Date: Tue, 7 Dec 2010 11:33:21 -0800 From: mdf@FreeBSD.org To: Marius Strobl <marius@alchemy.franken.de> Cc: src-committers@freebsd.org, Alan Cox <alc@rice.edu>, alc@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org, Max Khon <fjoe@samodelkin.net> Subject: Re: svn commit: r216016 - head/sys/sparc64/include Message-ID: <AANLkTi=q8uVwCtj7H8YYgswx0uPkUXdhsmGHkC8_akO0@mail.gmail.com> In-Reply-To: <20101207134109.GI38282@alchemy.franken.de> References: <201011281926.oASJQKiE040689@svn.freebsd.org> <20101128194542.GF9966@alchemy.franken.de> <AANLkTinwkVO%2BRkr7coYGhuMdZ_UQQa3_18c3D6fBLucA@mail.gmail.com> <20101129192308.GX80343@alchemy.franken.de> <20101129192417.GA18893@alchemy.franken.de> <4CF691A5.8070608@rice.edu> <20101202164727.GB38282@alchemy.franken.de> <4CF7D711.9040505@rice.edu> <20101206220733.GG38282@alchemy.franken.de> <AANLkTinhyfHmdP4K5QVC5tv%2BGN%2BfzNpvU%2BV4JKF_cMHv@mail.gmail.com> <20101207134109.GI38282@alchemy.franken.de>
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On Tue, Dec 7, 2010 at 5:41 AM, Marius Strobl <marius@alchemy.franken.de> w= rote: > On Mon, Dec 06, 2010 at 02:30:01PM -0800, mdf@FreeBSD.org wrote: >> On Mon, Dec 6, 2010 at 2:07 PM, Marius Strobl <marius@alchemy.franken.de= > wrote: >> [lots of snip] >> >> > With that one the kernel now survies memguard_init() but then panics >> > right afterwards when kmeminit() calls kmem_suballoc(): >> > KDB: debugger backends: ddb >> > KDB: current backend: ddb >> > Copyright (c) 1992-2010 The FreeBSD Project. >> > Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 19= 94 >> > ? ? ? ?The Regents of the University of California. All rights reserve= d. >> > FreeBSD is a registered trademark of The FreeBSD Foundation. >> > FreeBSD 9.0-CURRENT #18 r215249:216120M: Mon Dec ?6 13:27:57 CET 2010 >> > ? ?marius@v20z.zeist.de:/home/marius/co/build/head2/sparc64.sparc64/us= r/home/m4 >> > WARNING: WITNESS option enabled, expect reduced performance. >> > panic: kmem_suballoc: bad status return of 3 >> >> [more snip] >> >> Shooting in the dark a little... >> >> The bad status of 3 is presumably KERN_NO_SPACE because we attempted >> to allocate too much space from the kernel_map. =A0What are the actual >> values of vm_kmem_size, kernel_map->min_offset, kernel_map->max_offset >> at panic time? > > vm_kmem_size=3D5610405888 min_offset=3D3221225472 max_offset=3D1395864371= 2 > This is on a US3i machine with 16GB RAM. So kernel_map is from 0xC000_0000 to 0x3_4000_0000, or 0x2_8000_0000 bytes large. Double the vm_kmem_size is 0x2_9CD0_0000, which is why this is failing. This to me says that, for the moment, you need the VM_MAX_KERNEL_ADDRESS define so that memguard does not take up too much virtual space; at the moment this hardware is somewhat constrained on virtual space. Thanks, matthew > >> =A0How much virtual space does sparc64 support (since >> earlier it was reported it's computed based on hardware capability, >> for this specific machine?) >> > > Currently, the limiting factor is that the kernel TSB is addressed > virtually, which means that the TTEs for kernel TSB itself have to be > put into locked dTLB slots taking up 1 4MB dTLB slot per 1GB. US3 > family CPUs have 16 lockable 4MB dTLB and iTLB slots, which need to > be shared between the TSB and the kernel itself though, i.e. a 9MB > kernel also takes up 3 slots (US1/2 machines have 64 dTLB and iTLB > slots but there these are also used for unlocked TTEs so we don't use > more than 32 for kernel plus TSB on these). VM_MAX_KERNEL_ADDRESS is > limited according to how many slots are available for the TSB, that's > what I was referring to previously. > Actually, US3 and later as well as SPARC64 V and later CPUs have > a feature allowing the TSB to be addressed physically, circumventing > the need to lock the TSB into the TLB, thus allowing the full 64-bit > virtual address space to be used. Implementing that is on my TODO > list but unfortunately that's not exactly straight forward and also > requires some instructions to be patched at runtime so the kernel > still works on US1/2 machines. > > Marius > >
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