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@xxxxxxxxx> --- 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 d0242e5c8d0a..97113c71e881 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), -- 2.36.1
