Date: Thu, 8 Jun 2017 18:10:05 -0500 From: Alan Cox <alc@rice.edu> To: John Baldwin <jhb@freebsd.org> Cc: Bryan Drewery <bdrewery@freebsd.org>, src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r319702 - head/sys/vm Message-ID: <E22C2D48-A27D-4B16-8785-101BEF8BFAD5@rice.edu> In-Reply-To: <1987063.fEClCI1ZXD@ralph.baldwin.cx> References: <201706081618.v58GIfZi066106@repo.freebsd.org> <6910627.IXO0pzjk4q@ralph.baldwin.cx> <207FB492-94EE-47FD-BFB8-18F76C5858A5@rice.edu> <1987063.fEClCI1ZXD@ralph.baldwin.cx>
next in thread | previous in thread | raw e-mail | index | archive | help
> On Jun 8, 2017, at 5:28 PM, John Baldwin <jhb@freebsd.org> wrote: >=20 > On Thursday, June 08, 2017 05:07:40 PM Alan Cox wrote: >>=20 >>> On Jun 8, 2017, at 2:37 PM, John Baldwin <jhb@freebsd.org> wrote: >>>=20 >>> On Thursday, June 08, 2017 12:55:45 PM Bryan Drewery wrote: >>>> On 6/8/17 12:18 PM, John Baldwin wrote: >>>>> Author: jhb >>>>> Date: Thu Jun 8 16:18:41 2017 >>>>> New Revision: 319702 >>>>> URL: https://svnweb.freebsd.org/changeset/base/319702 >>>>>=20 >>>>> Log: >>>>> Fix an off-by-one error in the VM page array on some systems. >>>>>=20 >>>>> r31386 changed how the size of the VM page array was calculated to = be >>>>> less wasteful.=20 >>>>=20 >>>> r313186 >>>=20 >>> Oops. FWIW, this commit fixes a reliable panic booting mips and = mips64 >>> kernels under qemu. Adrian also reported the same panic on real = mips >>> hardware. >>>=20 >>=20 >> Any architecture on which we don=E2=80=99t have superpage = reservations enabled could experience the panic at boot time. Amd64, = arm, arm64, i386, and sparc64 would never panic because of the memory = allocated for the reservation array.=20 >=20 > Even then it seems to not be guaranteed. The original change has > been in CheriBSD for a while, and we have not seen any panics on boot = under > qemu as I saw with plain FreeBSD probably due to slightly different = early > memory allocations. >=20 That makes sense. Only a small subset of all possible memory sizes = would trigger the panic, and that subset amounted to only 2.5% of all = possible memory sizes.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?E22C2D48-A27D-4B16-8785-101BEF8BFAD5>