izzy/xemu
0
0
Fork 0
mirror of https://github.com/izzy2lost/xemu.git synced 2026-07-06 00:20:22 -07:00
Code Issues Packages Projects Releases Wiki Activity

block/io_uring: use aio_add_sqe()

Browse Source 
AioContext has its own io_uring instance for file descriptor monitoring.
The disk I/O io_uring code was developed separately. Originally I
thought the characteristics of file descriptor monitoring and disk I/O
were too different, requiring separate io_uring instances.

Now it has become clear to me that it's feasible to share a single
io_uring instance for file descriptor monitoring and disk I/O. We're not
using io_uring's IOPOLL feature or anything else that would require a
separate instance.

Unify block/io_uring.c and util/fdmon-io_uring.c using the new
aio_add_sqe() API that allows user-defined io_uring sqe submission. Now
block/io_uring.c just needs to submit readv/writev/fsync and most of the
io_uring-specific logic is handled by fdmon-io_uring.c.

There are two immediate advantages:
1. Fewer system calls. There is no need to monitor the disk I/O io_uring
   ring fd from the file descriptor monitoring io_uring instance. Disk
   I/O completions are now picked up directly. Also, sqes are
   accumulated in the sq ring until the end of the event loop iteration
   and there are fewer io_uring_enter(2) syscalls.
2. Less code duplication.

Note that error_setg() messages are not supposed to end with
punctuation, so I removed a '.' for the non-io_uring build error
message.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-ID: <20251104022933.618123-15-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Stefan Hajnoczi
2025-11-11 22:06:09 +01:00
committed by Kevin Wolf
parent 1eebdab3c3
commit 047dabef97
8 changed files with 130 additions and 493 deletions
Download Patch File Download Diff File Expand all files Collapse all files
include/block/aio.h
-7
View File
@@ -310,8 +310,6 @@ struct AioContext {
struct LinuxAioState *linux_aio;
#endif
#ifdef CONFIG_LINUX_IO_URING
LuringState *linux_io_uring;
/* State for file descriptor monitoring using Linux io_uring */
struct io_uring fdmon_io_uring;
AioHandlerSList submit_list;
@@ -615,11 +613,6 @@ struct LinuxAioState *aio_setup_linux_aio(AioContext *ctx, Error **errp);
/* Return the LinuxAioState bound to this AioContext */
struct LinuxAioState *aio_get_linux_aio(AioContext *ctx);
/* Setup the LuringState bound to this AioContext */
LuringState *aio_setup_linux_io_uring(AioContext *ctx, Error **errp);
/* Return the LuringState bound to this AioContext */
LuringState *aio_get_linux_io_uring(AioContext *ctx);
/**
* aio_timer_new_with_attrs:
* @ctx: the aio context
include/block/raw-aio.h
-5
View File
@@ -74,15 +74,10 @@ static inline bool laio_has_fua(void)
#endif
/* io_uring.c - Linux io_uring implementation */
#ifdef CONFIG_LINUX_IO_URING
LuringState *luring_init(Error **errp);
void luring_cleanup(LuringState *s);
/* luring_co_submit: submit I/O requests in the thread's current AioContext. */
int coroutine_fn luring_co_submit(BlockDriverState *bs, int fd, uint64_t offset,
QEMUIOVector *qiov, int type,
BdrvRequestFlags flags);
void luring_detach_aio_context(LuringState *s, AioContext *old_context);
void luring_attach_aio_context(LuringState *s, AioContext *new_context);
bool luring_has_fua(void);
#else
static inline bool luring_has_fua(void)