On Tue, Oct 20, 2015 at 04:21:09PM +0900, Minchan Kim wrote: > On Mon, Oct 19, 2015 at 07:01:50PM +0900, Minchan Kim wrote: > > On Mon, Oct 19, 2015 at 03:31:42PM +0900, Minchan Kim wrote: > > > Hello, it's too late since I sent previos patch. > > > https://lkml.org/lkml/2015/6/3/37 > > > > > > This patch is alomost new compared to previos approach. > > > I think this is more simple, clear and easy to review. > > > > > > One thing I should notice is that I have tested this patch > > > and couldn't find any critical problem so I rebased patchset > > > onto recent mmotm(ie, mmotm-2015-10-15-15-20) to send formal > > > patchset. Unfortunately, I start to see sudden discarding of > > > the page we shouldn't do. IOW, application's valid anonymous page > > > was disappeared suddenly. > > > > > > When I look through THP changes, I think we could lose > > > dirty bit of pte between freeze_page and unfreeze_page > > > when we mark it as migration entry and restore it. > > > So, I added below simple code without enough considering > > > and cannot see the problem any more. > > > I hope it's good hint to find right fix this problem. > > > > > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > > > index d5ea516ffb54..e881c04f5950 100644 > > > --- a/mm/huge_memory.c > > > +++ b/mm/huge_memory.c > > > @@ -3138,6 +3138,9 @@ static void unfreeze_page_vma(struct vm_area_struct *vma, struct page *page, > > > if (is_write_migration_entry(swp_entry)) > > > entry = maybe_mkwrite(entry, vma); > > > > > > + if (PageDirty(page)) > > > + SetPageDirty(page); > > > > The condition of PageDirty was typo. I didn't add the condition. > > Just added. > > > > SetPageDirty(page); > > I reviewed THP refcount redesign patch and It seems below patch fixes > MADV_FREE problem. It works well for hours. > > From 104a0940b4c0f97e61de9fee0fd602926ff28312 Mon Sep 17 00:00:00 2001 > From: Minchan Kim <minchan@xxxxxxxxxx> > Date: Tue, 20 Oct 2015 16:00:52 +0900 > Subject: [PATCH] mm: mark head page dirty in split_huge_page > > In thp split in old THP refcount, we mappped all of pages > (ie, head + tails) to pte_mkdirty and mark PG_flags to every > tail pages. > > But with THP refcount redesign, we can lose dirty bit in page table > and PG_dirty for head page if we want to free the THP page using typo. freeze -- 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=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>