On 01/18/2018 05:46 PM, Jeff Moyer wrote:
FYI, this kernel has issues. It will boot up, but I don't have networking, and even rebooting doesn't succeed. I'm looking into it.
FWIW, I'm running an older version of this patchset on my desktop with no problems so far.
-Jeff Christoph Hellwig <hch@xxxxxx> writes:Hi all, this series adds support for the IOCB_CMD_POLL operation to poll for the readyness of file descriptors using the aio subsystem. The API is based on patches that existed in RHAS2.1 and RHEL3, which means it already is supported by libaio. To implement the poll support efficiently new methods to poll are introduced in struct file_operations: get_poll_head and poll_mask. The first one returns a wait_queue_head to wait on (lifetime is bound by the file), and the second does a non-blocking check for the POLL* events. This allows aio poll to work without any additional context switches, unlike epoll. To make the interface fully useful a new io_pgetevents system call is added, which atomically saves and restores the signal mask over the io_pgetevents system call. It it the logical equivalent to pselect and ppoll for io_pgetevents. The corresponding libaio changes for io_pgetevents support and documentation, as well as a test case will be posted in a separate series. The changes were sponsored by Scylladb, and improve performance of the seastar framework up to 10%, while also removing the need for a privileged SCHED_FIFO epoll listener thread. The patches are on top of Als __poll_t annoations, so I've also prepared a git branch on top of those here: git://git.infradead.org/users/hch/vfs.git aio-poll.3 Gitweb: http://git.infradead.org/users/hch/vfs.git/shortlog/refs/heads/aio-poll.3 Libaio changes: https://pagure.io/libaio.git io-poll Seastar changes (not updated for the new io_pgetevens ABI yet): https://github.com/avikivity/seastar/commits/aio Changes since V2: - removed a double initialization - new vfs_get_poll_head helper - document that ->get_poll_head can return NULL - call ->poll_mask before sleeping - various ACKs - add conversion of random to ->poll_mask - add conversion of af_alg to ->poll_mask - lacking ->poll_mask support now returns -EINVAL for IOCB_CMD_POLL - reshuffled the series so that prep patches and everything not requiring the new in-kernel poll API is in the beginning Changes since V1: - handle the NULL ->poll case in vfs_poll - dropped the file argument to the ->poll_mask socket operation - replace the ->pre_poll socket operation with ->get_poll_head as in the file operations -- To unsubscribe, send a message with 'unsubscribe linux-aio' in the body to majordomo@xxxxxxxxx. For more info on Linux AIO, see: http://www.kvack.org/aio/ Don't email: <a href=mailto:"aart@xxxxxxxxx";>aart@xxxxxxxxx</a>
