Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754368AbbDMNOg (ORCPT ); Mon, 13 Apr 2015 09:14:36 -0400 Received: from mta-out1.inet.fi ([62.71.2.227]:35055 "EHLO kirsi1.inet.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754201AbbDMNOf (ORCPT ); Mon, 13 Apr 2015 09:14:35 -0400 Date: Mon, 13 Apr 2015 16:13:57 +0300 From: "Kirill A. Shutemov" To: Laurent Dufour Cc: Andrew Morton , "Kirill A. Shutemov" , Hugh Dickins , Rik van Riel , Mel Gorman , Pavel Emelyanov , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Ingo Molnar , linuxppc-dev@lists.ozlabs.org, cov@codeaurora.org, criu@openvz.org Subject: Re: [RESEND PATCH v3 1/2] mm: Introducing arch_remap hook Message-ID: <20150413131357.GC12354@node.dhcp.inet.fi> References: <9d827fc618a718830b2c47aa87e8be546914c897.1428916945.git.ldufour@linux.vnet.ibm.com> <20150413115811.GA12354@node.dhcp.inet.fi> <552BB972.3010704@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <552BB972.3010704@linux.vnet.ibm.com> User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3330 Lines: 86 On Mon, Apr 13, 2015 at 02:41:22PM +0200, Laurent Dufour wrote: > On 13/04/2015 13:58, Kirill A. Shutemov wrote: > > On Mon, Apr 13, 2015 at 11:56:27AM +0200, Laurent Dufour wrote: > >> Some architecture would like to be triggered when a memory area is moved > >> through the mremap system call. > >> > >> This patch is introducing a new arch_remap mm hook which is placed in the > >> path of mremap, and is called before the old area is unmapped (and the > >> arch_unmap hook is called). > >> > >> The architectures which need to call this hook should define > >> __HAVE_ARCH_REMAP in their asm/mmu_context.h and provide the arch_remap > >> service with the following prototype: > >> void arch_remap(struct mm_struct *mm, > >> unsigned long old_start, unsigned long old_end, > >> unsigned long new_start, unsigned long new_end); > >> > >> Signed-off-by: Laurent Dufour > >> Reviewed-by: Ingo Molnar > >> --- > >> mm/mremap.c | 19 +++++++++++++------ > >> 1 file changed, 13 insertions(+), 6 deletions(-) > >> > >> diff --git a/mm/mremap.c b/mm/mremap.c > >> index 2dc44b1cb1df..009db5565893 100644 > >> --- a/mm/mremap.c > >> +++ b/mm/mremap.c > >> @@ -25,6 +25,7 @@ > >> > >> #include > >> #include > >> +#include > >> > >> #include "internal.h" > >> > >> @@ -286,13 +287,19 @@ static unsigned long move_vma(struct vm_area_struct *vma, > >> old_len = new_len; > >> old_addr = new_addr; > >> new_addr = -ENOMEM; > >> - } else if (vma->vm_file && vma->vm_file->f_op->mremap) { > >> - err = vma->vm_file->f_op->mremap(vma->vm_file, new_vma); > >> - if (err < 0) { > >> - move_page_tables(new_vma, new_addr, vma, old_addr, > >> - moved_len, true); > >> - return err; > >> + } else { > >> + if (vma->vm_file && vma->vm_file->f_op->mremap) { > >> + err = vma->vm_file->f_op->mremap(vma->vm_file, new_vma); > >> + if (err < 0) { > >> + move_page_tables(new_vma, new_addr, vma, > >> + old_addr, moved_len, true); > >> + return err; > >> + } > >> } > >> +#ifdef __HAVE_ARCH_REMAP > > > > It would be cleaner to provide dummy arch_remap() for !__HAVE_ARCH_REMAP > > in some generic header. > > The idea was to not impact all the architectures as arch_unmap(), > arch_dup_mmap() or arch_exit_mmap() implies. > > I look at the headers where such a dummy arch_remap could be put but I > can't figure out one which will not impact all the architecture. > What about defining a dummy service earlier in mm/remap.c in the case > __HAVE_ARCH_REMAP is not defined ? > Something like : > #ifndef __HAVE_ARCH_REMAP > static inline void void arch_remap(struct mm_struct *mm, > unsigned long old_start, > unsigned long old_end, > unsigned long new_start, > unsigned long new_end) > { > } > #endif Or just #define arch_remap(...) do { } while (0) -- Kirill A. Shutemov -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/