[PATCH] makedumpfile: Fix a bug when multi-threads feature meets enospace

[Zhou Wenjian]

Hi Tachibana,

Thanks for your reply.

And I do appreciate Kumagai-san's help these years.


On 02/16/2018 10:45 AM, Masaki Tachibana wrote:
> Hi,
>
> Atsushi Kumagai has retired, so other members will maintain makedumpfile.
>
>
> Wenjian
>
> Sorry for the late reply.
> Your patch looks good to me.
> I'll merge it into V1.6.4.
>
> Thanks
> tachibana
>
>
>> -----Original Message-----
>> From: kexec [mailto:kexec-bounces at lists.infradead.org] On Behalf Of Zhou Wenjian
>> Sent: Thursday, February 08, 2018 8:53 PM
>> To: kexec at lists.infradead.org
>> Cc: Kumagai Atsushi() <ats-kumagai at wm.jp.nec.com>; Suzuki Keiichirou() <kei-suzuki at xr.jp.nec.com>
>> Subject: Re: [PATCH] makedumpfile: Fix a bug when multi-threads feature meets enospace
>>
>> ping...
>>
>>
>> On 01/29/2018 08:54 PM, Zhou Wenjian wrote:
>>> Currently, when multi-threads feature meets enospace error,
>>> the main thread will call pthread_join(). However, there is one
>>> thread doing while{} and won't stop.
>>>
>>>                   pthread_mutex_lock(&info->page_data_mutex);
>>>                   while (page_data_buf[index].used != FALSE) {
>>>                           index = (index + 1) % info->num_buffers;
>>>                   }
>>>                   page_data_buf[index].used = TRUE;
>>>                   pthread_mutex_unlock(&info->page_data_mutex);
>>>
>>> Then makedumpfile hangs.
>>>
>>> This patch add a cancel point in while{}.
>>>
>>> Signed-off-by: Zhou Wenjian <zhouwj.fi at gmail.com>
>>> ---
>>>    makedumpfile.c | 4 +++-
>>>    1 file changed, 3 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/makedumpfile.c b/makedumpfile.c
>>> index ed138d3..f7ad50c 100644
>>> --- a/makedumpfile.c
>>> +++ b/makedumpfile.c
>>> @@ -7731,11 +7731,13 @@ kdump_thread_function_cyclic(void *arg) {
>>>    		buf_ready = FALSE;
>>>
>>>    		pthread_mutex_lock(&info->page_data_mutex);
>>> +		pthread_cleanup_push(pthread_mutex_unlock, &info->page_data_mutex);
>>>    		while (page_data_buf[index].used != FALSE) {
>>> +			pthread_testcancel();
>>>    			index = (index + 1) % info->num_buffers;
>>>    		}
>>>    		page_data_buf[index].used = TRUE;
>>> -		pthread_mutex_unlock(&info->page_data_mutex);
>>> +		pthread_cleanup_pop(1);
>>>
>>>    		while (buf_ready == FALSE) {
>>>    			pthread_testcancel();
>> --
>> Thanks
>> Zhou
>>
>>
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-- 
Thanks
Zhou