io_uring: replace list with stack for req caches
Replace struct list_head free_list serving for caching requests with
singly linked stack, which is faster.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1bc942b82422fb2624b8353bd93aca183a022846.1632516769.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/fs/io_uring.c b/fs/io_uring.c
index e3bfbd3..90ad9cd 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -319,7 +319,7 @@ struct io_submit_state {
struct io_wq_work_list compl_reqs;
/* inline/task_work completion list, under ->uring_lock */
- struct list_head free_list;
+ struct io_wq_work_node free_list;
};
struct io_ring_ctx {
@@ -379,7 +379,7 @@ struct io_ring_ctx {
} ____cacheline_aligned_in_smp;
/* IRQ completion list, under ->completion_lock */
- struct list_head locked_free_list;
+ struct io_wq_work_list locked_free_list;
unsigned int locked_free_nr;
const struct cred *sq_creds; /* cred used for __io_sq_thread() */
@@ -1318,8 +1318,8 @@ static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
INIT_DELAYED_WORK(&ctx->rsrc_put_work, io_rsrc_put_work);
init_llist_head(&ctx->rsrc_put_llist);
INIT_LIST_HEAD(&ctx->tctx_list);
- INIT_LIST_HEAD(&ctx->submit_state.free_list);
- INIT_LIST_HEAD(&ctx->locked_free_list);
+ ctx->submit_state.free_list.next = NULL;
+ INIT_WQ_LIST(&ctx->locked_free_list);
INIT_DELAYED_WORK(&ctx->fallback_work, io_fallback_req_func);
INIT_WQ_LIST(&ctx->submit_state.compl_reqs);
return ctx;
@@ -1806,7 +1806,7 @@ static void io_req_complete_post(struct io_kiocb *req, long res,
}
io_dismantle_req(req);
io_put_task(req->task, 1);
- list_add(&req->inflight_entry, &ctx->locked_free_list);
+ wq_list_add_head(&req->comp_list, &ctx->locked_free_list);
ctx->locked_free_nr++;
percpu_ref_put(&ctx->refs);
}
@@ -1883,7 +1883,7 @@ static void io_flush_cached_locked_reqs(struct io_ring_ctx *ctx,
struct io_submit_state *state)
{
spin_lock(&ctx->completion_lock);
- list_splice_init(&ctx->locked_free_list, &state->free_list);
+ wq_list_splice(&ctx->locked_free_list, &state->free_list);
ctx->locked_free_nr = 0;
spin_unlock(&ctx->completion_lock);
}
@@ -1900,7 +1900,7 @@ static bool io_flush_cached_reqs(struct io_ring_ctx *ctx)
*/
if (READ_ONCE(ctx->locked_free_nr) > IO_COMPL_BATCH)
io_flush_cached_locked_reqs(ctx, state);
- return !list_empty(&state->free_list);
+ return !!state->free_list.next;
}
/*
@@ -1915,10 +1915,11 @@ static struct io_kiocb *io_alloc_req(struct io_ring_ctx *ctx)
struct io_submit_state *state = &ctx->submit_state;
gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;
void *reqs[IO_REQ_ALLOC_BATCH];
+ struct io_wq_work_node *node;
struct io_kiocb *req;
int ret, i;
- if (likely(!list_empty(&state->free_list) || io_flush_cached_reqs(ctx)))
+ if (likely(state->free_list.next || io_flush_cached_reqs(ctx)))
goto got_req;
ret = kmem_cache_alloc_bulk(req_cachep, gfp, ARRAY_SIZE(reqs), reqs);
@@ -1938,12 +1939,11 @@ static struct io_kiocb *io_alloc_req(struct io_ring_ctx *ctx)
req = reqs[i];
io_preinit_req(req, ctx);
- list_add(&req->inflight_entry, &state->free_list);
+ wq_stack_add_head(&req->comp_list, &state->free_list);
}
got_req:
- req = list_first_entry(&state->free_list, struct io_kiocb, inflight_entry);
- list_del(&req->inflight_entry);
- return req;
+ node = wq_stack_extract(&state->free_list);
+ return container_of(node, struct io_kiocb, comp_list);
}
static inline void io_put_file(struct file *file)
@@ -1976,7 +1976,7 @@ static void __io_free_req(struct io_kiocb *req)
io_put_task(req->task, 1);
spin_lock(&ctx->completion_lock);
- list_add(&req->inflight_entry, &ctx->locked_free_list);
+ wq_list_add_head(&req->comp_list, &ctx->locked_free_list);
ctx->locked_free_nr++;
spin_unlock(&ctx->completion_lock);
@@ -2300,8 +2300,7 @@ static void io_req_free_batch(struct req_batch *rb, struct io_kiocb *req,
}
rb->task_refs++;
rb->ctx_refs++;
-
- list_add(&req->inflight_entry, &state->free_list);
+ wq_stack_add_head(&req->comp_list, &state->free_list);
}
static void __io_submit_flush_completions(struct io_ring_ctx *ctx)
@@ -7261,7 +7260,7 @@ static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr)
}
sqe = io_get_sqe(ctx);
if (unlikely(!sqe)) {
- list_add(&req->inflight_entry, &ctx->submit_state.free_list);
+ wq_stack_add_head(&req->comp_list, &ctx->submit_state.free_list);
break;
}
/* will complete beyond this point, count as submitted */
@@ -9193,23 +9192,21 @@ static void io_destroy_buffers(struct io_ring_ctx *ctx)
}
}
-static void io_req_cache_free(struct list_head *list)
-{
- struct io_kiocb *req, *nxt;
-
- list_for_each_entry_safe(req, nxt, list, inflight_entry) {
- list_del(&req->inflight_entry);
- kmem_cache_free(req_cachep, req);
- }
-}
-
static void io_req_caches_free(struct io_ring_ctx *ctx)
{
struct io_submit_state *state = &ctx->submit_state;
mutex_lock(&ctx->uring_lock);
io_flush_cached_locked_reqs(ctx, state);
- io_req_cache_free(&state->free_list);
+
+ while (state->free_list.next) {
+ struct io_wq_work_node *node;
+ struct io_kiocb *req;
+
+ node = wq_stack_extract(&state->free_list);
+ req = container_of(node, struct io_kiocb, comp_list);
+ kmem_cache_free(req_cachep, req);
+ }
mutex_unlock(&ctx->uring_lock);
}
