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author | Wang Sheng-Hui <shhuiw@foxmail.com> | 2016-06-09 00:33:56 +0200 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-06-09 23:23:11 +0200 |
commit | f3a932baa7f65072434f1c04c02c8a4d2746fcfc (patch) | |
tree | 82a75a1d6fc3b7113b7530646918d64b4e18da88 | |
parent | kernel/relay.c: fix potential memory leak (diff) | |
download | linux-f3a932baa7f65072434f1c04c02c8a4d2746fcfc.tar.xz linux-f3a932baa7f65072434f1c04c02c8a4d2746fcfc.zip |
mm: introduce dedicated WQ_MEM_RECLAIM workqueue to do lru_add_drain_all
This patch is based on https://patchwork.ozlabs.org/patch/574623/.
Tejun submitted commit 23d11a58a9a6 ("workqueue: skip flush dependency
checks for legacy workqueues") for the legacy create*_workqueue()
interface.
But some workq created by alloc_workqueue still reports warning on
memory reclaim, e.g nvme_workq with flag WQ_MEM_RECLAIM set:
workqueue: WQ_MEM_RECLAIM nvme:nvme_reset_work is flushing !WQ_MEM_RECLAIM events:lru_add_drain_per_cpu
------------[ cut here ]------------
WARNING: CPU: 0 PID: 6 at SoC/linux/kernel/workqueue.c:2448 check_flush_dependency+0xb4/0x10c
...
check_flush_dependency+0xb4/0x10c
flush_work+0x54/0x140
lru_add_drain_all+0x138/0x188
migrate_prep+0xc/0x18
alloc_contig_range+0xf4/0x350
cma_alloc+0xec/0x1e4
dma_alloc_from_contiguous+0x38/0x40
__dma_alloc+0x74/0x25c
nvme_alloc_queue+0xcc/0x36c
nvme_reset_work+0x5c4/0xda8
process_one_work+0x128/0x2ec
worker_thread+0x58/0x434
kthread+0xd4/0xe8
ret_from_fork+0x10/0x50
That's because lru_add_drain_all() will schedule the drain work on
system_wq, whose flag is set to 0, !WQ_MEM_RECLAIM.
Introduce a dedicated WQ_MEM_RECLAIM workqueue to do
lru_add_drain_all(), aiding in getting memory freed.
Link: http://lkml.kernel.org/r/1464917521-9775-1-git-send-email-shhuiw@foxmail.com
Signed-off-by: Wang Sheng-Hui <shhuiw@foxmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thierry Reding <treding@nvidia.com>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r-- | mm/swap.c | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/mm/swap.c b/mm/swap.c index 95916142fc46..59f5fafa6e1f 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -667,6 +667,24 @@ static void lru_add_drain_per_cpu(struct work_struct *dummy) static DEFINE_PER_CPU(struct work_struct, lru_add_drain_work); +/* + * lru_add_drain_wq is used to do lru_add_drain_all() from a WQ_MEM_RECLAIM + * workqueue, aiding in getting memory freed. + */ +static struct workqueue_struct *lru_add_drain_wq; + +static int __init lru_init(void) +{ + lru_add_drain_wq = alloc_workqueue("lru-add-drain", WQ_MEM_RECLAIM, 0); + + if (WARN(!lru_add_drain_wq, + "Failed to create workqueue lru_add_drain_wq")) + return -ENOMEM; + + return 0; +} +early_initcall(lru_init); + void lru_add_drain_all(void) { static DEFINE_MUTEX(lock); @@ -686,7 +704,7 @@ void lru_add_drain_all(void) pagevec_count(&per_cpu(lru_deactivate_pvecs, cpu)) || need_activate_page_drain(cpu)) { INIT_WORK(work, lru_add_drain_per_cpu); - schedule_work_on(cpu, work); + queue_work_on(cpu, lru_add_drain_wq, work); cpumask_set_cpu(cpu, &has_work); } } |