On 2019/10/17 8:49, Andrew Morton wrote: > On Wed, 16 Oct 2019 17:07:44 +0800 zhong jiang <zhongjiang@xxxxxxxxxx> wrote: > >>>> --- a/mm/gup.c~a >>>> +++ a/mm/gup.c >>>> @@ -1450,6 +1450,7 @@ static long check_and_migrate_cma_pages( >>>> bool drain_allow = true; >>>> bool migrate_allow = true; >>>> LIST_HEAD(cma_page_list); >>>> + long ret; >>>> check_again: >>>> for (i = 0; i < nr_pages;) { >>>> @@ -1511,17 +1512,18 @@ check_again: >>>> * again migrating any new CMA pages which we failed to isolate >>>> * earlier. >>>> */ >>>> - nr_pages = __get_user_pages_locked(tsk, mm, start, nr_pages, >>>> + ret = __get_user_pages_locked(tsk, mm, start, nr_pages, >>>> pages, vmas, NULL, >>>> gup_flags); >>>> - if ((nr_pages > 0) && migrate_allow) { >>>> + nr_pages = ret; >>>> + if (ret > 0 && migrate_allow) { >>>> drain_allow = true; >>>> goto check_again; >>>> } >>>> } >>>> - return nr_pages; >>>> + return ret; >>>> } >>>> #else >>>> static long check_and_migrate_cma_pages(struct task_struct *tsk, >>>> >>> +1 for this approach, please. >>> >>> >>> thanks, >> Hi, Andrew >> >> I didn't see the fix for the issue in the upstream. Your proposal should be >> appiled to upstream. Could you appiled the patch or repost by me ? > Forgotten about it ;) Please send a patch sometime? > > . > I will repost the patch as your suggestion. Thanks, Sincerely, zhong jiang