diff options
Diffstat (limited to 'mm/compaction.c')
| -rw-r--r-- | mm/compaction.c | 25 |
1 files changed, 19 insertions, 6 deletions
diff --git a/mm/compaction.c b/mm/compaction.c index 5ab9c2b22693..a0e19d40ecc2 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -2241,10 +2241,12 @@ check_drain: block_start_pfn(cc->migrate_pfn, cc->order); if (last_migrated_pfn < current_block_start) { - cpu = get_cpu(); + cpu = get_cpu_light(); + local_lock_irq(swapvec_lock); lru_add_drain_cpu(cpu); + local_unlock_irq(swapvec_lock); drain_local_pages(cc->zone); - put_cpu(); + put_cpu_light(); /* No more flushing until we migrate again */ last_migrated_pfn = 0; } @@ -2311,16 +2313,26 @@ static enum compact_result compact_zone_order(struct zone *zone, int order, .page = NULL, }; - if (capture) - current->capture_control = &capc; + /* + * Make sure the structs are really initialized before we expose the + * capture control, in case we are interrupted and the interrupt handler + * frees a page. + */ + barrier(); + WRITE_ONCE(current->capture_control, &capc); ret = compact_zone(&cc, &capc); VM_BUG_ON(!list_empty(&cc.freepages)); VM_BUG_ON(!list_empty(&cc.migratepages)); - *capture = capc.page; - current->capture_control = NULL; + /* + * Make sure we hide capture control first before we read the captured + * page pointer, otherwise an interrupt could free and capture a page + * and we would leak it. + */ + WRITE_ONCE(current->capture_control, NULL); + *capture = READ_ONCE(capc.page); return ret; } @@ -2334,6 +2346,7 @@ int sysctl_extfrag_threshold = 500; * @alloc_flags: The allocation flags of the current allocation * @ac: The context of current allocation * @prio: Determines how hard direct compaction should try to succeed + * @capture: Pointer to free page created by compaction will be stored here * * This is the main entry point for direct page compaction. */ |