From: Soheil Hassas Yeganeh <soheil.kdev@gmail.com>
To: torvalds@linux-foundation.org, viro@zeniv.linux.org.uk,
linux-fsdevel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
dave@stgolabs.net, edumazet@google.com, willemb@google.com,
khazhy@google.com, guantaol@google.com,
Soheil Hassas Yeganeh <soheil@google.com>
Subject: [PATCH 6/8] epoll: pull all code between fetch_events and send_event into the loop
Date: Fri, 6 Nov 2020 18:16:33 -0500 [thread overview]
Message-ID: <20201106231635.3528496-7-soheil.kdev@gmail.com> (raw)
In-Reply-To: <20201106231635.3528496-1-soheil.kdev@gmail.com>
From: Soheil Hassas Yeganeh <soheil@google.com>
This is a no-op change which simplifies the follow up patches.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Khazhismel Kumykov <khazhy@google.com>
---
fs/eventpoll.c | 41 +++++++++++++++++++++--------------------
1 file changed, 21 insertions(+), 20 deletions(-)
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 28c1d341d2e6..b29bbebe8ca4 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -1861,14 +1861,14 @@ static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events,
}
fetch_events:
- eavail = ep_events_available(ep);
- if (!eavail)
- eavail = ep_busy_loop(ep, timed_out);
+ do {
+ eavail = ep_events_available(ep);
+ if (!eavail)
+ eavail = ep_busy_loop(ep, timed_out);
- if (eavail)
- goto send_events;
+ if (eavail)
+ goto send_events;
- do {
if (signal_pending(current))
return -EINTR;
@@ -1917,21 +1917,22 @@ static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events,
* carefully under lock, below.
*/
eavail = 1;
- } while (0);
- if (!list_empty_careful(&wait.entry)) {
- write_lock_irq(&ep->lock);
- /*
- * If the thread timed out and is not on the wait queue, it
- * means that the thread was woken up after its timeout expired
- * before it could reacquire the lock. Thus, when wait.entry is
- * empty, it needs to harvest events.
- */
- if (timed_out)
- eavail = list_empty(&wait.entry);
- __remove_wait_queue(&ep->wq, &wait);
- write_unlock_irq(&ep->lock);
- }
+ if (!list_empty_careful(&wait.entry)) {
+ write_lock_irq(&ep->lock);
+ /*
+ * If the thread timed out and is not on the wait queue,
+ * it means that the thread was woken up after its
+ * timeout expired before it could reacquire the lock.
+ * Thus, when wait.entry is empty, it needs to harvest
+ * events.
+ */
+ if (timed_out)
+ eavail = list_empty(&wait.entry);
+ __remove_wait_queue(&ep->wq, &wait);
+ write_unlock_irq(&ep->lock);
+ }
+ } while (0);
send_events:
/*
--
2.29.1.341.ge80a0c044ae-goog
next prev parent reply other threads:[~2020-11-06 23:18 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-06 23:16 [PATCH 0/8] simplify ep_poll Soheil Hassas Yeganeh
2020-11-06 23:16 ` [PATCH 1/8] epoll: check for events when removing a timed out thread from the wait queue Soheil Hassas Yeganeh
2020-11-10 6:05 ` Davidlohr Bueso
2020-11-06 23:16 ` [PATCH 2/8] epoll: simplify signal handling Soheil Hassas Yeganeh
2020-11-06 23:16 ` [PATCH 3/8] epoll: pull fatal signal checks into ep_send_events() Soheil Hassas Yeganeh
2020-11-06 23:16 ` [PATCH 4/8] epoll: move eavail next to the list_empty_careful check Soheil Hassas Yeganeh
2020-11-06 23:16 ` [PATCH 5/8] epoll: simplify and optimize busy loop logic Soheil Hassas Yeganeh
2020-11-06 23:16 ` Soheil Hassas Yeganeh [this message]
2020-11-06 23:16 ` [PATCH 7/8] epoll: replace gotos with a proper loop Soheil Hassas Yeganeh
2020-11-06 23:16 ` [PATCH 8/8] epoll: eliminate unnecessary lock for zero timeout Soheil Hassas Yeganeh
2020-11-06 23:35 ` [PATCH 0/8] simplify ep_poll Linus Torvalds
2020-11-08 1:43 ` Andrew Morton
2020-11-08 4:45 ` Soheil Hassas Yeganeh
2020-11-09 18:59 ` Davidlohr Bueso
2020-11-09 19:28 ` Soheil Hassas Yeganeh
2020-11-10 22:05 ` Andrew Morton
2020-11-11 3:37 ` Soheil Hassas Yeganeh
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