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commit b22be68453b2497e86cbd273b9cd56fadc5859e3
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Author: Ying Lv <lvying6@huawei.com>
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Date:   Wed May 15 11:15:42 2019 +0800
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    fix rasdaemon high CPU usage when part of CPUs offline
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    When we set part of CPU core offline, such as by setting the kernel cmdline
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    maxcpus = N(N is less than the total number of system CPU cores).
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    And then, we will observe that the CPU usage of some rasdaemon threads
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    is very close to 100.
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    This is because when part of CPU offline, poll in read_ras_event_all_cpus func
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    will fallback to pthread way.
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    Offlined CPU thread will return negative value when read trace_pipe_raw,
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    negative return value will covert to positive value because of 'unsigned size'.
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    So code will always go into 'size > 0' branch, and the CPU usage is too high.
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    Here, variable size uses int type will go to the right branch.
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    Fiexs: eff7c9e0("ras-events: Only use pthreads for collect if poll() not available")
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    Reported-by: Zhipeng Xie <xiezhipeng1@huawei.com>
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    Signed-off-by: Ying Lv <lvying6@huawei.com>
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    Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
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diff --git a/ras-events.c b/ras-events.c
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index 4e7b815..38ebe1e 100644
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--- a/ras-events.c
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+++ b/ras-events.c
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@@ -426,7 +426,7 @@ static int read_ras_event(int fd,
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 			  struct kbuffer *kbuf,
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 			  void *page)
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 {
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-	unsigned size;
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+	int size;
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 	unsigned long long time_stamp;
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 	void *data;
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