From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E358BC3A589 for ; Sun, 18 Aug 2019 18:26:32 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8DE212086C for ; Sun, 18 Aug 2019 18:26:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8DE212086C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=hpe.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 2C2A36B0007; Sun, 18 Aug 2019 14:26:32 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2726D6B000A; Sun, 18 Aug 2019 14:26:32 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 13B8C6B000C; Sun, 18 Aug 2019 14:26:32 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0157.hostedemail.com [216.40.44.157]) by kanga.kvack.org (Postfix) with ESMTP id E2CEA6B0007 for ; Sun, 18 Aug 2019 14:26:31 -0400 (EDT) Received: from smtpin10.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id 4A882181AC9AE for ; Sun, 18 Aug 2019 18:26:31 +0000 (UTC) X-FDA: 75836378982.10.can18_7304db175374f X-HE-Tag: can18_7304db175374f X-Filterd-Recvd-Size: 9673 Received: from mx0a-002e3701.pphosted.com (mx0a-002e3701.pphosted.com [148.163.147.86]) by imf37.hostedemail.com (Postfix) with ESMTP for ; Sun, 18 Aug 2019 18:26:30 +0000 (UTC) Received: from pps.filterd (m0134420.ppops.net [127.0.0.1]) by mx0b-002e3701.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x7IILjcL028863; Sun, 18 Aug 2019 18:26:24 GMT Received: from g4t3427.houston.hpe.com (g4t3427.houston.hpe.com [15.241.140.73]) by mx0b-002e3701.pphosted.com with ESMTP id 2ueuc7b3md-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 18 Aug 2019 18:26:24 +0000 Received: from g9t2301.houston.hpecorp.net (g9t2301.houston.hpecorp.net [16.220.97.129]) by g4t3427.houston.hpe.com (Postfix) with ESMTP id 5E5475C; Sun, 18 Aug 2019 18:26:00 +0000 (UTC) Received: from hpe.com (teo-eag.americas.hpqcorp.net [10.33.152.10]) by g9t2301.houston.hpecorp.net (Postfix) with ESMTP id 9C4F64B; Sun, 18 Aug 2019 18:25:59 +0000 (UTC) Date: Sun, 18 Aug 2019 13:25:59 -0500 From: Dimitri Sivanich To: Bharath Vedartham Cc: jhubbard@nvidia.com, gregkh@linuxfoundation.org, sivanich@hpe.com, arnd@arndb.de, ira.weiny@intel.com, jglisse@redhat.com, william.kucharski@oracle.com, hch@lst.de, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-kernel-mentees@lists.linuxfoundation.org Subject: Re: [Linux-kernel-mentees][PATCH v5 1/1] sgi-gru: Remove *pte_lookup functions, Convert to get_user_page*() Message-ID: <20190818182559.GA5062@hpe.com> References: <1565379497-29266-1-git-send-email-linux.bhar@gmail.com> <1565379497-29266-2-git-send-email-linux.bhar@gmail.com> <20190818175824.GA6635@bharath12345-Inspiron-5559> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20190818175824.GA6635@bharath12345-Inspiron-5559> User-Agent: Mutt/1.5.24 (2015-08-30) X-HPE-SCL: -1 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-08-18_08:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=2 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1908180202 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Yes it will. On Sun, Aug 18, 2019 at 11:28:24PM +0530, Bharath Vedartham wrote: > Hi Dimitri, >=20 > Can you confirm that this driver will run gru_vtop() in interrupt > context? >=20 > If so, I ll send you another set of patches in which I don't change the > *pte_lookup functions but only change put_page to put_user_page and > remove the ifdef for CONFIG_HUGETLB_PAGE. >=20 > Thank you for your time. >=20 > Thank you > Bharath >=20 > On Sat, Aug 10, 2019 at 01:08:17AM +0530, Bharath Vedartham wrote: > > For pages that were retained via get_user_pages*(), release those pag= es > > via the new put_user_page*() routines, instead of via put_page() or > > release_pages(). > >=20 > > This is part a tree-wide conversion, as described in commit fc1d8e7cc= a2d > > ("mm: introduce put_user_page*(), placeholder versions"). > >=20 > > As part of this conversion, the *pte_lookup functions can be removed = and > > be easily replaced with get_user_pages_fast() functions. In the case = of > > atomic lookup, __get_user_pages_fast() is used, because it does not f= all > > back to the slow path: get_user_pages(). get_user_pages_fast(), on th= e other > > hand, first calls __get_user_pages_fast(), but then falls back to the > > slow path if __get_user_pages_fast() fails. > >=20 > > Also: remove unnecessary CONFIG_HUGETLB ifdefs. > >=20 > > Cc: Ira Weiny > > Cc: John Hubbard > > Cc: J=E9r=F4me Glisse > > Cc: Greg Kroah-Hartman > > Cc: Dimitri Sivanich > > Cc: Arnd Bergmann > > Cc: William Kucharski > > Cc: Christoph Hellwig > > Cc: linux-kernel@vger.kernel.org > > Cc: linux-mm@kvack.org > > Cc: linux-kernel-mentees@lists.linuxfoundation.org > > Reviewed-by: Ira Weiny > > Reviewed-by: John Hubbard > > Reviewed-by: William Kucharski > > Signed-off-by: Bharath Vedartham > > --- > > This is a fold of the 3 patches in the v2 patch series. > > The review tags were given to the individual patches. > >=20 > > Changes since v3 > > - Used gup flags in get_user_pages_fast rather than > > boolean flags. > > Changes since v4 > > - Updated changelog according to John Hubbard. > > --- > > drivers/misc/sgi-gru/grufault.c | 112 +++++++++---------------------= ---------- > > 1 file changed, 24 insertions(+), 88 deletions(-) > >=20 > > diff --git a/drivers/misc/sgi-gru/grufault.c b/drivers/misc/sgi-gru/g= rufault.c > > index 4b713a8..304e9c5 100644 > > --- a/drivers/misc/sgi-gru/grufault.c > > +++ b/drivers/misc/sgi-gru/grufault.c > > @@ -166,96 +166,20 @@ static void get_clear_fault_map(struct gru_stat= e *gru, > > } > > =20 > > /* > > - * Atomic (interrupt context) & non-atomic (user context) functions = to > > - * convert a vaddr into a physical address. The size of the page > > - * is returned in pageshift. > > - * returns: > > - * 0 - successful > > - * < 0 - error code > > - * 1 - (atomic only) try again in non-atomic context > > - */ > > -static int non_atomic_pte_lookup(struct vm_area_struct *vma, > > - unsigned long vaddr, int write, > > - unsigned long *paddr, int *pageshift) > > -{ > > - struct page *page; > > - > > -#ifdef CONFIG_HUGETLB_PAGE > > - *pageshift =3D is_vm_hugetlb_page(vma) ? HPAGE_SHIFT : PAGE_SHIFT; > > -#else > > - *pageshift =3D PAGE_SHIFT; > > -#endif > > - if (get_user_pages(vaddr, 1, write ? FOLL_WRITE : 0, &page, NULL) <= =3D 0) > > - return -EFAULT; > > - *paddr =3D page_to_phys(page); > > - put_page(page); > > - return 0; > > -} > > - > > -/* > > - * atomic_pte_lookup > > + * mmap_sem is already helod on entry to this function. This guarant= ees > > + * existence of the page tables. > > * > > - * Convert a user virtual address to a physical address > > * Only supports Intel large pages (2MB only) on x86_64. > > - * ZZZ - hugepage support is incomplete > > - * > > - * NOTE: mmap_sem is already held on entry to this function. This > > - * guarantees existence of the page tables. > > + * ZZZ - hugepage support is incomplete. > > */ > > -static int atomic_pte_lookup(struct vm_area_struct *vma, unsigned lo= ng vaddr, > > - int write, unsigned long *paddr, int *pageshift) > > -{ > > - pgd_t *pgdp; > > - p4d_t *p4dp; > > - pud_t *pudp; > > - pmd_t *pmdp; > > - pte_t pte; > > - > > - pgdp =3D pgd_offset(vma->vm_mm, vaddr); > > - if (unlikely(pgd_none(*pgdp))) > > - goto err; > > - > > - p4dp =3D p4d_offset(pgdp, vaddr); > > - if (unlikely(p4d_none(*p4dp))) > > - goto err; > > - > > - pudp =3D pud_offset(p4dp, vaddr); > > - if (unlikely(pud_none(*pudp))) > > - goto err; > > - > > - pmdp =3D pmd_offset(pudp, vaddr); > > - if (unlikely(pmd_none(*pmdp))) > > - goto err; > > -#ifdef CONFIG_X86_64 > > - if (unlikely(pmd_large(*pmdp))) > > - pte =3D *(pte_t *) pmdp; > > - else > > -#endif > > - pte =3D *pte_offset_kernel(pmdp, vaddr); > > - > > - if (unlikely(!pte_present(pte) || > > - (write && (!pte_write(pte) || !pte_dirty(pte))))) > > - return 1; > > - > > - *paddr =3D pte_pfn(pte) << PAGE_SHIFT; > > -#ifdef CONFIG_HUGETLB_PAGE > > - *pageshift =3D is_vm_hugetlb_page(vma) ? HPAGE_SHIFT : PAGE_SHIFT; > > -#else > > - *pageshift =3D PAGE_SHIFT; > > -#endif > > - return 0; > > - > > -err: > > - return 1; > > -} > > - > > static int gru_vtop(struct gru_thread_state *gts, unsigned long vadd= r, > > int write, int atomic, unsigned long *gpa, int *pageshift) > > { > > struct mm_struct *mm =3D gts->ts_mm; > > struct vm_area_struct *vma; > > unsigned long paddr; > > - int ret, ps; > > + int ret; > > + struct page *page; > > =20 > > vma =3D find_vma(mm, vaddr); > > if (!vma) > > @@ -263,21 +187,33 @@ static int gru_vtop(struct gru_thread_state *gt= s, unsigned long vaddr, > > =20 > > /* > > * Atomic lookup is faster & usually works even if called in non-at= omic > > - * context. > > + * context. get_user_pages_fast does atomic lookup before falling b= ack to > > + * slow gup. > > */ > > rmb(); /* Must/check ms_range_active before loading PTEs */ > > - ret =3D atomic_pte_lookup(vma, vaddr, write, &paddr, &ps); > > - if (ret) { > > - if (atomic) > > + if (atomic) { > > + ret =3D __get_user_pages_fast(vaddr, 1, write, &page); > > + if (!ret) > > goto upm; > > - if (non_atomic_pte_lookup(vma, vaddr, write, &paddr, &ps)) > > + } else { > > + ret =3D get_user_pages_fast(vaddr, 1, write ? FOLL_WRITE : 0, &pag= e); > > + if (!ret) > > goto inval; > > } > > + > > + paddr =3D page_to_phys(page); > > + put_user_page(page); > > + > > + if (unlikely(is_vm_hugetlb_page(vma))) > > + *pageshift =3D HPAGE_SHIFT; > > + else > > + *pageshift =3D PAGE_SHIFT; > > + > > if (is_gru_paddr(paddr)) > > goto inval; > > - paddr =3D paddr & ~((1UL << ps) - 1); > > + paddr =3D paddr & ~((1UL << *pageshift) - 1); > > *gpa =3D uv_soc_phys_ram_to_gpa(paddr); > > - *pageshift =3D ps; > > + > > return VTOP_SUCCESS; > > =20 > > inval: > > --=20 > > 2.7.4 > >=20