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aio-posix: add io_uring fd monitoring implementation

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The recent Linux io_uring API has several advantages over ppoll(2) and
epoll(2).  Details are given in the source code.

Add an io_uring implementation and make it the default on Linux.
Performance is the same as with epoll(7) but later patches add
optimizations that take advantage of io_uring.

It is necessary to change how aio_set_fd_handler() deals with deleting
AioHandlers since removing monitored file descriptors is asynchronous in
io_uring.  fdmon_io_uring_remove() marks the AioHandler deleted and
aio_set_fd_handler() will let it handle deletion in that case.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Link: https://lore.kernel.org/r/20200305170806.1313245-6-stefanha@redhat.com
Message-Id: <20200305170806.1313245-6-stefanha@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2020-03-05 17:08:04 +00:00
parent b321051cf4
commit 73fd282e7b
6 changed files with 376 additions and 5 deletions
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20
util/aio-posix.h
View file

@ -27,10 +27,14 @@ struct AioHandler {
IOHandler *io_poll_begin;
IOHandler *io_poll_end;
void *opaque;
bool is_external;
QLIST_ENTRY(AioHandler) node;
QLIST_ENTRY(AioHandler) node_ready; /* only used during aio_poll() */
QLIST_ENTRY(AioHandler) node_deleted;
#ifdef CONFIG_LINUX_IO_URING
QSLIST_ENTRY(AioHandler) node_submitted;
unsigned flags; /* see fdmon-io_uring.c */
#endif
bool is_external;
};
/* Add a handler to a ready list */
@ -58,4 +62,18 @@ static inline void fdmon_epoll_disable(AioContext *ctx)
}
#endif /* !CONFIG_EPOLL_CREATE1 */
#ifdef CONFIG_LINUX_IO_URING
bool fdmon_io_uring_setup(AioContext *ctx);
void fdmon_io_uring_destroy(AioContext *ctx);
#else
static inline bool fdmon_io_uring_setup(AioContext *ctx)
{
return false;
}
static inline void fdmon_io_uring_destroy(AioContext *ctx)
{
}
#endif /* !CONFIG_LINUX_IO_URING */
#endif /* AIO_POSIX_H */