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| author | Pavel Begunkov <asml.silence@gmail.com> | 2022-06-16 11:22:12 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2022-07-25 02:39:14 +0200 |
| commit | 9ca9fb24d5febccea354089c41f96a8ad0d853f8 (patch) | |
| tree | 1a08b01d113fce77e375769430ea06f40c2280d4 /io_uring/io_uring.c | |
| parent | io_uring: propagate locking state to poll cancel (diff) | |
| download | linux-9ca9fb24d5febccea354089c41f96a8ad0d853f8.tar.xz linux-9ca9fb24d5febccea354089c41f96a8ad0d853f8.zip | |
io_uring: mutex locked poll hashing
Currently we do two extra spin lock/unlock pairs to add a poll/apoll
request to the cancellation hash table and remove it from there.
On the submission side we often already hold ->uring_lock and tw
completion is likely to hold it as well. Add a second cancellation hash
table protected by ->uring_lock. In concerns for latency because of a
need to have the mutex locked on the completion side, use the new table
only in following cases:
1) IORING_SETUP_SINGLE_ISSUER: only one task grabs uring_lock, so there
is little to no contention and so the main tw hander will almost
always end up grabbing it before calling callbacks.
2) IORING_SETUP_SQPOLL: same as with single issuer, only one task is
a major user of ->uring_lock.
3) apoll: we normally grab the lock on the completion side anyway to
execute the request, so it's free.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1bbad9c78c454b7b92f100bbf46730a37df7194f.1655371007.git.asml.silence@gmail.com
Reviewed-by: Hao Xu <howeyxu@tencent.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring/io_uring.c')
| -rw-r--r-- | io_uring/io_uring.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 0b3851a0db2b..eeda16731795 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -275,6 +275,8 @@ static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p) hash_bits = clamp(hash_bits, 1, 8); if (io_alloc_hash_table(&ctx->cancel_table, hash_bits)) goto err; + if (io_alloc_hash_table(&ctx->cancel_table_locked, hash_bits)) + goto err; ctx->dummy_ubuf = kzalloc(sizeof(*ctx->dummy_ubuf), GFP_KERNEL); if (!ctx->dummy_ubuf) @@ -317,6 +319,7 @@ static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p) err: kfree(ctx->dummy_ubuf); kfree(ctx->cancel_table.hbs); + kfree(ctx->cancel_table_locked.hbs); kfree(ctx->io_bl); xa_destroy(&ctx->io_bl_xa); kfree(ctx); @@ -2493,6 +2496,7 @@ static __cold void io_ring_ctx_free(struct io_ring_ctx *ctx) if (ctx->hash_map) io_wq_put_hash(ctx->hash_map); kfree(ctx->cancel_table.hbs); + kfree(ctx->cancel_table_locked.hbs); kfree(ctx->dummy_ubuf); kfree(ctx->io_bl); xa_destroy(&ctx->io_bl_xa); @@ -2654,12 +2658,13 @@ static __cold void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx) __io_cqring_overflow_flush(ctx, true); xa_for_each(&ctx->personalities, index, creds) io_unregister_personality(ctx, index); + if (ctx->rings) + io_poll_remove_all(ctx, NULL, true); mutex_unlock(&ctx->uring_lock); /* failed during ring init, it couldn't have issued any requests */ if (ctx->rings) { io_kill_timeouts(ctx, NULL, true); - io_poll_remove_all(ctx, NULL, true); /* if we failed setting up the ctx, we might not have any rings */ io_iopoll_try_reap_events(ctx); } @@ -2784,7 +2789,9 @@ static __cold void io_uring_try_cancel_requests(struct io_ring_ctx *ctx, } ret |= io_cancel_defer_files(ctx, task, cancel_all); + mutex_lock(&ctx->uring_lock); ret |= io_poll_remove_all(ctx, task, cancel_all); + mutex_unlock(&ctx->uring_lock); ret |= io_kill_timeouts(ctx, task, cancel_all); if (task) ret |= io_run_task_work(); |