From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44828) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Xa6Le-0001OF-IX for qemu-devel@nongnu.org; Fri, 03 Oct 2014 13:09:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Xa6LX-0005mH-6m for qemu-devel@nongnu.org; Fri, 03 Oct 2014 13:08:54 -0400 Received: from mx1.redhat.com ([209.132.183.28]:31679) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Xa6LW-0005mB-Vd for qemu-devel@nongnu.org; Fri, 03 Oct 2014 13:08:47 -0400 From: Andrea Arcangeli Date: Fri, 3 Oct 2014 19:07:51 +0200 Message-Id: <1412356087-16115-2-git-send-email-aarcange@redhat.com> In-Reply-To: <1412356087-16115-1-git-send-email-aarcange@redhat.com> References: <1412356087-16115-1-git-send-email-aarcange@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PATCH 01/17] mm: gup: add FOLL_TRIED List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-api@vger.kernel.org Cc: Robert Love , Dave Hansen , Jan Kara , Neil Brown , Stefan Hajnoczi , Andrew Jones , KOSAKI Motohiro , Michel Lespinasse , Taras Glek , Juan Quintela , Hugh Dickins , Isaku Yamahata , Mel Gorman , Sasha Levin , Android Kernel Team , "\\\"Dr. David Alan Gilbert\\\"" , "Huangpeng (Peter)" , Andres Lagar-Cavilla , Christopher Covington , Anthony Liguori , Paolo Bonzini , Keith Packard , Wenchao Xia , Andy Lutomirski , Minchan Kim , Dmitry Adamushko , Johannes Weiner , Mike Hommey , Andrew Morton , Linus Torvalds , Peter Feiner From: Andres Lagar-Cavilla Reviewed-by: Radim Kr=C4=8Dm=C3=A1=C5=99 Signed-off-by: Andres Lagar-Cavilla Signed-off-by: Andrea Arcangeli --- include/linux/mm.h | 1 + mm/gup.c | 4 ++++ 2 files changed, 5 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index 8981cc8..0f4196a 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1985,6 +1985,7 @@ static inline struct page *follow_page(struct vm_ar= ea_struct *vma, #define FOLL_HWPOISON 0x100 /* check page is hwpoisoned */ #define FOLL_NUMA 0x200 /* force NUMA hinting page fault */ #define FOLL_MIGRATION 0x400 /* wait for page to replace migration entry= */ +#define FOLL_TRIED 0x800 /* a retry, previous pass started an IO */ =20 typedef int (*pte_fn_t)(pte_t *pte, pgtable_t token, unsigned long addr, void *data); diff --git a/mm/gup.c b/mm/gup.c index 91d044b..af7ea3e 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -281,6 +281,10 @@ static int faultin_page(struct task_struct *tsk, str= uct vm_area_struct *vma, fault_flags |=3D FAULT_FLAG_ALLOW_RETRY; if (*flags & FOLL_NOWAIT) fault_flags |=3D FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT; + if (*flags & FOLL_TRIED) { + VM_WARN_ON_ONCE(fault_flags & FAULT_FLAG_ALLOW_RETRY); + fault_flags |=3D FAULT_FLAG_TRIED; + } =20 ret =3D handle_mm_fault(mm, vma, address, fault_flags); if (ret & VM_FAULT_ERROR) {