On Sat, 10 Jan 2015 02:41:43 +0200 "Kirill A. Shutemov" <kirill@xxxxxxxxxxxxx> wrote:
> On Fri, Jan 09, 2015 at 04:24:19PM -0800, Andrew Morton wrote:
> > On Thu, 8 Jan 2015 16:10:04 +0200 (EET) "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> wrote:
> >
> > > Something like this?
> > >
> > > >From 5fd481c1c521112e9cea407f5a2644c9f93d0e14 Mon Sep 17 00:00:00 2001
> > > From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
> > > Date: Thu, 8 Jan 2015 15:59:23 +0200
> > > Subject: [PATCH] mm: more checks on free_pages_prepare() for tail pages
> > >
> > > Apart form being dead, destroy_compound_page() did some potentially
> > > useful checks. Let's re-introduce them in free_pages_prepare(), where
> > > they can be acctually triggered.
> > >
> > > compound_order() assert is already in free_pages_prepare(). We have few
> > > checks for tail pages left.
> > >
> >
> > I'm thinking we avoid the overhead unless CONFIG_DEBUG_VM?
>
> That's why there's "if (!IS_ENABLED(CONFIG_DEBUG_VM))". Is it wrong in
> some way?
> I didn't check, but I assume compiler is smart enough to get rid of
> free_tail_pages_check() if CONFIG_DEBUG_VM is not defined. No?
doh, OK. I updated the
mm-more-checks-on-free_pages_prepare-for-tail-pages.patch changelog to
reflect this and did
--- a/mm/page_alloc.c~mm-more-checks-on-free_pages_prepare-for-tail-pages-fix
+++ a/mm/page_alloc.c
@@ -764,19 +764,18 @@ static void free_one_page(struct zone *z
spin_unlock(&zone->lock);
}
-static int free_tail_pages_check(struct page *head_page, struct page *page)
+static void free_tail_pages_check(struct page *head_page, struct page *page)
{
if (!IS_ENABLED(CONFIG_DEBUG_VM))
- return 0;
+ return;
if (unlikely(!PageTail(page))) {
bad_page(page, "PageTail not set", 0);
- return 1;
+ return;
}
if (unlikely(page->first_page != head_page)) {
bad_page(page, "first_page not consistent", 0);
- return 1;
+ return;
}
- return 0;
}
static bool free_pages_prepare(struct page *page, unsigned int order)
_
--
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>