On Thu, 15 Apr 2010 13:29:56 -0400 Lee Schermerhorn <lee.schermerhorn@xxxxxx> wrote: > Against: 2.6.34-rc3-mmotm-100405-1609 > > Rework the generic version of the numa_node_id() function to use the > new generic percpu variable infrastructure. > > Guard the new implementation with a new config option: > > CONFIG_USE_PERCPU_NUMA_NODE_ID. > > Archs which support this new implemention will default this option > to 'y' when NUMA is configured. This config option could be removed > if/when all archs switch over to the generic percpu implementation > of numa_node_id(). Arch support involves: > > 1) converting any existing per cpu variable implementations to use > this implementation. x86_64 is an instance of such an arch. > 2) archs that don't use a per cpu variable for numa_node_id() will > need to initialize the new per cpu variable "numa_node" as cpus > are brought on-line. ia64 is an example. > 3) Defining USE_PERCPU_NUMA_NODE_ID in arch dependent Kconfig--e.g., > when NUMA is configured. This is required because I have > retained the old implementation by default to allow archs to > be modified incrementally, as desired. > > Subsequent patches will convert x86_64 and ia64 to use this > implemenation. > > Signed-off-by: Lee Schermerhorn <lee.schermerhorn@xxxxxx> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> > > --- > > V0: > # From cl@xxxxxxxxxxxxxxxxxxxx Wed Nov 4 10:36:12 2009 > # Date: Wed, 4 Nov 2009 12:35:14 -0500 (EST) > # From: Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx> > # To: Lee Schermerhorn <Lee.Schermerhorn@xxxxxx> > # Subject: Re: [PATCH/RFC] slab: handle memoryless nodes efficiently > # > # I have a very early form of a draft of a patch here that genericizes > # numa_node_id(). Uses the new generic this_cpu_xxx stuff. > # > # Not complete. > > V1: > + split out x86 specific changes to subsequent patch > + split out "numa_mem_id()" and related changes to separate patch > + moved generic definitions of __this_cpu_xxx from linux/percpu.h > to asm-generic/percpu.h where asm/percpu.h and other asm hdrs > can use them. > + export new percpu symbol 'numa_node' in mm/percpu.h > + include <asm/percpu.h> in <linux/topology.h> for use by new > numa_node_id(). > > V2: > + add back the #ifndef/#endif guard around numa_node_id() so that archs > can override generic definition > + add generic stub for set_numa_node() > + use generic percpu numa_node_id() only if enabled by > CONFIG_USE_PERCPU_NUMA_NODE_ID > to allow incremental per arch support. This option could be removed when/if > all archs that support NUMA support this option. > > V3: > + separated the rework of linux/percpu.h into another [preceding] patch. > + moved definition of the numa_node percpu variable from mm/percpu.c to > mm/page-alloc.c > + moved premature definition of cpu_to_mem() to later patch. > > V4: > + topology.h: include <linux/percpu.h> rather than <linux/percpu-defs.h> > Requires Tejun Heo's percpu.h/slab.h cleanup series > > include/linux/topology.h | 33 ++++++++++++++++++++++++++++----- > mm/page_alloc.c | 5 +++++ > 2 files changed, 33 insertions(+), 5 deletions(-) > > Index: linux-2.6.34-rc3-mmotm-100405-1609/mm/page_alloc.c > =================================================================== > --- linux-2.6.34-rc3-mmotm-100405-1609.orig/mm/page_alloc.c 2010-04-07 10:04:04.000000000 -0400 > +++ linux-2.6.34-rc3-mmotm-100405-1609/mm/page_alloc.c 2010-04-07 10:10:23.000000000 -0400 > @@ -56,6 +56,11 @@ > #include <asm/div64.h> > #include "internal.h" > > +#ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID > +DEFINE_PER_CPU(int, numa_node); > +EXPORT_PER_CPU_SYMBOL(numa_node); > +#endif > + > /* > * Array of node states. > */ > Index: linux-2.6.34-rc3-mmotm-100405-1609/include/linux/topology.h > =================================================================== > --- linux-2.6.34-rc3-mmotm-100405-1609.orig/include/linux/topology.h 2010-04-07 09:49:13.000000000 -0400 > +++ linux-2.6.34-rc3-mmotm-100405-1609/include/linux/topology.h 2010-04-07 10:10:23.000000000 -0400 > @@ -31,6 +31,7 @@ > #include <linux/bitops.h> > #include <linux/mmzone.h> > #include <linux/smp.h> > +#include <linux/percpu.h> > #include <asm/topology.h> > > #ifndef node_has_online_mem > @@ -203,8 +204,35 @@ int arch_update_cpu_topology(void); > #ifndef SD_NODE_INIT > #error Please define an appropriate SD_NODE_INIT in include/asm/topology.h!!! > #endif > + > #endif /* CONFIG_NUMA */ > > +#ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID > +DECLARE_PER_CPU(int, numa_node); > + > +#ifndef numa_node_id > +/* Returns the number of the current Node. */ > +#define numa_node_id() __this_cpu_read(numa_node) > +#endif > + > +#ifndef cpu_to_node > +#define cpu_to_node(__cpu) per_cpu(numa_node, (__cpu)) > +#endif > + > +#ifndef set_numa_node > +#define set_numa_node(__node) percpu_write(numa_node, __node) > +#endif > + > +#else /* !CONFIG_USE_PERCPU_NUMA_NODE_ID */ > + > +/* Returns the number of the current Node. */ > +#ifndef numa_node_id > +#define numa_node_id() (cpu_to_node(raw_smp_processor_id())) > + > +#endif > + > +#endif /* [!]CONFIG_USE_PERCPU_NUMA_NODE_ID */ > + > #ifndef topology_physical_package_id > #define topology_physical_package_id(cpu) ((void)(cpu), -1) > #endif > @@ -218,9 +246,4 @@ int arch_update_cpu_topology(void); > #define topology_core_cpumask(cpu) cpumask_of(cpu) > #endif > > -/* Returns the number of the current Node. */ > -#ifndef numa_node_id > -#define numa_node_id() (cpu_to_node(raw_smp_processor_id())) > -#endif > - > #endif /* _LINUX_TOPOLOGY_H */ > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@xxxxxxxxxx For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a> > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . 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