From: Pavel Begunkov <[email protected]>
To: [email protected]
Cc: Jens Axboe <[email protected]>, [email protected]
Subject: [PATCH for-next 18/25] io_uring: limit number hash buckets
Date: Tue, 14 Jun 2022 13:29:56 +0100 [thread overview]
Message-ID: <94334f242fa236c77e1f2c32a9b0108931e285a2.1655209709.git.asml.silence@gmail.com> (raw)
In-Reply-To: <[email protected]>
Don't allocate to many hash/cancellation buckets, there might be too
many, clamp it to 8 bits, or 256 * 64B = 16KB. We don't usually have too
many requests, and 256 buckets should be enough, especially since we
do hash search only in the cancellation path.
Signed-off-by: Pavel Begunkov <[email protected]>
---
io_uring/io_uring.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 4e0f60ffc975..a203943f3d71 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -710,12 +710,12 @@ static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
/*
* Use 5 bits less than the max cq entries, that should give us around
- * 32 entries per hash list if totally full and uniformly spread.
+ * 32 entries per hash list if totally full and uniformly spread, but
+ * don't keep too many buckets to not overconsume memory.
*/
- hash_bits = ilog2(p->cq_entries);
- hash_bits -= 5;
- if (hash_bits <= 0)
- hash_bits = 1;
+ hash_bits = ilog2(p->cq_entries) - 5;
+ hash_bits = clamp(hash_bits, 1, 8);
+
ctx->cancel_hash_bits = hash_bits;
ctx->cancel_hash =
kmalloc((1U << hash_bits) * sizeof(struct io_hash_bucket),
--
2.36.1
next prev parent reply other threads:[~2022-06-14 12:34 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-14 12:29 [PATCH for-next 00/25] 5.20 cleanups and poll optimisations Pavel Begunkov
2022-06-14 12:29 ` [PATCH for-next 01/25] io_uring: make reg buf init consistent Pavel Begunkov
2022-06-14 12:29 ` [PATCH for-next 02/25] io_uring: move defer_list to slow data Pavel Begunkov
2022-06-14 12:29 ` [PATCH for-next 03/25] io_uring: better caching for ctx timeout fields Pavel Begunkov
2022-06-14 12:29 ` [PATCH for-next 04/25] io_uring: refactor ctx slow data placement Pavel Begunkov
2022-06-14 12:29 ` [PATCH for-next 05/25] io_uring: move cancel_seq out of io-wq Pavel Begunkov
2022-06-14 12:52 ` Jens Axboe
2022-06-14 13:01 ` Pavel Begunkov
2022-06-14 13:10 ` Jens Axboe
2022-06-14 12:29 ` [PATCH for-next 06/25] io_uring: move small helpers to headers Pavel Begunkov
2022-06-14 12:29 ` [PATCH for-next 07/25] io_uring: inline ->registered_rings Pavel Begunkov
2022-06-14 12:29 ` [PATCH for-next 08/25] io_uring: don't set REQ_F_COMPLETE_INLINE in tw Pavel Begunkov
2022-06-14 12:29 ` [PATCH for-next 09/25] io_uring: never defer-complete multi-apoll Pavel Begunkov
2022-06-14 12:29 ` [PATCH for-next 10/25] io_uring: kill REQ_F_COMPLETE_INLINE Pavel Begunkov
2022-06-14 12:29 ` [PATCH for-next 11/25] io_uring: refactor io_req_task_complete() Pavel Begunkov
2022-06-14 12:29 ` [PATCH for-next 12/25] io_uring: don't inline io_put_kbuf Pavel Begunkov
2022-06-14 12:29 ` [PATCH for-next 13/25] io_uring: remove check_cq checking from hot paths Pavel Begunkov
2022-06-14 12:29 ` [PATCH for-next 14/25] io_uring: poll: remove unnecessary req->ref set Pavel Begunkov
2022-06-14 12:29 ` [PATCH for-next 15/25] io_uring: switch cancel_hash to use per entry spinlock Pavel Begunkov
2022-06-14 12:29 ` [PATCH for-next 16/25] io_uring: pass poll_find lock back Pavel Begunkov
2022-06-14 12:29 ` [PATCH for-next 17/25] io_uring: clean up io_try_cancel Pavel Begunkov
2022-06-14 12:29 ` Pavel Begunkov [this message]
2022-06-14 12:29 ` [PATCH for-next 19/25] io_uring: clean up io_ring_ctx_alloc Pavel Begunkov
2022-06-14 12:29 ` [PATCH for-next 20/25] io_uring: use state completion infra for poll reqs Pavel Begunkov
2022-06-14 12:29 ` [PATCH for-next 21/25] io_uring: add IORING_SETUP_SINGLE_ISSUER Pavel Begunkov
2022-06-14 12:56 ` Pavel Begunkov
2022-06-14 12:30 ` [PATCH for-next 22/25] io_uring: pass hash table into poll_find Pavel Begunkov
2022-06-14 12:30 ` [PATCH for-next 23/25] io_uring: introduce a struct for hash table Pavel Begunkov
2022-06-14 12:30 ` [PATCH for-next 24/25] io_uring: propagate locking state to poll cancel Pavel Begunkov
2022-06-14 12:30 ` [PATCH for-next 25/25] io_uring: mutex locked poll hashing Pavel Begunkov
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