Messages in this thread Patch in this message | | | From | Paul Jackson <> | Date | Fri, 03 Feb 2006 23:19:21 -0800 | Subject | [PATCH 3/5] cpuset memory spread slab cache implementation |
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From: Paul Jackson <pj@sgi.com>
Provide the slab cache infrastructure to support cpuset memory spreading.
See the previous patches, cpuset_mem_spread, for an explanation of cpuset memory spreading.
This patch provides a slab cache SLAB_MEM_SPREAD flag. If set in the kmem_cache_create() call defining a slab cache, then any task marked with the process state flag PF_MEMSPREAD will spread memory page allocations for that cache over all the allowed nodes, instead of preferring the local (faulting) node.
On systems not configured with CONFIG_NUMA, this results in no change to the page allocation code path for slab caches.
On systems with cpusets configured in the kernel, but the "memory_spread" cpuset option not enabled for the current tasks cpuset, this adds one failed bit test of the processor state flag PF_MEM_SPREAD on each page allocation for slab caches.
For tasks so marked, a second inline test is done for the slab cache flag SLAB_MEM_SPREAD, and if that is set and if the allocation is not in_interrupt(), this adds a call to to a cpuset routine that computes which of the tasks mems_allowed nodes should be preferred for this allocation.
==> This patch adds another hook into the performance critical code path to allocating objects from the slab cache, in the ____cache_alloc() chunk, below. The next patch optimizes this hook, reducing the impact of the combined mempolicy plus memory spreading hooks on this critical code path to a single check against the tasks task_struct flags word.
This patch provides the generic slab flags and logic needed to apply memory spreading to a particular slab.
A subsequent patch will mark a few specific slab caches for this placement policy.
Signed-off-by: Paul Jackson
---
include/linux/slab.h | 1 + mm/slab.c | 13 +++++++++++-- 2 files changed, 12 insertions(+), 2 deletions(-)
--- 2.6.16-rc1-mm5.orig/include/linux/slab.h 2006-02-03 22:17:31.772404695 -0800 +++ 2.6.16-rc1-mm5/include/linux/slab.h 2006-02-03 22:17:33.545862215 -0800 @@ -47,6 +47,7 @@ typedef struct kmem_cache kmem_cache_t; what is reclaimable later*/ #define SLAB_PANIC 0x00040000UL /* panic if kmem_cache_create() fails */ #define SLAB_DESTROY_BY_RCU 0x00080000UL /* defer freeing pages to RCU */ +#define SLAB_MEM_SPREAD 0x00100000UL /* Spread some memory over cpuset */ /* flags passed to a constructor func */ #define SLAB_CTOR_CONSTRUCTOR 0x001UL /* if not set, then deconstructor */ --- 2.6.16-rc1-mm5.orig/mm/slab.c 2006-02-03 22:17:31.772404695 -0800 +++ 2.6.16-rc1-mm5/mm/slab.c 2006-02-03 22:17:33.549768509 -0800 @@ -94,6 +94,7 @@ #include <linux/interrupt.h> #include <linux/init.h> #include <linux/compiler.h> +#include <linux/cpuset.h> #include <linux/seq_file.h> #include <linux/notifier.h> #include <linux/kallsyms.h> @@ -173,12 +174,12 @@ SLAB_NO_REAP | SLAB_CACHE_DMA | \ SLAB_MUST_HWCACHE_ALIGN | SLAB_STORE_USER | \ SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \ - SLAB_DESTROY_BY_RCU) + SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD) #else # define CREATE_MASK (SLAB_HWCACHE_ALIGN | SLAB_NO_REAP | \ SLAB_CACHE_DMA | SLAB_MUST_HWCACHE_ALIGN | \ SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \ - SLAB_DESTROY_BY_RCU) + SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD) #endif /* @@ -2708,6 +2709,14 @@ static inline void *____cache_alloc(stru if (nid != numa_node_id()) return __cache_alloc_node(cachep, flags, nid); } + if (unlikely(cpuset_mem_spread_check() && + (cachep->flags & SLAB_MEM_SPREAD) && + !in_interrupt())) { + int nid = cpuset_mem_spread_node(); + + if (nid != numa_node_id()) + return __cache_alloc_node(cachep, flags, nid); + } #endif check_irq_off(); -- I won't rest till it's the best ... Programmer, Linux Scalability Paul Jackson <pj@sgi.com> 1.650.933.1373 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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