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    SubjectRe: [PATCH v4 3.0-rc2-tip 2/22] 2: uprobes: Breakground page replacement.
    * Peter Zijlstra <peterz@infradead.org> [2011-06-10 01:03:32]:

    > On Tue, 2011-06-07 at 18:28 +0530, Srikar Dronamraju wrote:
    > > +/**
    > > + * __replace_page - replace page in vma by new page.
    > > + * based on replace_page in mm/ksm.c
    > > + *
    > > + * @vma: vma that holds the pte pointing to page
    > > + * @page: the cowed page we are replacing by kpage
    > > + * @kpage: the modified page we replace page by
    > > + *
    > > + * Returns 0 on success, -EFAULT on failure.
    > > + */
    > > +static int __replace_page(struct vm_area_struct *vma, struct page *page,
    > > + struct page *kpage)
    >
    > This is a verbatim copy of mm/ksm.c:replace_page(), I think I can
    > remember why you did this, but the changelog utterly fails to mention
    > why we need a second copy of this logic (or anything much at all).
    >

    __replace_page is not exactly a copy of replace_page. Its a slightly
    modified copy of replace_page. Here are the reasons for having this
    modified copy instead of using the replace_page.

    replace_page was written specifically for ksm purpose by Hugh Dickins.
    Also Hugh said he doesnt like replace_page to be exposed for other uses.
    He has plans for further modifying replace_page for ksm specific
    purposes which might not be aligned to what we are using.

    Further for replace_page, its good enuf to call page_add_anon_rmap()
    However for uprobes needs we need to call page_add_new_anon_rmap().
    page_add_new_anon_rmap() will add the page to the right lru list.

    replace_page needs a reference to orig_pte while __replace_page doesnt
    need.

    I can add the same to Changelog but I am not sure it makes a good
    reading. Hence I had skipped it.

    --
    Thanks and Regards
    Srikar


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