summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorJens Axboe <axboe@kernel.dk>2021-02-10 00:03:19 +0000
committerJens Axboe <axboe@kernel.dk>2021-02-10 07:28:43 -0700
commit1b4c351f6eb7467c77fc19e0cd7e5f0083ecd847 (patch)
tree7c8a680982902bcaa4ca9934fb07eb3fd5626098
parent6ff119a6e4c3fe900e75e6667930dc086f185f2b (diff)
io_uring: use persistent request cache
Now that we have the submit_state in the ring itself, we can have io_kiocb allocations that are persistent across invocations. This reduces the time spent doing slab allocations and frees. [sil: rebased] Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r--fs/io_uring.c48
1 files changed, 30 insertions, 18 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c
index fe07af756186..87a4b727fe1c 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -270,8 +270,9 @@ struct io_sq_data {
#define IO_REQ_ALLOC_BATCH 8
struct io_comp_state {
- unsigned int nr;
struct io_kiocb *reqs[IO_COMPL_BATCH];
+ unsigned int nr;
+ struct list_head free_list;
};
struct io_submit_state {
@@ -1341,6 +1342,7 @@ static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
INIT_LIST_HEAD(&ctx->rsrc_ref_list);
INIT_DELAYED_WORK(&ctx->rsrc_put_work, io_rsrc_put_work);
init_llist_head(&ctx->rsrc_put_llist);
+ INIT_LIST_HEAD(&ctx->submit_state.comp.free_list);
return ctx;
err:
kfree(ctx->cancel_hash);
@@ -1946,6 +1948,15 @@ static struct io_kiocb *io_alloc_req(struct io_ring_ctx *ctx)
BUILD_BUG_ON(IO_REQ_ALLOC_BATCH > ARRAY_SIZE(state->reqs));
+ if (!list_empty(&state->comp.free_list)) {
+ struct io_kiocb *req;
+
+ req = list_first_entry(&state->comp.free_list, struct io_kiocb,
+ compl.list);
+ list_del(&req->compl.list);
+ return req;
+ }
+
if (!state->free_reqs) {
gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;
int ret;
@@ -2228,34 +2239,21 @@ static void io_free_req(struct io_kiocb *req)
}
struct req_batch {
- void *reqs[IO_IOPOLL_BATCH];
- int to_free;
- int ctx_refs;
-
struct task_struct *task;
int task_refs;
+ int ctx_refs;
};
static inline void io_init_req_batch(struct req_batch *rb)
{
- rb->to_free = 0;
rb->task_refs = 0;
rb->ctx_refs = 0;
rb->task = NULL;
}
-static void __io_req_free_batch_flush(struct io_ring_ctx *ctx,
- struct req_batch *rb)
-{
- kmem_cache_free_bulk(req_cachep, rb->to_free, rb->reqs);
- rb->to_free = 0;
-}
-
static void io_req_free_batch_finish(struct io_ring_ctx *ctx,
struct req_batch *rb)
{
- if (rb->to_free)
- __io_req_free_batch_flush(ctx, rb);
if (rb->task) {
io_put_task(rb->task, rb->task_refs);
rb->task = NULL;
@@ -2282,9 +2280,9 @@ static void io_req_free_batch(struct req_batch *rb, struct io_kiocb *req,
if (state->free_reqs != ARRAY_SIZE(state->reqs)) {
state->reqs[state->free_reqs++] = req;
} else {
- rb->reqs[rb->to_free++] = req;
- if (unlikely(rb->to_free == ARRAY_SIZE(rb->reqs)))
- __io_req_free_batch_flush(req->ctx, rb);
+ struct io_comp_state *cs = &req->ctx->submit_state.comp;
+
+ list_add(&req->compl.list, &cs->free_list);
}
}
@@ -8634,6 +8632,19 @@ static void io_destroy_buffers(struct io_ring_ctx *ctx)
idr_destroy(&ctx->io_buffer_idr);
}
+static void io_req_cache_free(struct io_ring_ctx *ctx)
+{
+ struct io_comp_state *cs = &ctx->submit_state.comp;
+
+ while (!list_empty(&cs->free_list)) {
+ struct io_kiocb *req;
+
+ req = list_first_entry(&cs->free_list, struct io_kiocb, compl.list);
+ list_del(&req->compl.list);
+ kmem_cache_free(req_cachep, req);
+ }
+}
+
static void io_ring_ctx_free(struct io_ring_ctx *ctx)
{
struct io_submit_state *submit_state = &ctx->submit_state;
@@ -8676,6 +8687,7 @@ static void io_ring_ctx_free(struct io_ring_ctx *ctx)
free_uid(ctx->user);
put_cred(ctx->creds);
kfree(ctx->cancel_hash);
+ io_req_cache_free(ctx);
kfree(ctx);
}