ping? On Mon, Mar 05, 2018 at 01:27:07PM -0800, Christoph Hellwig wrote: > 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. > > git://git.infradead.org/users/hch/vfs.git aio-poll.5 > > Gitweb: > > http://git.infradead.org/users/hch/vfs.git/shortlog/refs/heads/aio-poll.5 > > 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 V4: > - rebased ontop of Linux 4.16-rc4 > > Changes since V3: > - remove the pre-sleep ->poll_mask call in vfs_poll, > allow ->get_poll_head to return POLL* values. > > 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 ---end quoted text--- -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
