Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932655AbbDMMln (ORCPT ); Mon, 13 Apr 2015 08:41:43 -0400 Received: from e06smtp17.uk.ibm.com ([195.75.94.113]:44174 "EHLO e06smtp17.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753910AbbDMMlh (ORCPT ); Mon, 13 Apr 2015 08:41:37 -0400 Message-ID: <552BB972.3010704@linux.vnet.ibm.com> Date: Mon, 13 Apr 2015 14:41:22 +0200 From: Laurent Dufour User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: "Kirill A. Shutemov" 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 References: <9d827fc618a718830b2c47aa87e8be546914c897.1428916945.git.ldufour@linux.vnet.ibm.com> <20150413115811.GA12354@node.dhcp.inet.fi> In-Reply-To: <20150413115811.GA12354@node.dhcp.inet.fi> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15041312-0029-0000-0000-0000042A8C9C Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3566 Lines: 108 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 > > >> + arch_remap(mm, old_addr, old_addr+old_len, >> + new_addr, new_addr+new_len); > > Spaces around '+'? Nice catch ;) Thanks, Laurent. > >> +#endif >> } >> >> /* Conceal VM_ACCOUNT so old reservation is not undone */ >> -- >> 1.9.1 >> >> -- >> 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/ > -- 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/