From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boaz Harrosh Subject: Re: [PATCH 1/3] mm(v4.1): New pfn_mkwrite same as page_mkwrite for VM_PFNMAP Date: Tue, 07 Apr 2015 12:22:42 +0300 Message-ID: <5523A1E2.6080704@plexistor.com> References: <55239645.9000507@plexistor.com> <552397E6.5030506@plexistor.com> <20150407090335.GA12664@node.dhcp.inet.fi> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: Dave Chinner , Matthew Wilcox , Andrew Morton , "Kirill A. Shutemov" , Jan Kara , Hugh Dickins , Mel Gorman , linux-mm@kvack.org, linux-nvdimm , linux-fsdevel , Eryu Guan , Christoph Hellwig , Stable Tree To: "Kirill A. Shutemov" Return-path: In-Reply-To: <20150407090335.GA12664@node.dhcp.inet.fi> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org On 04/07/2015 12:03 PM, Kirill A. Shutemov wrote: > On Tue, Apr 07, 2015 at 11:40:06AM +0300, Boaz Harrosh wrote: >> >> [v2] >> Based on linux-next/akpm [3dc4623]. For v4.1 merge window >> Incorporated comments from Andrew And Kirill > > Not really. You've ignored most of them. See below. > Yes sorry about that I sent the wrong version. <> >> --- >> include/linux/mm.h | 3 +++ >> mm/memory.c | 35 +++++++++++++++++++++++++++++++---- > > Please, document it in Documentation/filesystems/Locking. > Ha, I missed this one. Ok will try to put something coherent. <> >> diff --git a/mm/memory.c b/mm/memory.c >> index 59f6268..6e8f3f6 100644 >> --- a/mm/memory.c >> +++ b/mm/memory.c >> @@ -1982,6 +1982,19 @@ static int do_page_mkwrite(struct vm_area_struct *vma, struct page *page, >> return ret; >> } >> >> +static int do_pfn_mkwrite(struct vm_area_struct *vma, unsigned long address) >> +{ >> + struct vm_fault vmf = { >> + .page = 0, > > .page = NULL, > >> + .pgoff = (((address & PAGE_MASK) - vma->vm_start) >> + >> PAGE_SHIFT) + vma->vm_pgoff, > > .pgoff = linear_page_index(vma, address), > Yes I had fixes for these two >> + .virtual_address = (void __user *)(address & PAGE_MASK), >> + .flags = FAULT_FLAG_WRITE | FAULT_FLAG_MKWRITE, >> + }; >> + >> + return vma->vm_ops->pfn_mkwrite(vma, &vmf); >> +} >> + >> /* >> * Handle write page faults for pages that can be reused in the current vma >> * >> @@ -2259,14 +2272,28 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, >> * VM_PFNMAP VMA. >> * >> * We should not cow pages in a shared writeable mapping. >> - * Just mark the pages writable as we can't do any dirty >> - * accounting on raw pfn maps. >> + * Just mark the pages writable and/or call ops->pfn_mkwrite. >> */ >> if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) == >> - (VM_WRITE|VM_SHARED)) >> + (VM_WRITE|VM_SHARED)) { > > Let's move this case in separate function -- wp_pfn_shared(). As we do for > wp_page_shared(). > Ha, OK I will try that. I will need to re-run tests to make sure I did not mess up Thanks will fix, makes sense Boaz >> + if (vma->vm_ops && vma->vm_ops->pfn_mkwrite) { >> + int ret; >> + >> + pte_unmap_unlock(page_table, ptl); >> + ret = do_pfn_mkwrite(vma, address); >> + if (ret & VM_FAULT_ERROR) >> + return ret; >> + page_table = pte_offset_map_lock(mm, pmd, >> + address, &ptl); >> + /* Did pfn_mkwrite already fixed up the pte */ >> + if (!pte_same(*page_table, orig_pte)) { >> + pte_unmap_unlock(page_table, ptl); >> + return ret; >> + } >> + } >> return wp_page_reuse(mm, vma, address, page_table, ptl, >> orig_pte, old_page, 0, 0); >> - >> + } >> pte_unmap_unlock(page_table, ptl); >> return wp_page_copy(mm, vma, address, page_table, pmd, >> orig_pte, old_page); -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org