diff options
| author | Pavel Begunkov <asml.silence@gmail.com> | 2022-06-16 10:22:05 +0100 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2022-07-24 18:39:13 -0600 |
| commit | 4a07723fb4bb2568a31d43709904ab0d4c33d6c8 (patch) | |
| tree | 5653ef6d2eb9e95a9f7b729914d70f1e8b96eaef /io_uring/io_uring.c | |
| parent | 4dfab8abb4721da278a2ccd45c1b6a69f8a9dd14 (diff) | |
io_uring: limit the number of cancellation buckets
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 <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/b9620c8072ba61a2d50eba894b89bd93a94a9abd.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 | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index ac6946e3f174..aafdf1330ec6 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -254,12 +254,12 @@ 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), |