From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f173.google.com (mail-wi0-f173.google.com [209.85.212.173]) by kanga.kvack.org (Postfix) with ESMTP id C26096B0069 for ; Tue, 2 Dec 2014 09:57:01 -0500 (EST) Received: by mail-wi0-f173.google.com with SMTP id r20so28321851wiv.6 for ; Tue, 02 Dec 2014 06:57:01 -0800 (PST) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id yv4si35362764wjc.120.2014.12.02.06.56.58 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 02 Dec 2014 06:56:59 -0800 (PST) Message-ID: <547DD327.6070708@redhat.com> Date: Tue, 02 Dec 2014 09:56:39 -0500 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [PATCH v2 3/4] mm: refactor do_wp_page, extract the page copy flow References: <1417467491-20071-1-git-send-email-raindel@mellanox.com> <1417467491-20071-4-git-send-email-raindel@mellanox.com> <547D29A3.7090108@redhat.com> In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Shachar Raindel , "linux-mm@kvack.org" Cc: "kirill.shutemov@linux.intel.com" , "mgorman@suse.de" , "ak@linux.intel.com" , "matthew.r.wilcox@intel.com" , "dave.hansen@linux.intel.com" , "n-horiguchi@ah.jp.nec.com" , "akpm@linux-foundation.org" , "torvalds@linux-foundation.org" , Haggai Eran , "aarcange@redhat.com" , "pfeiner@google.com" , "hannes@cmpxchg.org" , Sagi Grimberg , "walken@google.com" , Jerome Glisse -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 12/02/2014 04:09 AM, Shachar Raindel wrote: >> I believe the mmu_notifier_invalidate_range_start & _end >> functions can be moved inside the pte_same(*page_table, >> orig_pte) branch. There is no reason to call those functions if >> we do not modify the page table entry. >> > > There is a critical reason for this - moving the MMU notifiers > there will make them unsleepable. This will prevent hardware > devices that keep secondary PTEs from waiting for an interrupt to > signal that the invalidation was completed. This is required for > example by the ODP patch set > (http://www.spinics.net/lists/linux-rdma/msg22044.html ) and by the > HMM patch set > (http://comments.gmane.org/gmane.linux.kernel.mm/116584 ). Ahhhh, that explains! Acked-by: Rik van Riel - -- All rights reversed -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQEcBAEBAgAGBQJUfdMnAAoJEM553pKExN6D6HQH/jYio5UBhlPhjp9XjWxwrDHy 7Pcf9nATYQhSN5IuxWp265yHMbFu9CwJefW2DLZLXbynImiy8rkl0HkaaDXEZnM4 ZizjCcxjgNVxD+F+EAsi/bj6kCtxNfmM0YxLCNHjOp835JQzQTbx94Joy1B10ba+ 42sTbGBArBVVuDOfHpiUMCj8HFiRT2BNwpfu44eDLAJQiTZIYU5OlXmWnSJQXDDF c648arGq75fyA8RHRZ/cTf0pztT+Gx5q/2LAxy+MkhiZjX9kXc1e98gWTOO70Qj+ IwP4YAfgScts+uqL2Q+EUVo0nBYAT1amyZft6j3aLQRrDcFhCkITk2VW0CdZHdE= =IA5v -----END PGP SIGNATURE----- -- 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