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Commit 1e6fa3a3 authored by Linus Torvalds's avatar Linus Torvalds
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Merge tag 'for-5.4/io_uring-2019-09-15' of git://git.kernel.dk/linux-block 

Pull io_uring updates from Jens Axboe:

 - Allocate SQ/CQ ring together, more efficient. Expose this through a
   feature flag as well, so we can reduce the number of mmaps by 1
   (Hristo and me)

 - Fix for sequence logic with SQ thread (Jackie).

 - Add support for links with drain commands (Jackie).

 - Improved async merging (me)

 - Improved buffered async write performance (me)

 - Support SQ poll wakeup + event get in single io_uring_enter() (me)

 - Support larger SQ ring size. For epoll conversions, the 4k limit was
   too small for some prod workloads (Daniel).

 - put_user_page() usage (John)

* tag 'for-5.4/io_uring-2019-09-15' of git://git.kernel.dk/linux-block:
  io_uring: increase IORING_MAX_ENTRIES to 32K
  io_uring: make sqpoll wakeup possible with getevents
  io_uring: extend async work merging
  io_uring: limit parallelism of buffered writes
  io_uring: add io_queue_async_work() helper
  io_uring: optimize submit_and_wait API
  io_uring: add support for link with drain
  io_uring: fix wrong sequence setting logic
  io_uring: expose single mmap capability
  io_uring: allocate the two rings together
  fs/io_uring.c: convert put_page() to put_user_page*()
parents 7c672abc 5277deaa
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fs/io_uring.c
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......@@ -75,7 +75,7 @@
#include "internal.h"
#define IORING_MAX_ENTRIES 4096
#define IORING_MAX_ENTRIES 32768
#define IORING_MAX_FIXED_FILES 1024
struct io_uring {
......@@ -84,27 +84,29 @@ struct io_uring {
};
/*
* This data is shared with the application through the mmap at offset
* IORING_OFF_SQ_RING.
* This data is shared with the application through the mmap at offsets
* IORING_OFF_SQ_RING and IORING_OFF_CQ_RING.
*
* The offsets to the member fields are published through struct
* io_sqring_offsets when calling io_uring_setup.
*/
struct io_sq_ring {
struct io_rings {
/*
* Head and tail offsets into the ring; the offsets need to be
* masked to get valid indices.
*
* The kernel controls head and the application controls tail.
* The kernel controls head of the sq ring and the tail of the cq ring,
* and the application controls tail of the sq ring and the head of the
* cq ring.
*/
struct io_uring r;
struct io_uring sq, cq;
/*
* Bitmask to apply to head and tail offsets (constant, equals
* Bitmasks to apply to head and tail offsets (constant, equals
* ring_entries - 1)
*/
u32 ring_mask;
/* Ring size (constant, power of 2) */
u32 ring_entries;
u32 sq_ring_mask, cq_ring_mask;
/* Ring sizes (constant, power of 2) */
u32 sq_ring_entries, cq_ring_entries;
/*
* Number of invalid entries dropped by the kernel due to
* invalid index stored in array
......@@ -117,7 +119,7 @@ struct io_sq_ring {
* counter includes all submissions that were dropped reaching
* the new SQ head (and possibly more).
*/
u32 dropped;
u32 sq_dropped;
/*
* Runtime flags
*
......@@ -127,43 +129,7 @@ struct io_sq_ring {
* The application needs a full memory barrier before checking
* for IORING_SQ_NEED_WAKEUP after updating the sq tail.
*/
u32 flags;
/*
* Ring buffer of indices into array of io_uring_sqe, which is
* mmapped by the application using the IORING_OFF_SQES offset.
*
* This indirection could e.g. be used to assign fixed
* io_uring_sqe entries to operations and only submit them to
* the queue when needed.
*
* The kernel modifies neither the indices array nor the entries
* array.
*/
u32 array[];
};
/*
* This data is shared with the application through the mmap at offset
* IORING_OFF_CQ_RING.
*
* The offsets to the member fields are published through struct
* io_cqring_offsets when calling io_uring_setup.
*/
struct io_cq_ring {
/*
* Head and tail offsets into the ring; the offsets need to be
* masked to get valid indices.
*
* The application controls head and the kernel tail.
*/
struct io_uring r;
/*
* Bitmask to apply to head and tail offsets (constant, equals
* ring_entries - 1)
*/
u32 ring_mask;
/* Ring size (constant, power of 2) */
u32 ring_entries;
u32 sq_flags;
/*
* Number of completion events lost because the queue was full;
* this should be avoided by the application by making sure
......@@ -177,7 +143,7 @@ struct io_cq_ring {
* As completion events come in out of order this counter is not
* ordered with any other data.
*/
u32 overflow;
u32 cq_overflow;
/*
* Ring buffer of completion events.
*
......@@ -185,7 +151,7 @@ struct io_cq_ring {
* produced, so the application is allowed to modify pending
* entries.
*/
struct io_uring_cqe cqes[];
struct io_uring_cqe cqes[] ____cacheline_aligned_in_smp;
};
struct io_mapped_ubuf {
......@@ -201,7 +167,7 @@ struct async_list {
struct list_head list;
struct file *file;
off_t io_end;
off_t io_start;
size_t io_len;
};
......@@ -215,8 +181,18 @@ struct io_ring_ctx {
bool compat;
bool account_mem;
/* SQ ring */
struct io_sq_ring *sq_ring;
/*
* Ring buffer of indices into array of io_uring_sqe, which is
* mmapped by the application using the IORING_OFF_SQES offset.
*
* This indirection could e.g. be used to assign fixed
* io_uring_sqe entries to operations and only submit them to
* the queue when needed.
*
* The kernel modifies neither the indices array nor the entries
* array.
*/
u32 *sq_array;
unsigned cached_sq_head;
unsigned sq_entries;
unsigned sq_mask;
......@@ -227,15 +203,13 @@ struct io_ring_ctx {
} ____cacheline_aligned_in_smp;
/* IO offload */
struct workqueue_struct *sqo_wq;
struct workqueue_struct *sqo_wq[2];
struct task_struct *sqo_thread; /* if using sq thread polling */
struct mm_struct *sqo_mm;
wait_queue_head_t sqo_wait;
struct completion sqo_thread_started;
struct {
/* CQ ring */
struct io_cq_ring *cq_ring;
unsigned cached_cq_tail;
unsigned cq_entries;
unsigned cq_mask;
......@@ -244,6 +218,8 @@ struct io_ring_ctx {
struct eventfd_ctx *cq_ev_fd;
} ____cacheline_aligned_in_smp;
struct io_rings *rings;
/*
* If used, fixed file set. Writers must ensure that ->refs is dead,
* readers must ensure that ->refs is alive as long as the file* is
......@@ -288,6 +264,7 @@ struct io_ring_ctx {
struct sqe_submit {
const struct io_uring_sqe *sqe;
unsigned short index;
u32 sequence;
bool has_user;
bool needs_lock;
bool needs_fixed_file;
......@@ -335,6 +312,7 @@ struct io_kiocb {
#define REQ_F_LINK 64 /* linked sqes */
#define REQ_F_LINK_DONE 128 /* linked sqes done */
#define REQ_F_FAIL_LINK 256 /* fail rest of links */
#define REQ_F_SHADOW_DRAIN 512 /* link-drain shadow req */
u64 user_data;
u32 result;
u32 sequence;
......@@ -366,6 +344,7 @@ struct io_submit_state {
};
static void io_sq_wq_submit_work(struct work_struct *work);
static void __io_free_req(struct io_kiocb *req);
static struct kmem_cache *req_cachep;
......@@ -430,7 +409,7 @@ static inline bool io_sequence_defer(struct io_ring_ctx *ctx,
if ((req->flags & (REQ_F_IO_DRAIN|REQ_F_IO_DRAINED)) != REQ_F_IO_DRAIN)
return false;
return req->sequence != ctx->cached_cq_tail + ctx->sq_ring->dropped;
return req->sequence != ctx->cached_cq_tail + ctx->rings->sq_dropped;
}
static struct io_kiocb *io_get_deferred_req(struct io_ring_ctx *ctx)
......@@ -451,11 +430,11 @@ static struct io_kiocb *io_get_deferred_req(struct io_ring_ctx *ctx)
static void __io_commit_cqring(struct io_ring_ctx *ctx)
{
struct io_cq_ring *ring = ctx->cq_ring;
struct io_rings *rings = ctx->rings;
if (ctx->cached_cq_tail != READ_ONCE(ring->r.tail)) {
if (ctx->cached_cq_tail != READ_ONCE(rings->cq.tail)) {
/* order cqe stores with ring update */
smp_store_release(&ring->r.tail, ctx->cached_cq_tail);
smp_store_release(&rings->cq.tail, ctx->cached_cq_tail);
if (wq_has_sleeper(&ctx->cq_wait)) {
wake_up_interruptible(&ctx->cq_wait);
......@@ -464,6 +443,24 @@ static void __io_commit_cqring(struct io_ring_ctx *ctx)
}
}
static inline void io_queue_async_work(struct io_ring_ctx *ctx,
struct io_kiocb *req)
{
int rw;
switch (req->submit.sqe->opcode) {
case IORING_OP_WRITEV:
case IORING_OP_WRITE_FIXED:
rw = !(req->rw.ki_flags & IOCB_DIRECT);
break;
default:
rw = 0;
break;
}
queue_work(ctx->sqo_wq[rw], &req->work);
}
static void io_commit_cqring(struct io_ring_ctx *ctx)
{
struct io_kiocb *req;
......@@ -471,14 +468,19 @@ static void io_commit_cqring(struct io_ring_ctx *ctx)
__io_commit_cqring(ctx);
while ((req = io_get_deferred_req(ctx)) != NULL) {
if (req->flags & REQ_F_SHADOW_DRAIN) {
/* Just for drain, free it. */
__io_free_req(req);
continue;
}
req->flags |= REQ_F_IO_DRAINED;
queue_work(ctx->sqo_wq, &req->work);
io_queue_async_work(ctx, req);
}
}
static struct io_uring_cqe *io_get_cqring(struct io_ring_ctx *ctx)
{
struct io_cq_ring *ring = ctx->cq_ring;
struct io_rings *rings = ctx->rings;
unsigned tail;
tail = ctx->cached_cq_tail;
......@@ -487,11 +489,11 @@ static struct io_uring_cqe *io_get_cqring(struct io_ring_ctx *ctx)
* control dependency is enough as we're using WRITE_ONCE to
* fill the cq entry
*/
if (tail - READ_ONCE(ring->r.head) == ring->ring_entries)
if (tail - READ_ONCE(rings->cq.head) == rings->cq_ring_entries)
return NULL;
ctx->cached_cq_tail++;
return &ring->cqes[tail & ctx->cq_mask];
return &rings->cqes[tail & ctx->cq_mask];
}
static void io_cqring_fill_event(struct io_ring_ctx *ctx, u64 ki_user_data,
......@@ -510,9 +512,9 @@ static void io_cqring_fill_event(struct io_ring_ctx *ctx, u64 ki_user_data,
WRITE_ONCE(cqe->res, res);
WRITE_ONCE(cqe->flags, 0);
} else {
unsigned overflow = READ_ONCE(ctx->cq_ring->overflow);
unsigned overflow = READ_ONCE(ctx->rings->cq_overflow);
WRITE_ONCE(ctx->cq_ring->overflow, overflow + 1);
WRITE_ONCE(ctx->rings->cq_overflow, overflow + 1);
}
}
......@@ -635,7 +637,7 @@ static void io_req_link_next(struct io_kiocb *req)
nxt->flags |= REQ_F_LINK_DONE;
INIT_WORK(&nxt->work, io_sq_wq_submit_work);
queue_work(req->ctx->sqo_wq, &nxt->work);
io_queue_async_work(req->ctx, nxt);
}
}
......@@ -679,11 +681,11 @@ static void io_put_req(struct io_kiocb *req)
io_free_req(req);
}
static unsigned io_cqring_events(struct io_cq_ring *ring)
static unsigned io_cqring_events(struct io_rings *rings)
{
/* See comment at the top of this file */
smp_rmb();
return READ_ONCE(ring->r.tail) - READ_ONCE(ring->r.head);
return READ_ONCE(rings->cq.tail) - READ_ONCE(rings->cq.head);
}
/*
......@@ -836,7 +838,7 @@ static int io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events,
* If we do, we can potentially be spinning for commands that
* already triggered a CQE (eg in error).
*/
if (io_cqring_events(ctx->cq_ring))
if (io_cqring_events(ctx->rings))
break;
/*
......@@ -1187,6 +1189,28 @@ static ssize_t io_import_iovec(struct io_ring_ctx *ctx, int rw,
return import_iovec(rw, buf, sqe_len, UIO_FASTIOV, iovec, iter);
}
static inline bool io_should_merge(struct async_list *al, struct kiocb *kiocb)
{
if (al->file == kiocb->ki_filp) {
off_t start, end;
/*
* Allow merging if we're anywhere in the range of the same
* page. Generally this happens for sub-page reads or writes,
* and it's beneficial to allow the first worker to bring the
* page in and the piggy backed work can then work on the
* cached page.
*/
start = al->io_start & PAGE_MASK;
end = (al->io_start + al->io_len + PAGE_SIZE - 1) & PAGE_MASK;
if (kiocb->ki_pos >= start && kiocb->ki_pos <= end)
return true;
}
al->file = NULL;
return false;
}
/*
* Make a note of the last file/offset/direction we punted to async
* context. We'll use this information to see if we can piggy back a
......@@ -1198,9 +1222,8 @@ static void io_async_list_note(int rw, struct io_kiocb *req, size_t len)
struct async_list *async_list = &req->ctx->pending_async[rw];
struct kiocb *kiocb = &req->rw;
struct file *filp = kiocb->ki_filp;
off_t io_end = kiocb->ki_pos + len;
if (filp == async_list->file && kiocb->ki_pos == async_list->io_end) {
if (io_should_merge(async_list, kiocb)) {
unsigned long max_bytes;
/* Use 8x RA size as a decent limiter for both reads/writes */
......@@ -1213,17 +1236,16 @@ static void io_async_list_note(int rw, struct io_kiocb *req, size_t len)
req->flags |= REQ_F_SEQ_PREV;
async_list->io_len += len;
} else {
io_end = 0;
async_list->io_len = 0;
async_list->file = NULL;
}
}
/* New file? Reset state. */
if (async_list->file != filp) {
async_list->io_len = 0;
async_list->io_start = kiocb->ki_pos;
async_list->io_len = len;
async_list->file = filp;
}
async_list->io_end = io_end;
}
static int io_read(struct io_kiocb *req, const struct sqe_submit *s,
......@@ -1535,7 +1557,7 @@ static void io_poll_remove_one(struct io_kiocb *req)
WRITE_ONCE(poll->canceled, true);
if (!list_empty(&poll->wait.entry)) {
list_del_init(&poll->wait.entry);
queue_work(req->ctx->sqo_wq, &req->work);
io_queue_async_work(req->ctx, req);
}
spin_unlock(&poll->head->lock);
......@@ -1649,7 +1671,7 @@ static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
io_cqring_ev_posted(ctx);
io_put_req(req);
} else {
queue_work(ctx->sqo_wq, &req->work);
io_queue_async_work(ctx, req);
}
return 1;
......@@ -1992,7 +2014,7 @@ static void io_sq_wq_submit_work(struct work_struct *work)
*/
static bool io_add_to_prev_work(struct async_list *list, struct io_kiocb *req)
{
bool ret = false;
bool ret;
if (!list)
return false;
......@@ -2038,10 +2060,14 @@ static int io_req_set_file(struct io_ring_ctx *ctx, const struct sqe_submit *s,
flags = READ_ONCE(s->sqe->flags);
fd = READ_ONCE(s->sqe->fd);
if (flags & IOSQE_IO_DRAIN) {
if (flags & IOSQE_IO_DRAIN)
req->flags |= REQ_F_IO_DRAIN;
req->sequence = ctx->cached_sq_head - 1;
}
/*
* All io need record the previous position, if LINK vs DARIN,
* it can be used to mark the position of the first IO in the
* link list.
*/
req->sequence = s->sequence;
if (!io_op_needs_file(s->sqe))
return 0;
......@@ -2063,21 +2089,12 @@ static int io_req_set_file(struct io_ring_ctx *ctx, const struct sqe_submit *s,
return 0;
}
static int io_queue_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
struct sqe_submit *s)
static int __io_queue_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
struct sqe_submit *s, bool force_nonblock)
{
int ret;
ret = io_req_defer(ctx, req, s->sqe);
if (ret) {
if (ret != -EIOCBQUEUED) {
io_free_req(req);
io_cqring_add_event(ctx, s->sqe->user_data, ret);
}
return 0;
}
ret = __io_submit_sqe(ctx, req, s, true);
ret = __io_submit_sqe(ctx, req, s, force_nonblock);
if (ret == -EAGAIN && !(req->flags & REQ_F_NOWAIT)) {
struct io_uring_sqe *sqe_copy;
......@@ -2094,7 +2111,7 @@ static int io_queue_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
if (list)
atomic_inc(&list->cnt);
INIT_WORK(&req->work, io_sq_wq_submit_work);
queue_work(ctx->sqo_wq, &req->work);
io_queue_async_work(ctx, req);
}
/*
......@@ -2119,10 +2136,70 @@ static int io_queue_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
return ret;
}
static int io_queue_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
struct sqe_submit *s, bool force_nonblock)
{
int ret;
ret = io_req_defer(ctx, req, s->sqe);
if (ret) {
if (ret != -EIOCBQUEUED) {
io_free_req(req);
io_cqring_add_event(ctx, s->sqe->user_data, ret);
}
return 0;
}
return __io_queue_sqe(ctx, req, s, force_nonblock);
}
static int io_queue_link_head(struct io_ring_ctx *ctx, struct io_kiocb *req,
struct sqe_submit *s, struct io_kiocb *shadow,
bool force_nonblock)
{
int ret;
int need_submit = false;
if (!shadow)
return io_queue_sqe(ctx, req, s, force_nonblock);
/*
* Mark the first IO in link list as DRAIN, let all the following
* IOs enter the defer list. all IO needs to be completed before link
* list.
*/
req->flags |= REQ_F_IO_DRAIN;
ret = io_req_defer(ctx, req, s->sqe);
if (ret) {
if (ret != -EIOCBQUEUED) {
io_free_req(req);
io_cqring_add_event(ctx, s->sqe->user_data, ret);
return 0;
}
} else {
/*
* If ret == 0 means that all IOs in front of link io are
* running done. let's queue link head.
*/
need_submit = true;
}
/* Insert shadow req to defer_list, blocking next IOs */
spin_lock_irq(&ctx->completion_lock);
list_add_tail(&shadow->list, &ctx->defer_list);
spin_unlock_irq(&ctx->completion_lock);
if (need_submit)
return __io_queue_sqe(ctx, req, s, force_nonblock);
return 0;
}
#define SQE_VALID_FLAGS (IOSQE_FIXED_FILE|IOSQE_IO_DRAIN|IOSQE_IO_LINK)
static void io_submit_sqe(struct io_ring_ctx *ctx, struct sqe_submit *s,
struct io_submit_state *state, struct io_kiocb **link)
struct io_submit_state *state, struct io_kiocb **link,
bool force_nonblock)
{
struct io_uring_sqe *sqe_copy;
struct io_kiocb *req;
......@@ -2175,7 +2252,7 @@ static void io_submit_sqe(struct io_ring_ctx *ctx, struct sqe_submit *s,
INIT_LIST_HEAD(&req->link_list);
*link = req;
} else {
io_queue_sqe(ctx, req, s);
io_queue_sqe(ctx, req, s, force_nonblock);
}
}
......@@ -2205,15 +2282,15 @@ static void io_submit_state_start(struct io_submit_state *state,
static void io_commit_sqring(struct io_ring_ctx *ctx)
{
struct io_sq_ring *ring = ctx->sq_ring;
struct io_rings *rings = ctx->rings;
if (ctx->cached_sq_head != READ_ONCE(ring->r.head)) {
if (ctx->cached_sq_head != READ_ONCE(rings->sq.head)) {
/*
* Ensure any loads from the SQEs are done at this point,
* since once we write the new head, the application could
* write new data to them.
*/
smp_store_release(&ring->r.head, ctx->cached_sq_head);
smp_store_release(&rings->sq.head, ctx->cached_sq_head);
}
}
......@@ -2227,7 +2304,8 @@ static void io_commit_sqring(struct io_ring_ctx *ctx)
*/
static bool io_get_sqring(struct io_ring_ctx *ctx, struct sqe_submit *s)
{
struct io_sq_ring *ring = ctx->sq_ring;
struct io_rings *rings = ctx->rings;
u32 *sq_array = ctx->sq_array;
unsigned head;
/*
......@@ -2240,20 +2318,21 @@ static bool io_get_sqring(struct io_ring_ctx *ctx, struct sqe_submit *s)
*/
head = ctx->cached_sq_head;
/* make sure SQ entry isn't read before tail */
if (head == smp_load_acquire(&ring->r.tail))
if (head == smp_load_acquire(&rings->sq.tail))
return false;
head = READ_ONCE(ring->array[head & ctx->sq_mask]);
head = READ_ONCE(sq_array[head & ctx->sq_mask]);
if (head < ctx->sq_entries) {
s->index = head;
s->sqe = &ctx->sq_sqes[head];
s->sequence = ctx->cached_sq_head;
ctx->cached_sq_head++;
return true;
}
/* drop invalid entries */
ctx->cached_sq_head++;
ring->dropped++;
rings->sq_dropped++;
return false;
}
......@@ -2262,6 +2341,7 @@ static int io_submit_sqes(struct io_ring_ctx *ctx, struct sqe_submit *sqes,
{
struct io_submit_state state, *statep = NULL;
struct io_kiocb *link = NULL;
struct io_kiocb *shadow_req = NULL;
bool prev_was_link = false;
int i, submitted = 0;
......@@ -2276,11 +2356,21 @@ static int io_submit_sqes(struct io_ring_ctx *ctx, struct sqe_submit *sqes,
* that's the end of the chain. Submit the previous link.
*/
if (!prev_was_link && link) {
io_queue_sqe(ctx, link, &link->submit);
io_queue_link_head(ctx, link, &link->submit, shadow_req,
true);
link = NULL;
}
prev_was_link = (sqes[i].sqe->flags & IOSQE_IO_LINK) != 0;
if (link && (sqes[i].sqe->flags & IOSQE_IO_DRAIN)) {
if (!shadow_req) {
shadow_req = io_get_req(ctx, NULL);
shadow_req->flags |= (REQ_F_IO_DRAIN | REQ_F_SHADOW_DRAIN);
refcount_dec(&shadow_req->refs);
}
shadow_req->sequence = sqes[i].sequence;
}
if (unlikely(mm_fault)) {
io_cqring_add_event(ctx, sqes[i].sqe->user_data,
-EFAULT);
......@@ -2288,13 +2378,13 @@ static int io_submit_sqes(struct io_ring_ctx *ctx, struct sqe_submit *sqes,
sqes[i].has_user = has_user;
sqes[i].needs_lock = true;
sqes[i].needs_fixed_file = true;
io_submit_sqe(ctx, &sqes[i], statep, &link);
io_submit_sqe(ctx, &sqes[i], statep, &link, true);
submitted++;
}
}
if (link)
io_queue_sqe(ctx, link, &link->submit);
io_queue_link_head(ctx, link, &link->submit, shadow_req, true);
if (statep)
io_submit_state_end(&state);
......@@ -2366,7 +2456,7 @@ static int io_sq_thread(void *data)
TASK_INTERRUPTIBLE);
/* Tell userspace we may need a wakeup call */
ctx->sq_ring->flags |= IORING_SQ_NEED_WAKEUP;
ctx->rings->sq_flags |= IORING_SQ_NEED_WAKEUP;
/* make sure to read SQ tail after writing flags */
smp_mb();
......@@ -2380,12 +2470,12 @@ static int io_sq_thread(void *data)
schedule();
finish_wait(&ctx->sqo_wait, &wait);
ctx->sq_ring->flags &= ~IORING_SQ_NEED_WAKEUP;
ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP;
continue;
}
finish_wait(&ctx->sqo_wait, &wait);
ctx->sq_ring->flags &= ~IORING_SQ_NEED_WAKEUP;
ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP;
}
i = 0;
......@@ -2426,10 +2516,12 @@ static int io_sq_thread(void *data)
return 0;
}
static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit)
static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit,
bool block_for_last)
{
struct io_submit_state state, *statep = NULL;
struct io_kiocb *link = NULL;
struct io_kiocb *shadow_req = NULL;
bool prev_was_link = false;
int i, submit = 0;
......@@ -2439,6 +2531,7 @@ static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit)
}
for (i = 0; i < to_submit; i++) {
bool force_nonblock = true;
struct sqe_submit s;
if (!io_get_sqring(ctx, &s))
......@@ -2449,21 +2542,43 @@ static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit)
* that's the end of the chain. Submit the previous link.
*/
if (!prev_was_link && link) {
io_queue_sqe(ctx, link, &link->submit);
io_queue_link_head(ctx, link, &link->submit, shadow_req,
force_nonblock);
link = NULL;
}
prev_was_link = (s.sqe->flags & IOSQE_IO_LINK) != 0;
if (link && (s.sqe->flags & IOSQE_IO_DRAIN)) {
if (!shadow_req) {
shadow_req = io_get_req(ctx, NULL);
shadow_req->flags |= (REQ_F_IO_DRAIN | REQ_F_SHADOW_DRAIN);
refcount_dec(&shadow_req->refs);
}
shadow_req->sequence = s.sequence;
}
s.has_user = true;
s.needs_lock = false;
s.needs_fixed_file = false;
submit++;
io_submit_sqe(ctx, &s, statep, &link);
/*
* The caller will block for events after submit, submit the
* last IO non-blocking. This is either the only IO it's
* submitting, or it already submitted the previous ones. This
* improves performance by avoiding an async punt that we don't
* need to do.
*/
if (block_for_last && submit == to_submit)
force_nonblock = false;
io_submit_sqe(ctx, &s, statep, &link, force_nonblock);
}
io_commit_sqring(ctx);
if (link)
io_queue_sqe(ctx, link, &link->submit);
io_queue_link_head(ctx, link, &link->submit, shadow_req,
block_for_last);
if (statep)
io_submit_state_end(statep);
......@@ -2477,10 +2592,10 @@ static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit)
static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
const sigset_t __user *sig, size_t sigsz)
{
struct io_cq_ring *ring = ctx->cq_ring;
struct io_rings *rings = ctx->rings;
int ret;
if (io_cqring_events(ring) >= min_events)
if (io_cqring_events(rings) >= min_events)
return 0;
if (sig) {
......@@ -2496,12 +2611,12 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
return ret;
}
ret = wait_event_interruptible(ctx->wait, io_cqring_events(ring) >= min_events);
ret = wait_event_interruptible(ctx->wait, io_cqring_events(rings) >= min_events);
restore_saved_sigmask_unless(ret == -ERESTARTSYS);
if (ret == -ERESTARTSYS)
ret = -EINTR;
return READ_ONCE(ring->r.head) == READ_ONCE(ring->r.tail) ? ret : 0;
return READ_ONCE(rings->cq.head) == READ_ONCE(rings->cq.tail) ? ret : 0;
}
static void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
......@@ -2551,11 +2666,15 @@ static void io_sq_thread_stop(struct io_ring_ctx *ctx)
static void io_finish_async(struct io_ring_ctx *ctx)
{
int i;
io_sq_thread_stop(ctx);
if (ctx->sqo_wq) {
destroy_workqueue(ctx->sqo_wq);
ctx->sqo_wq = NULL;
for (i = 0; i < ARRAY_SIZE(ctx->sqo_wq); i++) {
if (ctx->sqo_wq[i]) {
destroy_workqueue(ctx->sqo_wq[i]);
ctx->sqo_wq[i] = NULL;
}
}
}
......@@ -2763,16 +2882,31 @@ static int io_sq_offload_start(struct io_ring_ctx *ctx,
}
/* Do QD, or 2 * CPUS, whatever is smallest */
ctx->sqo_wq = alloc_workqueue("io_ring-wq", WQ_UNBOUND | WQ_FREEZABLE,
ctx->sqo_wq[0] = alloc_workqueue("io_ring-wq",
WQ_UNBOUND | WQ_FREEZABLE,
min(ctx->sq_entries - 1, 2 * num_online_cpus()));
if (!ctx->sqo_wq) {
if (!ctx->sqo_wq[0]) {
ret = -ENOMEM;
goto err;
}
/*
* This is for buffered writes, where we want to limit the parallelism
* due to file locking in file systems. As "normal" buffered writes
* should parellelize on writeout quite nicely, limit us to having 2
* pending. This avoids massive contention on the inode when doing
* buffered async writes.
*/
ctx->sqo_wq[1] = alloc_workqueue("io_ring-write-wq",
WQ_UNBOUND | WQ_FREEZABLE, 2);
if (!ctx->sqo_wq[1]) {
ret = -ENOMEM;
goto err;
}
return 0;
err:
io_sq_thread_stop(ctx);
io_finish_async(ctx);
mmdrop(ctx->sqo_mm);
ctx->sqo_mm = NULL;
return ret;
......@@ -2821,17 +2955,45 @@ static void *io_mem_alloc(size_t size)
return (void *) __get_free_pages(gfp_flags, get_order(size));
}
static unsigned long rings_size(unsigned sq_entries, unsigned cq_entries,
size_t *sq_offset)
{
struct io_rings *rings;
size_t off, sq_array_size;
off = struct_size(rings, cqes, cq_entries);
if (off == SIZE_MAX)
return SIZE_MAX;
#ifdef CONFIG_SMP
off = ALIGN(off, SMP_CACHE_BYTES);
if (off == 0)
return SIZE_MAX;
#endif
sq_array_size = array_size(sizeof(u32), sq_entries);
if (sq_array_size == SIZE_MAX)
return SIZE_MAX;
if (check_add_overflow(off, sq_array_size, &off))
return SIZE_MAX;
if (sq_offset)
*sq_offset = off;
return off;
}
static unsigned long ring_pages(unsigned sq_entries, unsigned cq_entries)
{
struct io_sq_ring *sq_ring;
struct io_cq_ring *cq_ring;
size_t bytes;
size_t pages;
bytes = struct_size(sq_ring, array, sq_entries);
bytes += array_size(sizeof(struct io_uring_sqe), sq_entries);
bytes += struct_size(cq_ring, cqes, cq_entries);
pages = (size_t)1 << get_order(
rings_size(sq_entries, cq_entries, NULL));
pages += (size_t)1 << get_order(
array_size(sizeof(struct io_uring_sqe), sq_entries));
return (bytes + PAGE_SIZE - 1) / PAGE_SIZE;
return pages;
}
static int io_sqe_buffer_unregister(struct io_ring_ctx *ctx)
......@@ -2845,7 +3007,7 @@ static int io_sqe_buffer_unregister(struct io_ring_ctx *ctx)
struct io_mapped_ubuf *imu = &ctx->user_bufs[i];
for (j = 0; j < imu->nr_bvecs; j++)
put_page(imu->bvec[j].bv_page);
put_user_page(imu->bvec[j].bv_page);
if (ctx->account_mem)
io_unaccount_mem(ctx->user, imu->nr_bvecs);
......@@ -2989,10 +3151,8 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg,
* if we did partial map, or found file backed vmas,
* release any pages we did get
*/
if (pret > 0) {
for (j = 0; j < pret; j++)
put_page(pages[j]);
}
if (pret > 0)
put_user_pages(pages, pret);
if (ctx->account_mem)
io_unaccount_mem(ctx->user, nr_pages);
kvfree(imu->bvec);
......@@ -3078,9 +3238,8 @@ static void io_ring_ctx_free(struct io_ring_ctx *ctx)
}
#endif
io_mem_free(ctx->sq_ring);
io_mem_free(ctx->rings);
io_mem_free(ctx->sq_sqes);
io_mem_free(ctx->cq_ring);
percpu_ref_exit(&ctx->refs);
if (ctx->account_mem)
......@@ -3101,10 +3260,10 @@ static __poll_t io_uring_poll(struct file *file, poll_table *wait)
* io_commit_cqring
*/
smp_rmb();
if (READ_ONCE(ctx->sq_ring->r.tail) - ctx->cached_sq_head !=
ctx->sq_ring->ring_entries)
if (READ_ONCE(ctx->rings->sq.tail) - ctx->cached_sq_head !=
ctx->rings->sq_ring_entries)
mask |= EPOLLOUT | EPOLLWRNORM;
if (READ_ONCE(ctx->cq_ring->r.head) != ctx->cached_cq_tail)
if (READ_ONCE(ctx->rings->sq.head) != ctx->cached_cq_tail)
mask |= EPOLLIN | EPOLLRDNORM;
return mask;
......@@ -3149,14 +3308,12 @@ static int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
switch (offset) {
case IORING_OFF_SQ_RING:
ptr = ctx->sq_ring;
case IORING_OFF_CQ_RING:
ptr = ctx->rings;
break;
case IORING_OFF_SQES:
ptr = ctx->sq_sqes;
break;
case IORING_OFF_CQ_RING:
ptr = ctx->cq_ring;
break;
default:
return -EINVAL;
}
......@@ -3199,19 +3356,27 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
* Just return the requested submit count, and wake the thread if
* we were asked to.
*/
ret = 0;
if (ctx->flags & IORING_SETUP_SQPOLL) {
if (flags & IORING_ENTER_SQ_WAKEUP)
wake_up(&ctx->sqo_wait);
submitted = to_submit;
goto out_ctx;
}
} else if (to_submit) {
bool block_for_last = false;
ret = 0;
if (to_submit) {
to_submit = min(to_submit, ctx->sq_entries);
/*
* Allow last submission to block in a series, IFF the caller
* asked to wait for events and we don't currently have
* enough. This potentially avoids an async punt.
*/
if (to_submit == min_complete &&
io_cqring_events(ctx->rings) < min_complete)
block_for_last = true;
mutex_lock(&ctx->uring_lock);
submitted = io_ring_submit(ctx, to_submit);
submitted = io_ring_submit(ctx, to_submit, block_for_last);
mutex_unlock(&ctx->uring_lock);
}
if (flags & IORING_ENTER_GETEVENTS) {
......@@ -3226,7 +3391,6 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
}
}
out_ctx:
io_ring_drop_ctx_refs(ctx, 1);
out_fput:
fdput(f);
......@@ -3243,19 +3407,27 @@ static const struct file_operations io_uring_fops = {
static int io_allocate_scq_urings(struct io_ring_ctx *ctx,
struct io_uring_params *p)
{
struct io_sq_ring *sq_ring;
struct io_cq_ring *cq_ring;
size_t size;
struct io_rings *rings;
size_t size, sq_array_offset;
sq_ring = io_mem_alloc(struct_size(sq_ring, array, p->sq_entries));
if (!sq_ring)
size = rings_size(p->sq_entries, p->cq_entries, &sq_array_offset);
if (size == SIZE_MAX)
return -EOVERFLOW;
rings = io_mem_alloc(size);
if (!rings)
return -ENOMEM;
ctx->sq_ring = sq_ring;
sq_ring->ring_mask = p->sq_entries - 1;
sq_ring->ring_entries = p->sq_entries;
ctx->sq_mask = sq_ring->ring_mask;
ctx->sq_entries = sq_ring->ring_entries;
ctx->rings = rings;
ctx->sq_array = (u32 *)((char *)rings + sq_array_offset);
rings->sq_ring_mask = p->sq_entries - 1;
rings->cq_ring_mask = p->cq_entries - 1;
rings->sq_ring_entries = p->sq_entries;
rings->cq_ring_entries = p->cq_entries;
ctx->sq_mask = rings->sq_ring_mask;
ctx->cq_mask = rings->cq_ring_mask;
ctx->sq_entries = rings->sq_ring_entries;
ctx->cq_entries = rings->cq_ring_entries;
size = array_size(sizeof(struct io_uring_sqe), p->sq_entries);
if (size == SIZE_MAX)
......@@ -3265,15 +3437,6 @@ static int io_allocate_scq_urings(struct io_ring_ctx *ctx,
if (!ctx->sq_sqes)
return -ENOMEM;
cq_ring = io_mem_alloc(struct_size(cq_ring, cqes, p->cq_entries));
if (!cq_ring)
return -ENOMEM;
ctx->cq_ring = cq_ring;
cq_ring->ring_mask = p->cq_entries - 1;
cq_ring->ring_entries = p->cq_entries;
ctx->cq_mask = cq_ring->ring_mask;
ctx->cq_entries = cq_ring->ring_entries;
return 0;
}
......@@ -3377,21 +3540,23 @@ static int io_uring_create(unsigned entries, struct io_uring_params *p)
goto err;
memset(&p->sq_off, 0, sizeof(p->sq_off));
p->sq_off.head = offsetof(struct io_sq_ring, r.head);
p->sq_off.tail = offsetof(struct io_sq_ring, r.tail);
p->sq_off.ring_mask = offsetof(struct io_sq_ring, ring_mask);
p->sq_off.ring_entries = offsetof(struct io_sq_ring, ring_entries);
p->sq_off.flags = offsetof(struct io_sq_ring, flags);
p->sq_off.dropped = offsetof(struct io_sq_ring, dropped);
p->sq_off.array = offsetof(struct io_sq_ring, array);
p->sq_off.head = offsetof(struct io_rings, sq.head);
p->sq_off.tail = offsetof(struct io_rings, sq.tail);
p->sq_off.ring_mask = offsetof(struct io_rings, sq_ring_mask);
p->sq_off.ring_entries = offsetof(struct io_rings, sq_ring_entries);
p->sq_off.flags = offsetof(struct io_rings, sq_flags);
p->sq_off.dropped = offsetof(struct io_rings, sq_dropped);
p->sq_off.array = (char *)ctx->sq_array - (char *)ctx->rings;
memset(&p->cq_off, 0, sizeof(p->cq_off));
p->cq_off.head = offsetof(struct io_cq_ring, r.head);
p->cq_off.tail = offsetof(struct io_cq_ring, r.tail);
p->cq_off.ring_mask = offsetof(struct io_cq_ring, ring_mask);
p->cq_off.ring_entries = offsetof(struct io_cq_ring, ring_entries);
p->cq_off.overflow = offsetof(struct io_cq_ring, overflow);
p->cq_off.cqes = offsetof(struct io_cq_ring, cqes);
p->cq_off.head = offsetof(struct io_rings, cq.head);
p->cq_off.tail = offsetof(struct io_rings, cq.tail);
p->cq_off.ring_mask = offsetof(struct io_rings, cq_ring_mask);
p->cq_off.ring_entries = offsetof(struct io_rings, cq_ring_entries);
p->cq_off.overflow = offsetof(struct io_rings, cq_overflow);
p->cq_off.cqes = offsetof(struct io_rings, cqes);
p->features = IORING_FEAT_SINGLE_MMAP;
return ret;
err:
io_ring_ctx_wait_and_kill(ctx);
......
include/uapi/linux/io_uring.h
View file @ 1e6fa3a3
......@@ -128,11 +128,17 @@ struct io_uring_params {
__u32 flags;
__u32 sq_thread_cpu;
__u32 sq_thread_idle;
__u32 resv[5];
__u32 features;
__u32 resv[4];
struct io_sqring_offsets sq_off;
struct io_cqring_offsets cq_off;
};
/*
* io_uring_params->features flags
*/
#define IORING_FEAT_SINGLE_MMAP (1U << 0)
/*
* io_uring_register(2) opcodes and arguments
*/
......
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