On 2017/5/25 22:19, Michal Hocko wrote:
> On Thu 25-05-17 21:48:56, zhong jiang wrote:
>> Hi Michal
>>
>> by a testcase, The patch is work as I think. The testcase is as follows.
>>
>> int main(void)
>> {
>> char *map;
>> int fd;
>>
>> fd = open("test", O_CREAT|O_RDWR);
>> unlink("test");
>> ftruncate(fd, 4096);
>> map = mmap(NULL, 4096, PROT_WRITE, MAP_PRIVATE, fd, 0);
>> map[0] = 11;
>> mlock(map, sizeof(fd));
> just a nit
> you probably wanted mlock(map, 4096)
>
>> ftruncate(fd, 0);
>> close(fd);
>> munlock(map, sizeof(fd));
> similarly here
>
>> munmap(map, 4096);
>>
>> return 0;
>> }
>>
>> before:
>> unevictable_pgs_mlocked 10589
>> unevictable_pgs_munlocked 10588
>> unevictable_pgs_cleared 1
>>
>> apply the patch;
>> after:
>> unevictable_pgs_mlocked 9497
>> unevictable_pgs_munlocked 9497
>> unevictable_pgs_cleared 1
> OK, this is definitely useful for the changelog.
>
>> unmap_mapping_range unmap them, page_remove_rmap will deal with
>> clear_page_mlock situation. we clear page Mlock flag and successful
>> isolate the page, the page will putback the evictable list. but it is not
>> record the munlock event.
> and this as well. I haven't checked that but it gives reviewers chance
> to understand your thinking much better so it is definitely useful.
> Mlock code is everything but straightforward.
>
HI, Michal
I will add the above info the chanelog. and resent it in v2.
Thanks
zhongjiang
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