Messages in this thread | ![/](/images/icornerl.gif) | | Date | Tue, 25 Aug 2009 13:46:19 +0900 | Subject | Re: [PATCH] mm: make munlock fast when mlock is canceled by sigkill | From | Hiroaki Wakabayashi <> |
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Thank you for reviews.
>>> > @@ -254,6 +254,7 @@ static inline void >>> > mminit_validate_memmodel_limits(unsigned long *start_pfn, >>> > #define GUP_FLAGS_FORCE 0x2 >>> > #define GUP_FLAGS_IGNORE_VMA_PERMISSIONS 0x4 >>> > #define GUP_FLAGS_IGNORE_SIGKILL 0x8 >>> > +#define GUP_FLAGS_ALLOW_NULL 0x10 >>> > >>> >>> I am worried about adding new flag whenever we need it. >>> But I think this case makes sense to me. >>> In addition, I guess ZERO page can also use this flag. >>> >>> Kame. What do you think about it? >>> >> I do welcome this ! >> Then, I don't have to take care of mlock/munlock in ZERO_PAGE patch. >> >> And without this patch, munlock() does copy-on-write just for unpinning memory. >> So, this patch shows some right direction, I think. >> >> One concern is flag name, ALLOW_NULL sounds not very good. >> >> GUP_FLAGS_NOFAULT ? >> >> I wonder we can remove a hack of FOLL_ANON for core-dump by this flag, too. > > Yeah, GUP_FLAGS_NOFAULT is better.
Me too. I will change this flag name.
> Plus, this patch change __get_user_pages() return value meaning IOW. > after this patch, it can return following value, > > return value: 3 > pages[0]: hoge-page > pages[1]: null > pages[2]: fuga-page > > but, it can be > > return value: 2 > pages[0]: hoge-page > pages[1]: fuga-page > > no?
I did misunderstand mean of get_user_pages()'s return value.
When I try to change __get_user_pages(), I got problem. If remove NULLs from pages, __mlock_vma_pages_range() cannot know how long __get_user_pages() readed. So, I have to get the virtual address of the page from vma and page. Because __mlock_vma_pages_range() have to call __get_user_pages() many times with different `start' argument.
I try to use page_address_in_vma(), but it failed. (page_address_in_vma() returned -EFAULT) I cannot find way to solve this problem. Are there good ideas? Please give me some ideas.
Thanks. -- Hiroaki Wakabayashi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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