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io_uring: batch put_task_struct()

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As every iopoll request have a task ref, it becomes expensive to put
them one by one, instead we can put several at once integrating that
into io_req_free_batch().

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2020-07-18 11:32:52 +03:00 committed by Jens Axboe
parent dd6f843a9f
commit 5af1d13e8f
1 changed files with 27 additions and 2 deletions
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29
fs/io_uring.c
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@ -1544,7 +1544,6 @@ static void io_dismantle_req(struct io_kiocb *req)
kfree(req->io);
if (req->file)
io_put_file(req, req->file, (req->flags & REQ_F_FIXED_FILE));
__io_put_req_task(req);
io_req_clean_work(req);
if (req->flags & REQ_F_INFLIGHT) {
@ -1564,6 +1563,7 @@ static void __io_free_req(struct io_kiocb *req)
struct io_ring_ctx *ctx;
io_dismantle_req(req);
__io_put_req_task(req);
ctx = req->ctx;
if (likely(!io_is_fallback_req(req)))
kmem_cache_free(req_cachep, req);
@ -1807,8 +1807,18 @@ static void io_free_req(struct io_kiocb *req)
struct req_batch {
void *reqs[IO_IOPOLL_BATCH];
int to_free;
struct task_struct *task;
int task_refs;
};
static inline void io_init_req_batch(struct req_batch *rb)
{
rb->to_free = 0;
rb->task_refs = 0;
rb->task = NULL;
}
static void __io_req_free_batch_flush(struct io_ring_ctx *ctx,
struct req_batch *rb)
{
@ -1822,6 +1832,10 @@ static void io_req_free_batch_finish(struct io_ring_ctx *ctx,
{
if (rb->to_free)
__io_req_free_batch_flush(ctx, rb);
if (rb->task) {
put_task_struct_many(rb->task, rb->task_refs);
rb->task = NULL;
}
}
static void io_req_free_batch(struct req_batch *rb, struct io_kiocb *req)
@ -1833,6 +1847,17 @@ static void io_req_free_batch(struct req_batch *rb, struct io_kiocb *req)
if (req->flags & REQ_F_LINK_HEAD)
io_queue_next(req);
if (req->flags & REQ_F_TASK_PINNED) {
if (req->task != rb->task) {
if (rb->task)
put_task_struct_many(rb->task, rb->task_refs);
rb->task = req->task;
rb->task_refs = 0;
}
rb->task_refs++;
req->flags &= ~REQ_F_TASK_PINNED;
}
io_dismantle_req(req);
rb->reqs[rb->to_free++] = req;
if (unlikely(rb->to_free == ARRAY_SIZE(rb->reqs)))
@ -1978,7 +2003,7 @@ static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events,
/* order with ->result store in io_complete_rw_iopoll() */
smp_rmb();
rb.to_free = 0;
io_init_req_batch(&rb);
while (!list_empty(done)) {
int cflags = 0;