From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) (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 1D334820DF for ; Tue, 21 Feb 2017 14:35:14 -0800 (PST) Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 21 Feb 2017 14:35:13 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.35,191,1484035200"; d="scan'208";a="67473664" Received: from ahirst-mobl.amr.corp.intel.com (HELO localhost) ([10.252.140.121]) by orsmga005.jf.intel.com with ESMTP; 21 Feb 2017 14:35:12 -0800 MIME-Version: 1.0 To: Laszlo Ersek , edk2-devel-01 Message-ID: <148771651265.11536.450192884498549891@jljusten-ivb> From: Jordan Justen In-Reply-To: Cc: "Ni, Ruiyu" , Andrew Fish , Ard Biesheuvel References: User-Agent: alot/0.5.1 Date: Tue, 21 Feb 2017 14:35:12 -0800 Subject: Re: 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 22:35:14 -0000 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable On 2017-02-21 07:24:11, Laszlo Ersek wrote: > 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? I think grep for EFI_MEMORY_TYPE_INFORMATION_VARIABLE_NAME. -Jordan > - 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 en= tries > > in the UEFI memory map, as dumped by the UEFI shell's MEMMAP comman= d, 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 res= erved > > memory usage. The new preallocation, expressed in kilobytes, is > > trunc(180224 * 1.15 / 1024) =3D 202. This preallocation is approx. = 12.62 > > times the previous preallocation (which was 4 pages, ie. 16384 byte= s). > > > > 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/Platf= orm.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[] =3D { > > - { 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 > = > _______________________________________________ > edk2-devel mailing list > edk2-devel@lists.01.org > https://lists.01.org/mailman/listinfo/edk2-devel