> On Oct 27, 2015, at 15:09, Minchan Kim <minchan@xxxxxxxxxx> wrote: > > Hello Yalin, > > Sorry for missing you in Cc list. > IIRC, mails to send your previous mail address(Yalin.Wang@xxxxxxxxxxxxxx) > were returned. > > You added comment bottom line so I'm not sure what PageDirty you meant. > >> it is wrong here if you only check PageDirty() to decide if the page is freezable or not . >> The Anon page are shared by multiple process, _mapcount > 1 , >> so you must check all pt_dirty bit during page_referenced() function, >> see this mail thread: >> http://ns1.ske-art.com/lists/kernel/msg1934021.html > > If one of pte among process sharing the page was dirty, the dirtiness should > be propagated from pte to PG_dirty by try_to_unmap_one. > IOW, if the page doesn't have PG_dirty flag, it means all of process did > MADV_FREE. > > Am I missing something from you question? > If so, could you show exact scenario I am missing? > > Thanks for the interest. oh, yeah , that is right , i miss that , pte_dirty will propagate to PG_dirty , so that is correct . Generic to say this patch move set_page_dirty() from add_to_swap() to try_to_unmap(), i think can change a little about this patch: @@ -1476,6 +1446,8 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma, ret = SWAP_FAIL; goto out_unmap; } + if (!PageDirty(page)) + SetPageDirty(page); if (list_empty(&mm->mmlist)) { spin_lock(&mmlist_lock); if (list_empty(&mm->mmlist)) i think this 2 lines can be removed , since pte_dirty have propagated to set_page_dirty() , we don’t need this line here , otherwise you will always dirty a AnonPage, even it is clean, then we will page out this clean page to swap partition one more , this is not needed. am i understanding correctly ? By the way, please change my mail address to yalin.wang2010@xxxxxxxxx in CC list . Thanks a lot. :) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href