diff options
| author | Jens Axboe <[email protected]> | 2019-12-28 15:39:54 -0700 |
|---|---|---|
| committer | Jens Axboe <[email protected]> | 2020-01-20 17:04:02 -0700 |
| commit | 8110c1a6212e430a84edd2b83fe9043def8b743e (patch) | |
| tree | 3b7df2807aebe7cec855965c2a077898651e81cf | |
| parent | c6ca97b30c47c7ad36107d3764bb4dc37026d171 (diff) | |
io_uring: add support for IORING_SETUP_CLAMP
Some applications like to start small in terms of ring size, and then
ramp up as needed. This is a bit tricky to do currently, since we don't
advertise the max ring size.
This adds IORING_SETUP_CLAMP. If set, and the values for SQ or CQ ring
size exceed what we support, then clamp them at the max values instead
of returning -EINVAL. Since we return the chosen ring sizes after setup,
no further changes are needed on the application side. io_uring already
changes the ring sizes if the application doesn't ask for power-of-two
sizes, for example.
Signed-off-by: Jens Axboe <[email protected]>
| -rw-r--r-- | fs/io_uring.c | 17 | ||||
| -rw-r--r-- | include/uapi/linux/io_uring.h | 1 |
2 files changed, 15 insertions, 3 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c index 1fbe3eb78d08..7c44b0ef10d7 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -6234,8 +6234,13 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p) bool account_mem; int ret; - if (!entries || entries > IORING_MAX_ENTRIES) + if (!entries) return -EINVAL; + if (entries > IORING_MAX_ENTRIES) { + if (!(p->flags & IORING_SETUP_CLAMP)) + return -EINVAL; + entries = IORING_MAX_ENTRIES; + } /* * Use twice as many entries for the CQ ring. It's possible for the @@ -6252,8 +6257,13 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p) * to a power-of-two, if it isn't already. We do NOT impose * any cq vs sq ring sizing. */ - if (p->cq_entries < p->sq_entries || p->cq_entries > IORING_MAX_CQ_ENTRIES) + if (p->cq_entries < p->sq_entries) return -EINVAL; + if (p->cq_entries > IORING_MAX_CQ_ENTRIES) { + if (!(p->flags & IORING_SETUP_CLAMP)) + return -EINVAL; + p->cq_entries = IORING_MAX_CQ_ENTRIES; + } p->cq_entries = roundup_pow_of_two(p->cq_entries); } else { p->cq_entries = 2 * p->sq_entries; @@ -6345,7 +6355,8 @@ static long io_uring_setup(u32 entries, struct io_uring_params __user *params) } if (p.flags & ~(IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL | - IORING_SETUP_SQ_AFF | IORING_SETUP_CQSIZE)) + IORING_SETUP_SQ_AFF | IORING_SETUP_CQSIZE | + IORING_SETUP_CLAMP)) return -EINVAL; ret = io_uring_create(entries, &p); diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 8ad3cece5440..29fae13395a8 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -61,6 +61,7 @@ struct io_uring_sqe { #define IORING_SETUP_SQPOLL (1U << 1) /* SQ poll thread */ #define IORING_SETUP_SQ_AFF (1U << 2) /* sq_thread_cpu is valid */ #define IORING_SETUP_CQSIZE (1U << 3) /* app defines CQ size */ +#define IORING_SETUP_CLAMP (1U << 4) /* clamp SQ/CQ ring sizes */ enum { IORING_OP_NOP, |