Messages in this thread | | | From | Song Liu <> | Subject | Re: + uprobe-use-original-page-when-all-uprobes-are-removed.patch added to -mm tree | Date | Mon, 29 Jul 2019 17:04:05 +0000 |
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> On Jul 29, 2019, at 8:05 AM, Oleg Nesterov <oleg@redhat.com> wrote: > > I didn't see this version, so let me reply here. > > On 07/26, Andrew Morton wrote: >> >> + /* try orig_page only for unregister and anonymous old_page */ >> + if (!is_register && PageAnon(old_page)) { > > Well, this is confusing... nothing really wrong, but we certainly do not > want to install the new anonymous page if !is_register && !PageAnon(old). > And in this case we do not even want to call __replace page(). > > OK, I won't insist, this should almost never happen, but again, please > see https://lore.kernel.org/lkml/20190726084423.GA16112@redhat.com/
I see. Do you want me fold this patch with 2/4?
> >> + struct page *orig_page; >> + pgoff_t index; >> + >> + index = vaddr_to_offset(vma, vaddr & PAGE_MASK) >> PAGE_SHIFT; >> + orig_page = find_get_page(vma->vm_file->f_inode->i_mapping, >> + index); >> + >> + if (orig_page) { >> + if (PageUptodate(orig_page) && >> + pages_identical(new_page, orig_page)) { >> + /* let go new_page */ >> + put_page(new_page); >> + new_page = NULL; >> + >> + /* dec_mm_counter for old_page */ >> + dec_mm_counter(mm, MM_ANONPAGES); > > this assumes that __replace_page() can't fail, but it can. I think you > should move this into into __replace_page().
Good catch! Let me fix it.
Hi Andrew,
Do you prefer a whole v10 (1/4 to 4/4) or just newer version of this one (2/4)?
Thanks, Song
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