the MIGRATE_MOVABLE pcp list.
migratetype = MIGRATE_MOVABLE;
trace_mm_page_free_batched(page);
- free_unref_page_commit(page, migratetype, 0);
+ free_unref_page_commit(zone, pcp, page, migratetype, 0);
/*
* Guard against excessive IRQ disabled times when we get
* a large list of pages to free.
*/
if (++batch_count == SWAP_CLUSTER_MAX) {
+ spin_unlock(&pcp->lock);
local_unlock_irqrestore(&pagesets.lock, flags);
batch_count = 0;
local_lock_irqsave(&pagesets.lock, flags);
+ pcp = this_cpu_ptr(locked_zone->per_cpu_pageset);
+ spin_lock(&pcp->lock);
}
}
+
+ if (pcp)
+ spin_unlock(&pcp->lock);
local_unlock_irqrestore(&pagesets.lock, flags);
}
struct list_head *list;
struct page *page;
unsigned long flags;
+ unsigned long __maybe_unused UP_flags;
local_lock_irqsave(&pagesets.lock, flags);
+ /*
+ * spin_trylock may fail due to a parallel drain. In the future, the
+ * trylock will also protect against IRQ reentrancy.
+ */
+ pcp = this_cpu_ptr(zone->per_cpu_pageset);
+ pcp_trylock_prepare(UP_flags);
+ if (!spin_trylock(&pcp->lock)) {
+ pcp_trylock_finish(UP_flags);
+ local_unlock_irqrestore(&pagesets.lock, flags);
+ return NULL;
+ }
+
/*
* On allocation, reduce the number of pages that are batch freed.
* See nr_pcp_free() where free_factor is increased for subsequent
* frees.
*/
- pcp = this_cpu_ptr(zone->per_cpu_pageset);
pcp->free_factor >>= 1;
list = &pcp->lists[order_to_pindex(migratetype, order)];
page = __rmqueue_pcplist(zone, order, migratetype, alloc_flags, pcp, list);
+ spin_unlock(&pcp->lock);
+ pcp_trylock_finish(UP_flags);
local_unlock_irqrestore(&pagesets.lock, flags);
if (page) {
__count_zid_vm_events(PGALLOC, page_zonenum(page), 1);
migratetype != MIGRATE_MOVABLE) {
page = rmqueue_pcplist(preferred_zone, zone, order,
gfp_flags, migratetype, alloc_flags);
- goto out;
+ if (likely(page))
+ goto out;
}
}
{
struct page *page;
unsigned long flags;
+ unsigned long __maybe_unused UP_flags;
struct zone *zone;
struct zoneref *z;
struct per_cpu_pages *pcp;
if (unlikely(!zone))
goto failed;
- /* Attempt the batch allocation */
+ /* Is a parallel drain in progress? */
local_lock_irqsave(&pagesets.lock, flags);
+ pcp_trylock_prepare(UP_flags);
pcp = this_cpu_ptr(zone->per_cpu_pageset);
- pcp_list = &pcp->lists[order_to_pindex(ac.migratetype, 0)];
+ if (!spin_trylock(&pcp->lock))
+ goto failed_irq;
+ /* Attempt the batch allocation */
+ pcp_list = &pcp->lists[order_to_pindex(ac.migratetype, 0)];
while (nr_populated < nr_pages) {
/* Skip existing pages */
pcp, pcp_list);
if (unlikely(!page)) {
/* Try and allocate at least one page */
- if (!nr_account)
+ if (!nr_account) {
+ spin_unlock(&pcp->lock);
goto failed_irq;
+ }
break;
}
nr_account++;
nr_populated++;
}
+ spin_unlock(&pcp->lock);
+ pcp_trylock_finish(UP_flags);
local_unlock_irqrestore(&pagesets.lock, flags);
__count_zid_vm_events(PGALLOC, zone_idx(zone), nr_account);
return nr_populated;
failed_irq:
+ pcp_trylock_finish(UP_flags);
local_unlock_irqrestore(&pagesets.lock, flags);
failed:
memset(pcp, 0, sizeof(*pcp));
memset(pzstats, 0, sizeof(*pzstats));
+ spin_lock_init(&pcp->lock);
for (pindex = 0; pindex < NR_PCP_LISTS; pindex++)
INIT_LIST_HEAD(&pcp->lists[pindex]);
git.samba.org / sfrench / cifs-2.6.git / blobdiff