On Wed, Oct 16, 2024 at 03:10:34PM +0200, Christian Brauner wrote: > On Fri, 26 Apr 2024 16:05:48 +0800, Xuewen Yan wrote: > > Now, the epoll only use wake_up() interface to wake up task. > > However, sometimes, there are epoll users which want to use > > the synchronous wakeup flag to hint the scheduler, such as > > Android binder driver. > > So add a wake_up_sync() define, and use the wake_up_sync() > > when the sync is true in ep_poll_callback(). > > > > [...] > > Applied to the vfs.misc branch of the vfs/vfs.git tree. > Patches in the vfs.misc branch should appear in linux-next soon. > > Please report any outstanding bugs that were missed during review in a > new review to the original patch series allowing us to drop it. > > It's encouraged to provide Acked-bys and Reviewed-bys even though the > patch has now been applied. If possible patch trailers will be updated. > > Note that commit hashes shown below are subject to change due to rebase, > trailer updates or similar. If in doubt, please check the listed branch. > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git > branch: vfs.misc This is a bug that's been present for all of time, so I think we should: Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@xxxxxxxxxxxxxxx I sent a patch which adds a benchmark for nonblocking pipes using epoll: https://lore.kernel.org/lkml/20241016190009.866615-1-bgeffon@xxxxxxxxxx/ Using this new benchmark I get the following results without this fix and with this fix: $ tools/perf/perf bench sched pipe -n # Running 'sched/pipe' benchmark: # Executed 1000000 pipe operations between two processes Total time: 12.194 [sec] 12.194376 usecs/op 82005 ops/sec $ tools/perf/perf bench sched pipe -n # Running 'sched/pipe' benchmark: # Executed 1000000 pipe operations between two processes Total time: 9.229 [sec] 9.229738 usecs/op 108345 ops/sec > > [1/1] epoll: Add synchronous wakeup support for ep_poll_callback > https://git.kernel.org/vfs/vfs/c/2ce0e17660a7
