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Khazhismel Kumykov 0c54a6a44b eventpoll: fix missing wakeup for ovflist in ep_poll_callback
In the event that we add to ovflist, before commit 339ddb53d3
("fs/epoll: remove unnecessary wakeups of nested epoll") we would be
woken up by ep_scan_ready_list, and did no wakeup in ep_poll_callback.

With that wakeup removed, if we add to ovflist here, we may never wake
up.  Rather than adding back the ep_scan_ready_list wakeup - which was
resulting in unnecessary wakeups, trigger a wake-up in ep_poll_callback.

We noticed that one of our workloads was missing wakeups starting with
339ddb53d3 and upon manual inspection, this wakeup seemed missing to me.
With this patch added, we no longer see missing wakeups.  I haven't yet
tried to make a small reproducer, but the existing kselftests in
filesystem/epoll passed for me with this patch.

[khazhy@google.com: use if/elif instead of goto + cleanup suggested by Roman]
  Link: http://lkml.kernel.org/r/20200424190039.192373-1-khazhy@google.com
Fixes: 339ddb53d3 ("fs/epoll: remove unnecessary wakeups of nested epoll")
Signed-off-by: Khazhismel Kumykov <khazhy@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Roman Penyaev <rpenyaev@suse.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Roman Penyaev <rpenyaev@suse.de>
Cc: Heiher <r@hev.cc>
Cc: Jason Baron <jbaron@akamai.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200424025057.118641-1-khazhy@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-05-07 19:27:20 -07:00
arch arch/x86/kvm/svm/sev.c: change flag passed to GUP fast in sev_pin_memory() 2020-05-07 19:27:20 -07:00
block block: remove the bd_openers checks in blk_drop_partitions 2020-04-30 10:25:43 -06:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2020-04-01 14:47:40 -07:00
Documentation Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-05-06 20:53:22 -07:00
drivers Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-05-06 20:53:22 -07:00
fs eventpoll: fix missing wakeup for ovflist in ep_poll_callback 2020-05-07 19:27:20 -07:00
include Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-05-06 20:53:22 -07:00
init Kbuild updates for v5.7 (2nd) 2020-04-11 09:46:12 -07:00
ipc ipc/mqueue.c: change __do_notify() to bypass check_kill_permission() 2020-05-07 19:27:20 -07:00
kernel kernel/kcov.c: fix typos in kcov_remote_start documentation 2020-05-07 19:27:20 -07:00
lib linux-kselftest-kunit-5.7-rc4 2020-04-30 16:32:47 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm/page_alloc: fix watchdog soft lockups during set_zone_contiguous() 2020-05-07 19:27:20 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-05-06 20:53:22 -07:00
samples vmalloc: fix remap_vmalloc_range() bounds checks 2020-04-21 11:11:56 -07:00
scripts scripts/decodecode: fix trapping instruction formatting 2020-05-07 19:27:20 -07:00
security selinux/stable-5.7 PR 20200430 2020-04-30 16:35:45 -07:00
sound sound fixes for 5.7-rc4 2020-05-01 11:05:28 -07:00
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usr kbuild: fix comment about missing include guard detection 2020-04-11 12:09:48 +09:00
virt KVM: Pass kvm_init()'s opaque param to additional arch funcs 2020-03-31 10:48:03 -04:00
.clang-format clang-format: Update with the latest for_each macro list 2020-04-18 13:49:33 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
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.mailmap mailmap: Add Sedat Dilek (replacement for expired email address) 2020-04-11 09:28:34 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Hand MIPS over to Thomas 2020-02-24 22:43:18 -08:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
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MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-05-06 20:53:22 -07:00
Makefile Linux 5.7-rc4 2020-05-03 14:56:04 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.