From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 48CE882218 for ; Tue, 21 Feb 2017 07:24:14 -0800 (PST) Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id BD40D3D944; Tue, 21 Feb 2017 15:24:14 +0000 (UTC) Received: from lacos-laptop-7.usersys.redhat.com (ovpn-116-47.phx2.redhat.com [10.3.116.47]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id v1LFOCp0021557; Tue, 21 Feb 2017 10:24:13 -0500 To: edk2-devel-01 From: Laszlo Ersek Cc: Andrew Fish , "Ni, Ruiyu" , Ard Biesheuvel , "Jordan Justen (Intel address)" Message-ID: Date: Tue, 21 Feb 2017 16:24:11 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.1 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Tue, 21 Feb 2017 15:24:14 +0000 (UTC) Subject: memory type information HOB / UEFI memmap defrag X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 21 Feb 2017 15:24:14 -0000 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Hi, the UEFI memmap under OVMF is getting very fragmented, I'm now counting ~80 entries in it, under various circumstances. I recall that a platform's PlatformPei can "prime" the DXE/UEFI memory allocation system (not the GCD services) for various memory types, by producing a memory type information HOB. My vague understanding is that BDS will in turn check if the actual allocations fit in the allotments from the HOB, and if not, it will try to feed back the increased amount to PEI, for the next boot. As far as I understand, this requires the VariablePei (read only driver) for a platform (so that its PlatformPei can read the info from BDS, and produce the HOB accordingly). Some questions: - how big is VariablePei in binary form? - does it depend on permanent RAM being installed / discovered? - If so, is that dependency implemented with a static DEPEX, or with a callback? Further questions: - what is the variable (GUID and Name) that BDS uses for this information? - What is the format of the variable? - Does the logic depend on particular boot modes? OVMF only supports two boot modes, BOOT_WITH_FULL_CONFIGURATION and BOOT_ON_S3_RESUME. In OVMF we currently use a static array for populating the HOB (see "mDefaultMemoryTypeInformation" in "PlatformPei/Platform.c"). If making it all dynamic is easy, I think I'd like to do it (sometime later). If, however, it would require us to up-end OVMF's PlatformPei, then I think it's not worth it; we can just bump the values in "mDefaultMemoryTypeInformation" suitably. Some examples I consider as up-ending OVMF's PlatformPei: (1) If VariablePei needs permanent RAM with a hard DEPEX. In OVMF, permanent RAM is installed by PlatformPei (thereby potentially unblocking VariablePei's dispatch); however, it is also PlatformPei that would require the r/o variable service to work, because PlatformPei produces the memory type information HOB. So, such a DEPEX in VariablePei would require splitting up PlatformPei, which makes the dynamism totally not worth it. *Maybe* we could add a callback for when the variable service PPI is installed. Dunno. (2) Supporting a third boot mode beyond BOOT_WITH_FULL_CONFIGURATION and BOOT_ON_S3_RESUME. Not even worth the audit of current boot mode checks. Further remarks: - OVMF doesn't care about supporting S4 at the moment, and I personally have no plans to work on that. (I'm saying this because I vaguely recall that the memory type info HOB is related to S4 resume, so an argument could perhaps be made, "this could enable S4 for OVMF". Personally, I'm not interested. Still carrying the scars of S3.) - I actually tried to bump the values in "mDefaultMemoryTypeInformation" quite a few months back, but the benefits I saw were negligible. I was left confused about the memory type info HOB, and that was the reason I didn't ultimately post any patch (and why I stopped pursuing this question). For reference, this was the patch: > commit b357e8d88c0304ea2b31aefafe53d06c9769fb78 > Author: Laszlo Ersek > Date: Thu Sep 17 16:18:46 2015 +0200 > > OvmfPkg: PlatformPei: decrease memmap fragmentation > > Inspired by ArmVirtPkg commit c199315 ("ArmVirtPkg: increase memory > preallocations to reduce region count"), I checked the number of entries > in the UEFI memory map, as dumped by the UEFI shell's MEMMAP command, and > by the Linux kernel. The number of entries is quite high, about 50-55. > > I calculated the new preallocations as follows: > - added 15% to each byte count usage reported by the MEMMAP command, for > some future-proofing, > - expressed the result in kilobytes (both pages and byte counts are hard > to read), > - just for our information, I calculated the ratio between the new > preallocation and the old one. > > For example, the UEFI shell reported 44 pages (180224 bytes) of reserved > memory usage. The new preallocation, expressed in kilobytes, is > trunc(180224 * 1.15 / 1024) = 202. This preallocation is approx. 12.62 > times the previous preallocation (which was 4 pages, ie. 16384 bytes). > > Here's the full table: > > memory type pages from bytes from new KB factor of former > MEMMAP cmd MEMMAP cmd prealloc prealloc > ----------- ---------- ---------- -------- ---------------- > Reserved 44 180224 202 12.62 > LoaderCode 313 1282048 1439 n/a > BS_Code 1300 5324800 5980 3.89 > BS_Data 9053 37081088 41643 2.71 > RT_Code 223 913408 1025 5.33 > RT_Data 789 3231744 3629 25.20 > ACPI_Recl 8 32768 36 1.12 > ACPI_NVS 283 1159168 1301 81.31 > > ... Unfortunately, when the patch is applied, the memory map remains > fragmented; mostly due to small unused Conventional Memory entries between > other types of allocations. The entry count doesn't go below 40. > > Contributed-under: TianoCore Contribution Agreement 1.0 > Signed-off-by: Laszlo Ersek > > diff --git a/OvmfPkg/PlatformPei/Platform.c b/OvmfPkg/PlatformPei/Platform.c > index a6d961673d3a..38abf3811600 100644 > --- a/OvmfPkg/PlatformPei/Platform.c > +++ b/OvmfPkg/PlatformPei/Platform.c > @@ -41,14 +41,15 @@ > #include "Cmos.h" > > EFI_MEMORY_TYPE_INFORMATION mDefaultMemoryTypeInformation[] = { > - { EfiACPIMemoryNVS, 0x004 }, > - { EfiACPIReclaimMemory, 0x008 }, > - { EfiReservedMemoryType, 0x004 }, > - { EfiRuntimeServicesData, 0x024 }, > - { EfiRuntimeServicesCode, 0x030 }, > - { EfiBootServicesCode, 0x180 }, > - { EfiBootServicesData, 0xF00 }, > - { EfiMaxMemoryType, 0x000 } > + { EfiReservedMemoryType, EFI_SIZE_TO_PAGES ((UINTN)SIZE_1KB * 202) }, > + { EfiLoaderCode, EFI_SIZE_TO_PAGES ((UINTN)SIZE_1KB * 1439) }, > + { EfiBootServicesCode, EFI_SIZE_TO_PAGES ((UINTN)SIZE_1KB * 5980) }, > + { EfiBootServicesData, EFI_SIZE_TO_PAGES ((UINTN)SIZE_1KB * 41643) }, > + { EfiRuntimeServicesCode, EFI_SIZE_TO_PAGES ((UINTN)SIZE_1KB * 1025) }, > + { EfiRuntimeServicesData, EFI_SIZE_TO_PAGES ((UINTN)SIZE_1KB * 3629) }, > + { EfiACPIReclaimMemory, EFI_SIZE_TO_PAGES ((UINTN)SIZE_1KB * 36) }, > + { EfiACPIMemoryNVS, EFI_SIZE_TO_PAGES ((UINTN)SIZE_1KB * 1301) }, > + { EfiMaxMemoryType, 0 } > }; > > As you can see in the commit message, at that time the patch only managed to decrease the number of memmap entries from ~55 to ~40, which I found "meh". I figured I'd ask again, because now I'm seeing about 80 entries in the memmap. (I wonder if that is related to OVMF's recently increased ACPI S3 boot script usage!) Thanks, Laszlo