From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave.Martin@arm.com (Dave Martin) Date: Thu, 10 Apr 2014 10:56:59 +0100 Subject: [PATCH v2 06/12] ARM: mcpm: change max clusters to 4 In-Reply-To: <1396944052-9887-7-git-send-email-haojian.zhuang@linaro.org> References: <1396944052-9887-1-git-send-email-haojian.zhuang@linaro.org> <1396944052-9887-7-git-send-email-haojian.zhuang@linaro.org> Message-ID: <20140410095650.GA5499@e103592.cambridge.arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Apr 08, 2014 at 04:00:46PM +0800, Haojian Zhuang wrote: > In order to support 4 clusters with 4 Cortex A15 Cores in each cluster, > enlarge maximum clusters from 2 to 4 in MCPM. CC Nico on mcpm patches please. I'm happy to be CC'd as well. > > Signed-off-by: Haojian Zhuang > --- > arch/arm/include/asm/mcpm.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm/include/asm/mcpm.h b/arch/arm/include/asm/mcpm.h > index 608516e..68f82cf 100644 > --- a/arch/arm/include/asm/mcpm.h > +++ b/arch/arm/include/asm/mcpm.h > @@ -20,7 +20,7 @@ > * to consider dynamic allocation. > */ > #define MAX_CPUS_PER_CLUSTER 4 > -#define MAX_NR_CLUSTERS 2 > +#define MAX_NR_CLUSTERS 4 Because of the need for alignment to the biggest cacheline size in the system, the MCPM low-level locking structures consume a non-trivial amount of memory. Therefore, I'm not keen on the idea of simply increasing this #define every time a platform appears with a larger number of clusters. If hip04 is not built into the kernel, this just wastes memory. I'll leave it to Nico to decide whether we can increase the #define to 4 or whether this needs a proper fix now. Ideally, we would have a way of choosing the maximum value required by the set of boards built into the kernel, or switch to dynamic allocation. Cheers ---Dave