Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756838Ab3GYRa3 (ORCPT ); Thu, 25 Jul 2013 13:30:29 -0400 Received: from www.sr71.net ([198.145.64.142]:35798 "EHLO blackbird.sr71.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756678Ab3GYRaZ (ORCPT ); Thu, 25 Jul 2013 13:30:25 -0400 Message-ID: <51F160A5.2040004@sr71.net> Date: Thu, 25 Jul 2013 10:30:13 -0700 From: Dave Hansen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130623 Thunderbird/17.0.7 MIME-Version: 1.0 To: Robert Jennings CC: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Alexander Viro , Rik van Riel , Andrea Arcangeli , Matt Helsley , Anthony Liguori , Michael Roth , Lei Li , Leonardo Garcia Subject: Re: [RFC PATCH 1/2] vmsplice unmap gifted pages for recipient References: <1374772906-21511-1-git-send-email-rcj@linux.vnet.ibm.com> <1374772906-21511-2-git-send-email-rcj@linux.vnet.ibm.com> In-Reply-To: <1374772906-21511-2-git-send-email-rcj@linux.vnet.ibm.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1470 Lines: 40 On 07/25/2013 10:21 AM, Robert Jennings wrote: > +static void zap_buf_page(unsigned long useraddr) > +{ > + struct vm_area_struct *vma; > + > + down_read(¤t->mm->mmap_sem); > + vma = find_vma_intersection(current->mm, useraddr, > + useraddr + PAGE_SIZE); > + if (!IS_ERR_OR_NULL(vma)) > + zap_page_range(vma, useraddr, PAGE_SIZE, NULL); > + up_read(¤t->mm->mmap_sem); > +} > + > /** > * splice_to_pipe - fill passed data into a pipe > * @pipe: pipe to fill > @@ -212,8 +224,16 @@ ssize_t splice_to_pipe(struct pipe_inode_info *pipe, > buf->len = spd->partial[page_nr].len; > buf->private = spd->partial[page_nr].private; > buf->ops = spd->ops; > - if (spd->flags & SPLICE_F_GIFT) > + if (spd->flags & SPLICE_F_GIFT) { > + unsigned long useraddr = > + spd->partial[page_nr].useraddr; > + > + if ((spd->flags & SPLICE_F_MOVE) && > + !buf->offset && (buf->len == PAGE_SIZE)) > + /* Can move page aligned buf */ > + zap_buf_page(useraddr); > buf->flags |= PIPE_BUF_FLAG_GIFT; > + } There isn't quite enough context here, but is it going to do this zap_buf_page() very often? Seems a bit wasteful to do the up/down and find_vma() every trip through the loop. -- 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/