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io_uring: use persistent request cache

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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>
This commit is contained in:
Jens Axboe 2021-02-10 00:03:19 +00:00
parent 6ff119a6e4
commit 1b4c351f6e
1 changed files with 30 additions and 18 deletions
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48
fs/io_uring.c
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@ -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);
}