Date: Sun, 21 Mar 2021 07:06:18 GMT From: Dmitry Chagin <dchagin@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org Subject: git: bf1863de6b1f - stable/12 - linux: make timerfd_settime(2) set expirations count to zero Message-ID: <202103210706.12L76IhV023477@gitrepo.freebsd.org>
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The branch stable/12 has been updated by dchagin: URL: https://cgit.FreeBSD.org/src/commit/?id=bf1863de6b1fb813192e45639b4cfde65a624b6b commit bf1863de6b1fb813192e45639b4cfde65a624b6b Author: shu <ankohuu@outlook.com> AuthorDate: 2021-02-03 16:51:45 +0000 Commit: Dmitry Chagin <dchagin@FreeBSD.org> CommitDate: 2021-03-21 07:03:22 +0000 linux: make timerfd_settime(2) set expirations count to zero On Linux, read(2) from a timerfd file descriptor returns an unsigned 8-byte integer (uint64_t) containing the number of expirations that have occurred, if the timer has already expired one or more times since its settings were last modified using timerfd_settime(), or since the last successful read(2). That's to say, once we do a read or call timerfd_settime(), timer fd's expiration count should be zero. Some Linux applications create timerfd and add it to epoll with LT mode, when event comes, they do timerfd_settime instead of read to stop event source from trigger. On FreeBSD, timerfd_settime(2) didn't set the count to zero, which caused high CPU utilization. PR: 252820 Submitted by: ankohuu_outlook.com (Shunchao Hu) Differential Revision: https://reviews.freebsd.org/D28231 (cherry picked from commit ae71b794cbed19e5e25effc3438720ad452ab87c) --- sys/compat/linux/linux_event.c | 1 + 1 file changed, 1 insertion(+) diff --git a/sys/compat/linux/linux_event.c b/sys/compat/linux/linux_event.c index 498471fd7dd1..b1d88eb3f402 100644 --- a/sys/compat/linux/linux_event.c +++ b/sys/compat/linux/linux_event.c @@ -1276,6 +1276,7 @@ linux_timerfd_settime(struct thread *td, struct linux_timerfd_settime_args *args linux_timerfd_curval(tfd, &ots); tfd->tfd_time = nts; + tfd->tfd_count = 0; if (timespecisset(&nts.it_value)) { linux_timerfd_clocktime(tfd, &cts); ts = nts.it_value;
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