Roman Penyaev 474328c06e kselftests: introduce new epoll60 testcase for catching lost wakeups ... This test case catches lost wake up introduced by commit 339ddb53d3 ("fs/epoll: remove unnecessary wakeups of nested epoll") The test is simple: we have 10 threads and 10 event fds. Each thread can harvest only 1 event. 1 producer fires all 10 events at once and waits that all 10 events will be observed by 10 threads. In case of lost wakeup epoll_wait() will timeout and 0 will be returned. Test case catches two sort of problems: forgotten wakeup on event, which hits the ->ovflist list, this problem was fixed by: 5a2513239750 ("eventpoll: fix missing wakeup for ovflist in ep_poll_callback") the other problem is when several sequential events hit the same waiting thread, thus other waiters get no wakeups. Problem is fixed in the following patch. Signed-off-by: Roman Penyaev <rpenyaev@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Khazhismel Kumykov <khazhy@google.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Heiher <r@hev.cc> Cc: Jason Baron <jbaron@akamai.com> Link: http://lkml.kernel.org/r/20200430130326.1368509-1-rpenyaev@suse.de Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2020-05-07 19:27:21 -07:00
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.gitignore	.gitignore: add SPDX License Identifier	2020-03-25 11:50:48 +01:00
epoll_wakeup_test.c	kselftests: introduce new epoll60 testcase for catching lost wakeups	2020-05-07 19:27:21 -07:00
Makefile