| Age | Commit message (Collapse) | Author | |
|---|---|---|---|
| 2023-05-30 | aio: remove aio_disable_external() API | Stefan 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> | |||
| 2023-03-27 | aio-posix: fix race between epoll upgrade and aio_set_fd_handler() | Stefan Hajnoczi | |
| If another thread calls aio_set_fd_handler() while the IOThread event loop is upgrading from ppoll(2) to epoll(7) then we might miss new AioHandlers. The epollfd will not monitor the new AioHandler's fd, resulting in hangs. Take the AioHandler list lock while upgrading to epoll. This prevents AioHandlers from changing while epoll is being set up. If we cannot lock because we're in a nested event loop, then don't upgrade to epoll (it will happen next time we're not in a nested call). The downside to taking the lock is that the aio_set_fd_handler() thread has to wait until the epoll upgrade is finished, which involves many epoll_ctl(2) system calls. However, this scenario is rare and I couldn't think of another solution that is still simple. Reported-by: Qing Wang <qinwang@redhat.com> Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2090998 Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Fam Zheng <fam@euphon.net> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Message-Id: <20230323144859.1338495-1-stefanha@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com> | |||
| 2020-09-23 | qemu/atomic.h: rename atomic_ to qatomic_ | Stefan Hajnoczi | |
| clang's C11 atomic_fetch_*() functions only take a C11 atomic type pointer argument. QEMU uses direct types (int, etc) and this causes a compiler error when a QEMU code calls these functions in a source file that also included <stdatomic.h> via a system header file: $ CC=clang CXX=clang++ ./configure ... && make ../util/async.c:79:17: error: address argument to atomic operation must be a pointer to _Atomic type ('unsigned int *' invalid) Avoid using atomic_*() names in QEMU's atomic.h since that namespace is used by <stdatomic.h>. Prefix QEMU's APIs with 'q' so that atomic.h and <stdatomic.h> can co-exist. I checked /usr/include on my machine and searched GitHub for existing "qatomic_" users but there seem to be none. This patch was generated using: $ git grep -h -o '\<atomic\(64\)\?_[a-z0-9_]\+' include/qemu/atomic.h | \ sort -u >/tmp/changed_identifiers $ for identifier in $(</tmp/changed_identifiers); do sed -i "s%\<$identifier\>%q$identifier%g" \ $(git grep -I -l "\<$identifier\>") done I manually fixed line-wrap issues and misaligned rST tables. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20200923105646.47864-1-stefanha@redhat.com> | |||
| 2020-03-09 | aio-posix: support userspace polling of fd monitoring | Stefan 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> | |||
| 2020-03-09 | aio-posix: simplify FDMonOps->update() prototype | Stefan 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> | |||
| 2020-03-09 | aio-posix: extract ppoll(2) and epoll(7) fd monitoring | Stefan 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> | |||
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