lkml.org 
[lkml]   [2022]   [Oct]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 5.4 048/255] ring-buffer: Have the shortest_full queue be the shortest not longest
Date
From: Steven Rostedt (Google) <rostedt@goodmis.org>

commit 3b19d614b61b93a131f463817e08219c9ce1fee3 upstream.

The logic to know when the shortest waiters on the ring buffer should be
woken up or not has uses a less than instead of a greater than compare,
which causes the shortest_full to actually be the longest.

Link: https://lkml.kernel.org/r/20220927231823.718039222@goodmis.org

Cc: stable@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: 2c2b0a78b3739 ("ring-buffer: Add percentage of ring buffer full to wake up reader")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
kernel/trace/ring_buffer.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -662,7 +662,7 @@ int ring_buffer_wait(struct ring_buffer
nr_pages = cpu_buffer->nr_pages;
dirty = ring_buffer_nr_dirty_pages(buffer, cpu);
if (!cpu_buffer->shortest_full ||
- cpu_buffer->shortest_full < full)
+ cpu_buffer->shortest_full > full)
cpu_buffer->shortest_full = full;
raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
if (!pagebusy &&

\
 
 \ /
  Last update: 2022-10-24 18:59    [W:1.675 / U:0.520 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site