From mboxrd@z Thu Jan 1 00:00:00 1970 From: Olaf Hering Subject: Re: [PATCH 6 of 8] x86/mm: Properly account for paged out pages Date: Thu, 26 Jan 2012 10:54:01 +0100 Message-ID: <20120126095401.GC21629@aepfle.de> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Andres Lagar-Cavilla Cc: andres@gridcentric.ca, xen-devel@lists.xensource.com, tim@xen.org, adin@gridcentric.ca List-Id: xen-devel@lists.xenproject.org On Wed, Jan 25, Andres Lagar-Cavilla wrote: > xen/arch/x86/mm/p2m.c | 3 ++- > 1 files changed, 2 insertions(+), 1 deletions(-) > > > If we hit the page after nominate but before paging it out, don't decrement the > domain count of paged out pages. The meaning of paged_pages is to track released pages. In p2m_mem_paging_evict() it gets incremented once the page is removed from the domain, and in p2m_mem_paging_prep() it should be decremented right after the alloc_domheap_page() call. So the patch should move the atomic_dec() call after successful page allocation. Olaf > diff -r c41436e555cd -r d4336e35f0bc xen/arch/x86/mm/p2m.c > --- a/xen/arch/x86/mm/p2m.c > +++ b/xen/arch/x86/mm/p2m.c > @@ -1041,7 +1041,8 @@ int p2m_mem_paging_prep(struct domain *d > p2m_ram_rw, a); > set_gpfn_from_mfn(mfn_x(mfn), gfn); > > - atomic_dec(&d->paged_pages); > + if ( !page_extant ) > + atomic_dec(&d->paged_pages); > > ret = 0; >