From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f50.google.com (mail-pa0-f50.google.com [209.85.220.50]) by kanga.kvack.org (Postfix) with ESMTP id 091B482997 for ; Fri, 22 May 2015 02:26:35 -0400 (EDT) Received: by paza2 with SMTP id a2so2299075paz.3 for ; Thu, 21 May 2015 23:26:34 -0700 (PDT) Received: from tyo201.gate.nec.co.jp (TYO201.gate.nec.co.jp. [210.143.35.51]) by mx.google.com with ESMTPS id cn10si1909191pac.193.2015.05.21.23.26.33 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Thu, 21 May 2015 23:26:34 -0700 (PDT) From: Naoya Horiguchi Subject: Re: [RFC v3 PATCH 04/10] mm/hugetlb: expose hugetlb fault mutex for use by fallocate Date: Fri, 22 May 2015 06:23:45 +0000 Message-ID: <20150522062344.GB21526@hori1.linux.bs1.fc.nec.co.jp> References: <1432223264-4414-1-git-send-email-mike.kravetz@oracle.com> <1432223264-4414-5-git-send-email-mike.kravetz@oracle.com> In-Reply-To: <1432223264-4414-5-git-send-email-mike.kravetz@oracle.com> Content-Language: ja-JP Content-Type: text/plain; charset="iso-2022-jp" Content-ID: <6BFE24611483ED4C88169D16B37842D9@gisp.nec.co.jp> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: Mike Kravetz Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Dave Hansen , David Rientjes , Hugh Dickins , Davidlohr Bueso , Aneesh Kumar , Hillf Danton , Christoph Hellwig On Thu, May 21, 2015 at 08:47:38AM -0700, Mike Kravetz wrote: > hugetlb page faults are currently synchronized by the table of > mutexes (htlb_fault_mutex_table). fallocate code will need to > synchronize with the page fault code when it allocates or > deletes pages. Expose interfaces so that fallocate operations > can be synchronized with page faults. >=20 > Signed-off-by: Mike Kravetz > --- > include/linux/hugetlb.h | 3 +++ > mm/hugetlb.c | 23 ++++++++++++++++++++++- > 2 files changed, 25 insertions(+), 1 deletion(-) >=20 > diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h > index fd337f2..d0d033e 100644 > --- a/include/linux/hugetlb.h > +++ b/include/linux/hugetlb.h > @@ -82,6 +82,9 @@ void putback_active_hugepage(struct page *page); > bool is_hugepage_active(struct page *page); > void free_huge_page(struct page *page); > void hugetlb_fix_reserve_counts(struct inode *inode, bool restore_reserv= e); > +u32 hugetlb_fault_mutex_shared_hash(struct address_space *mapping, pgoff= _t idx); > +void hugetlb_fault_mutex_lock(u32 hash); > +void hugetlb_fault_mutex_unlock(u32 hash); > =20 > #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE > pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *p= ud); > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 620cc9e..df0d32a 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -3183,7 +3183,8 @@ static u32 fault_mutex_hash(struct hstate *h, struc= t mm_struct *mm, > unsigned long key[2]; > u32 hash; > =20 > - if (vma->vm_flags & VM_SHARED) { > + /* !vma implies this was called from hugetlbfs fallocate code */ > + if (!vma || vma->vm_flags & VM_SHARED) { > key[0] =3D (unsigned long) mapping; > key[1] =3D idx; > } else { > @@ -3209,6 +3210,26 @@ static u32 fault_mutex_hash(struct hstate *h, stru= ct mm_struct *mm, > } > #endif > =20 > +/* > + * Interfaces to the fault mutex routines for use by hugetlbfs > + * fallocate code. Faults must be synchronized with page adds or > + * deletes by fallocate. fallocate only deals with shared mappings. > + */ > +u32 hugetlb_fault_mutex_shared_hash(struct address_space *mapping, pgoff= _t idx) > +{ > + return fault_mutex_hash(NULL, NULL, NULL, mapping, idx, 0); > +} > + > +void hugetlb_fault_mutex_lock(u32 hash) > +{ > + mutex_lock(&htlb_fault_mutex_table[hash]); > +} > + > +void hugetlb_fault_mutex_unlock(u32 hash) > +{ > + mutex_unlock(&htlb_fault_mutex_table[hash]); > +} > + > int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, > unsigned long address, unsigned int flags) > { You introduce new lock/unlock interfaces, so how about making the existing user of this lock (i.e. hugetlb_fault()) use them? Thanks, Naoya Horiguchi= -- 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