From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966613AbeE2UAP (ORCPT ); Tue, 29 May 2018 16:00:15 -0400 Received: from aserp2120.oracle.com ([141.146.126.78]:53402 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966179AbeE2UAN (ORCPT ); Tue, 29 May 2018 16:00:13 -0400 Subject: Re: [PATCH 2/8] xen/balloon: Move common memory reservation routines to a module To: Oleksandr Andrushchenko , xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org, jgross@suse.com, konrad.wilk@oracle.com Cc: daniel.vetter@intel.com, dongwon.kim@intel.com, matthew.d.roper@intel.com, Oleksandr Andrushchenko References: <20180525153331.31188-1-andr2000@gmail.com> <20180525153331.31188-3-andr2000@gmail.com> <59ab73b0-967b-a82f-3b0d-95f1b0dc40a5@oracle.com> <89de7bdb-8759-419f-63bf-8ed0d57650f0@gmail.com> From: Boris Ostrovsky Openpgp: preference=signencrypt Autocrypt: addr=boris.ostrovsky@oracle.com; prefer-encrypt=mutual; keydata= xsFNBFH8CgsBEAC0KiOi9siOvlXatK2xX99e/J3OvApoYWjieVQ9232Eb7GzCWrItCzP8FUV PQg8rMsSd0OzIvvjbEAvaWLlbs8wa3MtVLysHY/DfqRK9Zvr/RgrsYC6ukOB7igy2PGqZd+M MDnSmVzik0sPvB6xPV7QyFsykEgpnHbvdZAUy/vyys8xgT0PVYR5hyvhyf6VIfGuvqIsvJw5 C8+P71CHI+U/IhsKrLrsiYHpAhQkw+Zvyeml6XSi5w4LXDbF+3oholKYCkPwxmGdK8MUIdkM d7iYdKqiP4W6FKQou/lC3jvOceGupEoDV9botSWEIIlKdtm6C4GfL45RD8V4B9iy24JHPlom woVWc0xBZboQguhauQqrBFooHO3roEeM1pxXjLUbDtH4t3SAI3gt4dpSyT3EvzhyNQVVIxj2 FXnIChrYxR6S0ijSqUKO0cAduenhBrpYbz9qFcB/GyxD+ZWY7OgQKHUZMWapx5bHGQ8bUZz2 SfjZwK+GETGhfkvNMf6zXbZkDq4kKB/ywaKvVPodS1Poa44+B9sxbUp1jMfFtlOJ3AYB0WDS Op3d7F2ry20CIf1Ifh0nIxkQPkTX7aX5rI92oZeu5u038dHUu/dO2EcuCjl1eDMGm5PLHDSP 0QUw5xzk1Y8MG1JQ56PtqReO33inBXG63yTIikJmUXFTw6lLJwARAQABzTNCb3JpcyBPc3Ry b3Zza3kgKFdvcmspIDxib3Jpcy5vc3Ryb3Zza3lAb3JhY2xlLmNvbT7CwXgEEwECACIFAlH8 CgsCGwMGCwkIBwMCBhUIAgkKCwQWAgMBAh4BAheAAAoJEIredpCGysGyasEP/j5xApopUf4g 9Fl3UxZuBx+oduuw3JHqgbGZ2siA3EA4bKwtKq8eT7ekpApn4c0HA8TWTDtgZtLSV5IdH+9z JimBDrhLkDI3Zsx2CafL4pMJvpUavhc5mEU8myp4dWCuIylHiWG65agvUeFZYK4P33fGqoaS VGx3tsQIAr7MsQxilMfRiTEoYH0WWthhE0YVQzV6kx4wj4yLGYPPBtFqnrapKKC8yFTpgjaK jImqWhU9CSUAXdNEs/oKVR1XlkDpMCFDl88vKAuJwugnixjbPFTVPyoC7+4Bm/FnL3iwlJVE qIGQRspt09r+datFzPqSbp5Fo/9m4JSvgtPp2X2+gIGgLPWp2ft1NXHHVWP19sPgEsEJXSr9 tskM8ScxEkqAUuDs6+x/ISX8wa5Pvmo65drN+JWA8EqKOHQG6LUsUdJolFM2i4Z0k40BnFU/ kjTARjrXW94LwokVy4x+ZYgImrnKWeKac6fMfMwH2aKpCQLlVxdO4qvJkv92SzZz4538az1T m+3ekJAimou89cXwXHCFb5WqJcyjDfdQF857vTn1z4qu7udYCuuV/4xDEhslUq1+GcNDjAhB nNYPzD+SvhWEsrjuXv+fDONdJtmLUpKs4Jtak3smGGhZsqpcNv8nQzUGDQZjuCSmDqW8vn2o hWwveNeRTkxh+2x1Qb3GT46uzsFNBFH8CgsBEADGC/yx5ctcLQlB9hbq7KNqCDyZNoYu1HAB Hal3MuxPfoGKObEktawQPQaSTB5vNlDxKihezLnlT/PKjcXC2R1OjSDinlu5XNGc6mnky03q yymUPyiMtWhBBftezTRxWRslPaFWlg/h/Y1iDuOcklhpr7K1h1jRPCrf1yIoxbIpDbffnuyz kuto4AahRvBU4Js4sU7f/btU+h+e0AcLVzIhTVPIz7PM+Gk2LNzZ3/on4dnEc/qd+ZZFlOQ4 KDN/hPqlwA/YJsKzAPX51L6Vv344pqTm6Z0f9M7YALB/11FO2nBB7zw7HAUYqJeHutCwxm7i BDNt0g9fhviNcJzagqJ1R7aPjtjBoYvKkbwNu5sWDpQ4idnsnck4YT6ctzN4I+6lfkU8zMzC gM2R4qqUXmxFIS4Bee+gnJi0Pc3KcBYBZsDK44FtM//5Cp9DrxRQOh19kNHBlxkmEb8kL/pw XIDcEq8MXzPBbxwHKJ3QRWRe5jPNpf8HCjnZz0XyJV0/4M1JvOua7IZftOttQ6KnM4m6WNIZ 2ydg7dBhDa6iv1oKdL7wdp/rCulVWn8R7+3cRK95SnWiJ0qKDlMbIN8oGMhHdin8cSRYdmHK kTnvSGJNlkis5a+048o0C6jI3LozQYD/W9wq7MvgChgVQw1iEOB4u/3FXDEGulRVko6xCBU4 SQARAQABwsFfBBgBAgAJBQJR/AoLAhsMAAoJEIredpCGysGyfvMQAIywR6jTqix6/fL0Ip8G jpt3uk//QNxGJE3ZkUNLX6N786vnEJvc1beCu6EwqD1ezG9fJKMl7F3SEgpYaiKEcHfoKGdh 30B3Hsq44vOoxR6zxw2B/giADjhmWTP5tWQ9548N4VhIZMYQMQCkdqaueSL+8asp8tBNP+TJ PAIIANYvJaD8xA7sYUXGTzOXDh2THWSvmEWWmzok8er/u6ZKdS1YmZkUy8cfzrll/9hiGCTj u3qcaOM6i/m4hqtvsI1cOORMVwjJF4+IkC5ZBoeRs/xW5zIBdSUoC8L+OCyj5JETWTt40+lu qoqAF/AEGsNZTrwHJYu9rbHH260C0KYCNqmxDdcROUqIzJdzDKOrDmebkEVnxVeLJBIhYZUd t3Iq9hdjpU50TA6sQ3mZxzBdfRgg+vaj2DsJqI5Xla9QGKD+xNT6v14cZuIMZzO7w0DoojM4 ByrabFsOQxGvE0w9Dch2BDSI2Xyk1zjPKxG1VNBQVx3flH37QDWpL2zlJikW29Ws86PHdthh Fm5PY8YtX576DchSP6qJC57/eAAe/9ztZdVAdesQwGb9hZHJc75B+VNm4xrh/PJO6c1THqdQ 19WVJ+7rDx3PhVncGlbAOiiiE3NOFPJ1OQYxPKtpBUukAlOTnkKE6QcA4zckFepUkfmBV1wM Jg6OxFYd01z+a+oL Message-ID: Date: Tue, 29 May 2018 16:03:09 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <89de7bdb-8759-419f-63bf-8ed0d57650f0@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Content-Language: en-US X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=8908 signatures=668702 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1805220000 definitions=main-1805290211 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/29/2018 02:22 PM, Oleksandr Andrushchenko wrote: > On 05/29/2018 09:04 PM, Boris Ostrovsky wrote: >> On 05/25/2018 11:33 AM, Oleksandr Andrushchenko wrote: >> @@ -463,11 +457,6 @@ static enum bp_state >> increase_reservation(unsigned long nr_pages) >>       int rc; >>       unsigned long i; >>       struct page   *page; >> -    struct xen_memory_reservation reservation = { >> -        .address_bits = 0, >> -        .extent_order = EXTENT_ORDER, >> -        .domid        = DOMID_SELF >> -    }; >>         if (nr_pages > ARRAY_SIZE(frame_list)) >>           nr_pages = ARRAY_SIZE(frame_list); >> @@ -486,9 +475,7 @@ static enum bp_state >> increase_reservation(unsigned long nr_pages) >>           page = balloon_next_page(page); >>       } >>   -    set_xen_guest_handle(reservation.extent_start, frame_list); >> -    reservation.nr_extents = nr_pages; >> -    rc = HYPERVISOR_memory_op(XENMEM_populate_physmap, &reservation); >> +    rc = xenmem_reservation_increase(nr_pages, frame_list); >>       if (rc <= 0) >>           return BP_EAGAIN; >>   @@ -496,29 +483,7 @@ static enum bp_state >> increase_reservation(unsigned long nr_pages) >>           page = balloon_retrieve(false); >>           BUG_ON(page == NULL); >>   -#ifdef CONFIG_XEN_HAVE_PVMMU >> -        /* >> -         * We don't support PV MMU when Linux and Xen is using >> -         * different page granularity. >> -         */ >> -        BUILD_BUG_ON(XEN_PAGE_SIZE != PAGE_SIZE); >> - >> -        if (!xen_feature(XENFEAT_auto_translated_physmap)) { >> -            unsigned long pfn = page_to_pfn(page); >> - >> -            set_phys_to_machine(pfn, frame_list[i]); >> - >> -            /* Link back into the page tables if not highmem. */ >> -            if (!PageHighMem(page)) { >> -                int ret; >> -                ret = HYPERVISOR_update_va_mapping( >> -                        (unsigned long)__va(pfn << PAGE_SHIFT), >> -                        mfn_pte(frame_list[i], PAGE_KERNEL), >> -                        0); >> -                BUG_ON(ret); >> -            } >> -        } >> -#endif >> +        xenmem_reservation_va_mapping_update(1, &page, &frame_list[i]); >> >> Can you make a single call to xenmem_reservation_va_mapping_update(rc, >> ...)? You need to keep track of pages but presumable they can be put >> into an array (or a list). In fact, perhaps we can have >> balloon_retrieve() return a set of pages. > This is actually how it is used later on for dma-buf, but I just > didn't want > to alter original balloon code too much, but this can be done, in > order of simplicity: > > 1. Similar to frame_list, e.g. static array of struct page* of size > ARRAY_SIZE(frame_list): > more static memory is used, but no allocations > > 2. Allocated at run-time with kcalloc: allocation can fail If this is called in freeing DMA buffer code path or in error path then we shouldn't do it. > > 3. Make balloon_retrieve() return a set of pages: will require > list/array allocation > and handling, allocation may fail, balloon_retrieve prototype change balloon pages are strung on the lru list. Can we keep have balloon_retrieve return a list of pages on that list? -boris > > Could you please tell which of the above will fit better? > >> >>