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io_uring: notification completion optimisation

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We want to use all optimisations that we have for io_uring requests like
completion batching, memory caching and more but for zc notifications.
Fortunately, notification perfectly fit the request model so we can
overlay them onto struct io_kiocb and use all the infratructure.

Most of the fields of struct io_notif natively fits into io_kiocb, so we
replace struct io_notif with struct io_kiocb carrying struct
io_notif_data in the cmd cache line. Then we adapt io_alloc_notif() to
use io_alloc_req()/io_alloc_req_refill(), and kill leftovers of hand
coded caching. __io_notif_complete_tw() is converted to use io_uring's
tw infra.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/9e010125175e80baf51f0ca63bdc7cc6a4a9fa56.1658913593.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov
2022-07-27 10:30:41 +01:00
committed by Jens Axboe
parent bd1a3783dd
commit 14b146b688
5 changed files with 65 additions and 146 deletions
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42
io_uring/notif.h
View File

@@ -10,27 +10,10 @@
#define IO_NOTIF_SPLICE_BATCH 32
#define IORING_MAX_NOTIF_SLOTS (1U << 10)
struct io_notif {
struct io_notif_data {
struct file *file;
struct ubuf_info uarg;
struct io_ring_ctx *ctx;
struct io_rsrc_node *rsrc_node;
/* complete via tw if ->task is non-NULL, fallback to wq otherwise */
struct task_struct *task;
/* cqe->user_data, io_notif_slot::tag if not overridden */
u64 tag;
/* see struct io_notif_slot::seq */
u32 seq;
/* hook into ctx->notif_list and ctx->notif_list_locked */
struct list_head cache_node;
unsigned long account_pages;
union {
struct callback_head task_work;
struct work_struct commit_work;
};
};
struct io_notif_slot {
@@ -39,7 +22,7 @@ struct io_notif_slot {
* time and keeps one reference to it. Flush releases the reference and
* lazily replaces it with a new notifier.
*/
struct io_notif *notif;
struct io_kiocb *notif;
/*
* Default ->user_data for this slot notifiers CQEs
@@ -56,13 +39,17 @@ struct io_notif_slot {
int io_notif_register(struct io_ring_ctx *ctx,
void __user *arg, unsigned int size);
int io_notif_unregister(struct io_ring_ctx *ctx);
void io_notif_cache_purge(struct io_ring_ctx *ctx);
void io_notif_slot_flush(struct io_notif_slot *slot);
struct io_notif *io_alloc_notif(struct io_ring_ctx *ctx,
struct io_kiocb *io_alloc_notif(struct io_ring_ctx *ctx,
struct io_notif_slot *slot);
static inline struct io_notif *io_get_notif(struct io_ring_ctx *ctx,
static inline struct io_notif_data *io_notif_to_data(struct io_kiocb *notif)
{
return io_kiocb_to_cmd(notif);
}
static inline struct io_kiocb *io_get_notif(struct io_ring_ctx *ctx,
struct io_notif_slot *slot)
{
if (!slot->notif)
@@ -83,16 +70,13 @@ static inline struct io_notif_slot *io_get_notif_slot(struct io_ring_ctx *ctx,
static inline void io_notif_slot_flush_submit(struct io_notif_slot *slot,
unsigned int issue_flags)
{
if (!(issue_flags & IO_URING_F_UNLOCKED)) {
slot->notif->task = current;
io_get_task_refs(1);
}
io_notif_slot_flush(slot);
}
static inline int io_notif_account_mem(struct io_notif *notif, unsigned len)
static inline int io_notif_account_mem(struct io_kiocb *notif, unsigned len)
{
struct io_ring_ctx *ctx = notif->ctx;
struct io_notif_data *nd = io_notif_to_data(notif);
unsigned nr_pages = (len >> PAGE_SHIFT) + 2;
int ret;
@@ -100,7 +84,7 @@ static inline int io_notif_account_mem(struct io_notif *notif, unsigned len)
ret = __io_account_mem(ctx->user, nr_pages);
if (ret)
return ret;
notif->account_pages += nr_pages;
nd->account_pages += nr_pages;
}
return 0;
}