Re: fix iounmap and a pageattr memleak (x86 and x86-64)

Andrew Morton
2004-11-02T23:04:26Z

Dave Hansen <haveblue@us.ibm.com> wrote:
>
> Andrea Arcangeli wrote:
> > Still I recommend investigating _why_ debug_pagealloc is violating the
> > API. It might not be necessary to wait for the pageattr universal
> > feature to make DEBUG_PAGEALLOC work safe.
>
> This makes the DEBUG_PAGEALLOC stuff symmetric enough to boot for me,
> and it's pretty damn simple. Any ideas for doing this without bloating
> 'struct page', even in the debugging case?

You could use a bit from page->flags. But CONFIG_DEBUG_PAGEALLOC uses so
much additional memory nobody would notice anyway.

hm. Or maybe page->mapcount is available on these pages.