Avi Kivity <avi@xxxxxxxxxxxx> writes: > 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. Right, it's worth mentioning that v1 worked fine for me. -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> > > > -- > 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>
