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io_uring: batch io_kiocb allocation 

Similarly to how we use the state->ios_left to know how many references
to get to a file, we can use it to allocate the io_kiocb's we need in
bulk.

Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2019-01-09 09:10:43 -07:00
parent 9a56a2323d
commit 2579f913d4
1 changed files with 38 additions and 7 deletions
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45
fs/io_uring.c
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@ -168,6 +168,13 @@ struct io_kiocb {
struct io_submit_state {
struct blk_plug plug;
/*
* io_kiocb alloc cache
*/
void *reqs[IO_IOPOLL_BATCH];
unsigned int free_reqs;
unsigned int cur_req;
/*
* File reference cache
*/
@ -305,20 +312,40 @@ static void io_ring_drop_ctx_refs(struct io_ring_ctx *ctx, unsigned refs)
wake_up(&ctx->wait);
}
static struct io_kiocb *io_get_req(struct io_ring_ctx *ctx)
static struct io_kiocb *io_get_req(struct io_ring_ctx *ctx,
struct io_submit_state *state)
{
struct io_kiocb *req;
if (!percpu_ref_tryget(&ctx->refs))
return NULL;
req = kmem_cache_alloc(req_cachep, __GFP_NOWARN);
if (req) {
req->ctx = ctx;
req->flags = 0;
return req;
if (!state) {
req = kmem_cache_alloc(req_cachep, __GFP_NOWARN);
if (unlikely(!req))
goto out;
} else if (!state->free_reqs) {
size_t sz;
int ret;
sz = min_t(size_t, state->ios_left, ARRAY_SIZE(state->reqs));
ret = kmem_cache_alloc_bulk(req_cachep, __GFP_NOWARN, sz,
state->reqs);
if (unlikely(ret <= 0))
goto out;
state->free_reqs = ret - 1;
state->cur_req = 1;
req = state->reqs[0];
} else {
req = state->reqs[state->cur_req];
state->free_reqs--;
state->cur_req++;
}
req->ctx = ctx;
req->flags = 0;
return req;
out:
io_ring_drop_ctx_refs(ctx, 1);
return NULL;
}
@ -1007,7 +1034,7 @@ static int io_submit_sqe(struct io_ring_ctx *ctx, struct sqe_submit *s,
if (unlikely(s->sqe->flags))
return -EINVAL;
req = io_get_req(ctx);
req = io_get_req(ctx, state);
if (unlikely(!req))
return -EAGAIN;
@ -1041,6 +1068,9 @@ static void io_submit_state_end(struct io_submit_state *state)
{
blk_finish_plug(&state->plug);
io_file_put(state, NULL);
if (state->free_reqs)
kmem_cache_free_bulk(req_cachep, state->free_reqs,
&state->reqs[state->cur_req]);
}
/*
@ -1050,6 +1080,7 @@ static void io_submit_state_start(struct io_submit_state *state,
struct io_ring_ctx *ctx, unsigned max_ios)
{
blk_start_plug(&state->plug);
state->free_reqs = 0;
state->file = NULL;
state->ios_left = max_ios;
}