From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-f199.google.com (mail-qt0-f199.google.com [209.85.216.199]) by kanga.kvack.org (Postfix) with ESMTP id 885E36B0313 for ; Fri, 16 Jun 2017 09:40:45 -0400 (EDT) Received: by mail-qt0-f199.google.com with SMTP id 20so35638110qtq.2 for ; Fri, 16 Jun 2017 06:40:45 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id g68si1058969qkd.163.2017.06.16.06.40.44 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 16 Jun 2017 06:40:44 -0700 (PDT) Date: Fri, 16 Jun 2017 15:40:41 +0200 From: Andrea Arcangeli Subject: Re: [PATCHv2 2/3] mm: Do not loose dirty and access bits in pmdp_invalidate() Message-ID: <20170616134041.GF11676@redhat.com> References: <20170615145224.66200-1-kirill.shutemov@linux.intel.com> <20170615145224.66200-3-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170615145224.66200-3-kirill.shutemov@linux.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" Cc: Andrew Morton , Vlastimil Babka , Vineet Gupta , Russell King , Will Deacon , Catalin Marinas , Ralf Baechle , "David S. Miller" , "Aneesh Kumar K . V" , Martin Schwidefsky , Heiko Carstens , linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org On Thu, Jun 15, 2017 at 05:52:23PM +0300, Kirill A. Shutemov wrote: > -void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address, > +pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address, > pmd_t *pmdp) > { > - pmd_t entry = *pmdp; > - set_pmd_at(vma->vm_mm, address, pmdp, pmd_mknotpresent(entry)); > - flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE); > + pmd_t old = pmdp_establish(pmdp, pmd_mknotpresent(*pmdp)); > + if (pmd_present(old)) > + flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE); > + return old; > } > #endif The pmd_present() check added above is superflous because there's no point to call pmdp_invalidate if the pmd is not present (present as in pmd_present) already. pmd_present returns true if _PAGE_PSE is set and it was always set before calling pmdp_invalidate. It looks like we could skip the flush if _PAGE_PRESENT is not set (i.e. for example if the pmd is PROTNONE) but that's not what the above pmd_present will do. -- 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