Messages in this thread | | | Date | Thu, 17 Nov 2011 12:48:52 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH 1/4] x86, amd: Avoid cache aliasing penalties on AMD family 15h |
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Ok, let's ping them directly.
x86 guys, do you have an issue with me backporting the aliasing fix to 3.x stable?
I know it doesn't adhere completely to -stable rules for it not being a regression. Well, think of it as a hardware regression and me trying to cover all bases :-).
Thanks.
On Wed, Nov 16, 2011 at 03:21:36PM -0800, Greg KH wrote: > On Fri, Nov 04, 2011 at 08:25:32AM -0700, Greg KH wrote: > > On Fri, Nov 04, 2011 at 12:26:32PM +0100, Borislav Petkov wrote: > > > From: Borislav Petkov <borislav.petkov@amd.com> > > > > > > Upstream commit: dfb09f9b7ab03fd367740e541a5caf830ed56726 > > > > > > This patch provides performance tuning for the "Bulldozer" CPU. With its > > > shared instruction cache there is a chance of generating an excessive > > > number of cache cross-invalidates when running specific workloads on the > > > cores of a compute module. > > > > > > This excessive amount of cross-invalidations can be observed if cache > > > lines backed by shared physical memory alias in bits [14:12] of their > > > virtual addresses, as those bits are used for the index generation. > > > > > > This patch addresses the issue by clearing all the bits in the [14:12] > > > slice of the file mapping's virtual address at generation time, thus > > > forcing those bits the same for all mappings of a single shared library > > > across processes and, in doing so, avoids instruction cache aliases. > > > > > > It also adds the command line option "align_va_addr=(32|64|on|off)" with > > > which virtual address alignment can be enabled for 32-bit or 64-bit x86 > > > individually, or both, or be completely disabled. > > > > > > This change leaves virtual region address allocation on other families > > > and/or vendors unaffected. > > > > > > Signed-off-by: Borislav Petkov <borislav.petkov@amd.com> > > > Link: http://lkml.kernel.org/r/1312550110-24160-2-git-send-email-bp@amd64.org > > > Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> > > > --- > > > Documentation/kernel-parameters.txt | 13 ++++++ > > > arch/x86/include/asm/elf.h | 31 +++++++++++++ > > > arch/x86/kernel/cpu/amd.c | 13 ++++++ > > > arch/x86/kernel/sys_x86_64.c | 81 +++++++++++++++++++++++++++++++++- > > > arch/x86/mm/mmap.c | 15 ------ > > > arch/x86/vdso/vma.c | 9 ++++ > > > 6 files changed, 144 insertions(+), 18 deletions(-) > > > > I really feel nervous adding this patch to the -stable tree(s). It's > > bigger than "just a bugfix" and it adds new functionality. > > > > I'm aware that it is needed for your new hardware, which is great, but > > it doesn't really follow the Documentation/stable_kernel_rules.txt > > requirements, does it? > > > > I need an ACK from the x86 maintainers before I'm going to be > > comfortable adding this, and then the other, patches in this series. > > > > Peter, Ingo, Thomas, your opinions? > > Ping? > > anyone? > > greg k-h >
-- Regards/Gruss, Boris.
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