Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753750AbbFQWGK (ORCPT ); Wed, 17 Jun 2015 18:06:10 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:47452 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751001AbbFQWGG (ORCPT ); Wed, 17 Jun 2015 18:06:06 -0400 Message-ID: <5581EF1F.9000907@oracle.com> Date: Wed, 17 Jun 2015 15:05:19 -0700 From: Mike Kravetz User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Davidlohr Bueso CC: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Dave Hansen , Naoya Horiguchi , David Rientjes , Hugh Dickins , Aneesh Kumar , Hillf Danton , Christoph Hellwig Subject: Re: [RFC v4 PATCH 2/9] mm/hugetlb: expose hugetlb fault mutex for use by fallocate References: <1434056500-2434-1-git-send-email-mike.kravetz@oracle.com> <1434056500-2434-3-git-send-email-mike.kravetz@oracle.com> <1434062766.3165.103.camel@stgolabs.net> In-Reply-To: <1434062766.3165.103.camel@stgolabs.net> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1397 Lines: 32 On 06/11/2015 03:46 PM, Davidlohr Bueso wrote: > On Thu, 2015-06-11 at 14:01 -0700, Mike Kravetz wrote: >> /* Forward declaration */ >> static int hugetlb_acct_memory(struct hstate *h, long delta); >> @@ -3324,7 +3324,8 @@ static u32 fault_mutex_hash(struct hstate *h, struct mm_struct *mm, >> unsigned long key[2]; >> u32 hash; >> >> - if (vma->vm_flags & VM_SHARED) { >> + /* !vma implies this was called from hugetlbfs fallocate code */ >> + if (!vma || vma->vm_flags & VM_SHARED) { > > That !vma is icky, and really no need for it: hugetlbfs_fallocate(), for > example, already passes [pseudo]vma->vm_flags with VM_SHARED, and you > say it yourself in the comment. Do you see any reason why we cannot just > keep the vma->vm_flags & VM_SHARED check? > Ah, I did not recall all the users of this code until I went to change it. The other user is truncate_hugapages() which will now be used for fallocate hole punch. Truncate like fallocate is an inode operation and there is no specific vma. I can create a pseudo-vma here as well just to pass the flag. I guess that would at least be consistent with the other user. -- Mike Kravetz -- 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/