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2023-05-30aio: remove aio_disable_external() APIStefan Hajnoczi
All callers now pass is_external=false to aio_set_fd_handler() and aio_set_event_notifier(). The aio_disable_external() API that temporarily disables fd handlers that were registered is_external=true is therefore dead code. Remove aio_disable_external(), aio_enable_external(), and the is_external arguments to aio_set_fd_handler() and aio_set_event_notifier(). The entire test-fdmon-epoll test is removed because its sole purpose was testing aio_disable_external(). Parts of this patch were generated using the following coccinelle (https://coccinelle.lip6.fr/) semantic patch: @@ expression ctx, fd, is_external, io_read, io_write, io_poll, io_poll_ready, opaque; @@ - aio_set_fd_handler(ctx, fd, is_external, io_read, io_write, io_poll, io_poll_ready, opaque) + aio_set_fd_handler(ctx, fd, io_read, io_write, io_poll, io_poll_ready, opaque) @@ expression ctx, notifier, is_external, io_read, io_poll, io_poll_ready; @@ - aio_set_event_notifier(ctx, notifier, is_external, io_read, io_poll, io_poll_ready) + aio_set_event_notifier(ctx, notifier, io_read, io_poll, io_poll_ready) Reviewed-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20230516190238.8401-21-stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2020-09-23fdmon-poll: reset npfd when upgrading to fdmon-epollStefan Hajnoczi
npfd keeps track of how many pollfds are currently being monitored. It must be reset to 0 when fdmon_poll_wait() returns. When npfd reaches a treshold we switch to fdmon-epoll because it scales better. This patch resets npfd in the case where we switch to fdmon-epoll. Forgetting to do so results in the following assertion failure: util/fdmon-poll.c:65: fdmon_poll_wait: Assertion `npfd == 0' failed. Fixes: 1f050a4690f62a1e7dabc4f44141e9f762c3769f ("aio-posix: extract ppoll(2) and epoll(7) fd monitoring") Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1869952 Message-Id: <20200915120339.702938-2-stefanha@redhat.com>
2020-03-09aio-posix: support userspace polling of fd monitoringStefan Hajnoczi
Unlike ppoll(2) and epoll(7), Linux io_uring completions can be polled from userspace. Previously userspace polling was only allowed when all AioHandler's had an ->io_poll() callback. This prevented starvation of fds by userspace pollable handlers. Add the FDMonOps->need_wait() callback that enables userspace polling even when some AioHandlers lack ->io_poll(). For example, it's now possible to do userspace polling when a TCP/IP socket is monitored thanks to Linux io_uring. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Link: https://lore.kernel.org/r/20200305170806.1313245-7-stefanha@redhat.com Message-Id: <20200305170806.1313245-7-stefanha@redhat.com>
2020-03-09aio-posix: simplify FDMonOps->update() prototypeStefan Hajnoczi
The AioHandler *node, bool is_new arguments are more complicated to think about than simply being given AioHandler *old_node, AioHandler *new_node. Furthermore, the new Linux io_uring file descriptor monitoring mechanism added by the new patch requires access to both the old and the new nodes. Make this change now in preparation. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Link: https://lore.kernel.org/r/20200305170806.1313245-5-stefanha@redhat.com Message-Id: <20200305170806.1313245-5-stefanha@redhat.com>
2020-03-09aio-posix: extract ppoll(2) and epoll(7) fd monitoringStefan Hajnoczi
The ppoll(2) and epoll(7) file descriptor monitoring implementations are mixed with the core util/aio-posix.c code. Before adding another implementation for Linux io_uring, extract out the existing ones so there is a clear interface and the core code is simpler. The new interface is AioContext->fdmon_ops, a pointer to a FDMonOps struct. See the patch for details. Semantic changes: 1. ppoll(2) now reflects events from pollfds[] back into AioHandlers while we're still on the clock for adaptive polling. This was already happening for epoll(7), so if it's really an issue then we'll need to fix both in the future. 2. epoll(7)'s fallback to ppoll(2) while external events are disabled was broken when the number of fds exceeded the epoll(7) upgrade threshold. I guess this code path simply wasn't tested and no one noticed the bug. I didn't go out of my way to fix it but the correct code is simpler than preserving the bug. I also took some liberties in removing the unnecessary AioContext->epoll_available (just check AioContext->epollfd != -1 instead) and AioContext->epoll_enabled (it's implicit if our AioContext->fdmon_ops callbacks are being invoked) fields. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Link: https://lore.kernel.org/r/20200305170806.1313245-4-stefanha@redhat.com Message-Id: <20200305170806.1313245-4-stefanha@redhat.com>