This patch proposes fixes to the reference counting of memory policy in the page allocation paths and in show_numa_map(). Extracted from my "Memory Policy Cleanups and Enhancements" series as stand-alone. Shared policy lookup [shmem] has always added a reference to the policy, but this was never unrefed after page allocation or after formatting the numa map data. Default system policy should not require additional ref counting, nor should the current task's task policy. However, show_numa_map() calls get_vma_policy() to examine what may be [likely is] another task's policy. The latter case needs protection against freeing of the policy. This patch adds a reference count to a mempolicy returned by get_vma_policy() when the policy is a vma policy or another task's mempolicy. Again, shared policy is already reference counted on lookup. A matching "unref" [__mpol_free()] is performed in alloc_page_vma() for shared and vma policies, and in show_numa_map() for shared and another task's mempolicy. We can call __mpol_free() directly, saving an admittedly inexpensive inline NULL test, because we know we have a non-NULL policy. Handling policy ref counts for hugepages is a bit trickier. huge_zonelist() returns a zone list that might come from a shared or vma 'BIND policy. In this case, we should hold the reference until after the huge page allocation in dequeue_hugepage(). The patch modifies huge_zonelist() to return a pointer to the mempolicy if it needs to be unref'd after allocation. Kernel Build [16cpu, 32GB, ia64] - average of 10 runs: w/o patch w/ refcount patch Avg Std Devn Avg Std Devn Real: 100.59 0.38 100.63 0.43 User: 1209.60 0.37 1209.91 0.31 System: 81.52 0.42 81.64 0.34 Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Acked-by: Andi Kleen <ak@suse.de> Cc: Christoph Lameter <clameter@sgi.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The NUMA layer only supports NUMA policies for the highest zone. When ZONE_MOVABLE is configured with kernelcore=, the the highest zone becomes ZONE_MOVABLE. The result is that policies are only applied to allocations like anonymous pages and page cache allocated from ZONE_MOVABLE when the zone is used. This patch applies policies to the two highest zones when the highest zone is ZONE_MOVABLE. As ZONE_MOVABLE consists of pages from the highest "real" zone, it's always functionally equivalent. The patch has been tested on a variety of machines both NUMA and non-NUMA covering x86, x86_64 and ppc64. No abnormal results were seen in kernbench, tbench, dbench or hackbench. It passes regression tests from the numactl package with and without kernelcore= once numactl tests are patched to wait for vmstat counters to update. akpm: this is the nasty hack to fix NUMA mempolicies in the presence of ZONE_MOVABLE and kernelcore= in 2.6.23. Christoph says "For .24 either merge the mobility or get the other solution that Mel is working on. That solution would only use a single zonelist per node and filter on the fly. That may help performance and also help to make memory policies work better." Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Tested-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Acked-by: Christoph Lameter <clameter@sgi.com> Cc: Andi Kleen <ak@suse.de> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Huge pages are not movable so are not allocated from ZONE_MOVABLE. However, as ZONE_MOVABLE will always have pages that can be migrated or reclaimed, it can be used to satisfy hugepage allocations even when the system has been running a long time. This allows an administrator to resize the hugepage pool at runtime depending on the size of ZONE_MOVABLE. This patch adds a new sysctl called hugepages_treat_as_movable. When a non-zero value is written to it, future allocations for the huge page pool will use ZONE_MOVABLE. Despite huge pages being non-movable, we do not introduce additional external fragmentation of note as huge pages are always the largest contiguous block we care about. [akpm@linux-foundation.org: various fixes] Signed-off-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mistyped an ifdef CONFIG_CPUSETS - fixed. I doubt that anyone ever noticed. The impact of this typo was that if someone: 1) was using MPOL_BIND to force off node allocations 2) while using cpusets to constrain memory placement 3) when that cpuset was migrating that jobs memory 4) while the tasks in that job were actively forking then there was a rare chance that future allocations using that MPOL_BIND policy would be node local, not off node. Signed-off-by: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
After we have done this we can now do some typing cleanup. The memory policy layer keeps a policy_zone that specifies the zone that gets memory policies applied. This variable can now be of type enum zone_type. The check_highest_zone function and the build_zonelists funnctionm must then also take a enum zone_type parameter. Plus there are a number of loops over zones that also should use zone_type. We run into some troubles at some points with functions that need a zone_type variable to become -1. Fix that up. [pj@sgi.com: fix set_mempolicy() crash] Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* git://git.infradead.org/hdrcleanup-2.6: (63 commits) [S390] __FD_foo definitions. Switch to __s32 types in joystick.h instead of C99 types for consistency. Add <sys/types.h> to headers included for userspace in <linux/input.h> Move inclusion of <linux/compat.h> out of user scope in asm-x86_64/mtrr.h Remove struct fddi_statistics from user view in <linux/if_fddi.h> Move user-visible parts of drivers/s390/crypto/z90crypt.h to include/asm-s390 Revert include/media changes: Mauro says those ioctls are only used in-kernel(!) Include <linux/types.h> and use __uXX types in <linux/cramfs_fs.h> Use __uXX types in <linux/i2o_dev.h>, include <linux/ioctl.h> too Remove private struct dx_hash_info from public view in <linux/ext3_fs.h> Include <linux/types.h> and use __uXX types in <linux/affs_hardblocks.h> Use __uXX types in <linux/divert.h> for struct divert_blk et al. Use __u32 for elf_addr_t in <asm-powerpc/elf.h>, not u32. It's user-visible. Remove PPP_FCS from user view in <linux/ppp_defs.h>, remove __P mess entirely Use __uXX types in user-visible structures in <linux/nbd.h> Don't use 'u32' in user-visible struct ip_conntrack_old_tuple. Use __uXX types for S390 DASD volume label definitions which are user-visible S390 BIODASDREADCMB ioctl should use __u64 not u64 type. Remove unneeded inclusion of <linux/time.h> from <linux/ufs_fs.h> Fix private integer types used in V4L2 ioctls. ... Manually resolve conflict in include/linux/mtd/physmap.h
From: Ralf Baechle <ralf@linux-mips.org> <linux/mempolicy.h> uses struct mm_struct and relies on a definition or declaration somehow magically being dragged in which may result in a build: [...] CC mm/mempolicy.o In file included from mm/mempolicy.c:69: include/linux/mempolicy.h:150: warning: âstruct mm_structâ declared inside parameter list include/linux/mempolicy.h:150: warning: its scope is only this definition or declaration, which is probably not what you want include/linux/mempolicy.h:175: warning: âstruct mm_structâ declared inside parameter list mm/mempolicy.c:622: error: conflicting types for âdo_migrate_pagesâ include/linux/mempolicy.h:175: error: previous declaration of âdo_migrate_pagesâ was here mm/mempolicy.c:1661: error: conflicting types for âmpol_rebind_mmâ include/linux/mempolicy.h:150: error: previous declaration of âmpol_rebind_mmâ was here make[1]: *** [mm/mempolicy.o] Error 1 make: *** [mm] Error 2 [ralf@denk linux-ip35]$ Including <linux/sched.h> is a step into direction of include hell so fixed by adding a forward declaration of struct mm_struct instead. Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
The hooks in the slab cache allocator code path for support of NUMA mempolicies and cpuset memory spreading are in an important code path. Many systems will use neither feature. This patch optimizes those hooks down to a single check of some bits in the current tasks task_struct flags. For non NUMA systems, this hook and related code is already ifdef'd out. The optimization is done by using another task flag, set if the task is using a non-default NUMA mempolicy. Taking this flag bit along with the PF_SPREAD_PAGE and PF_SPREAD_SLAB flag bits added earlier in this 'cpuset memory spreading' patch set, one can check for the combination of any of these special case memory placement mechanisms with a single test of the current tasks task_struct flags. This patch also tightens up the code, to save a few bytes of kernel text space, and moves some of it out of line. Due to the nested inlines called from multiple places, we were ending up with three copies of this code, which once we get off the main code path (for local node allocation) seems a bit wasteful of instruction memory. Signed-off-by: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch fixes a regression in 2.6.14 against 2.6.13 that causes an imbalance in memory allocation during bootup. The slab allocator in 2.6.13 is not numa aware and simply calls alloc_pages(). This means that memory policies may control the behavior of alloc_pages(). During bootup the memory policy is set to MPOL_INTERLEAVE resulting in the spreading out of allocations during bootup over all available nodes. The slab allocator in 2.6.13 has only a single list of slab pages. As a result the per cpu slab cache and the spinlock controlled page lists may contain slab entries from off node memory. The slab allocator in 2.6.13 makes no effort to discern the locality of an entry on its lists. The NUMA aware slab allocator in 2.6.14 controls locality of the slab pages explicitly by calling alloc_pages_node(). The NUMA slab allocator manages slab entries by having lists of available slab pages for each node. The per cpu slab cache can only contain slab entries associated with the node local to the processor. This guarantees that the default allocation mode of the slab allocator always assigns local memory if available. Setting MPOL_INTERLEAVE as a default policy during bootup has no effect anymore. In 2.6.14 all node unspecific slab allocations are performed on the boot processor. This means that most of key data structures are allocated on one node. Most processors will have to refer to these structures making the boot node a potential bottleneck. This may reduce performance and cause unnecessary memory pressure on the boot node. This patch implements NUMA policies in the slab layer. There is the need of explicit application of NUMA memory policies by the slab allcator itself since the NUMA slab allocator does no longer let the page_allocator control locality. The check for policies is made directly at the beginning of __cache_alloc using current->mempolicy. The memory policy is already frequently checked by the page allocator (alloc_page_vma() and alloc_page_current()). So it is highly likely that the cacheline is present. For MPOL_INTERLEAVE kmalloc() will spread out each request to one node after another so that an equal distribution of allocations can be obtained during bootup. It is not possible to push the policy check to lower layers of the NUMA slab allocator since the per cpu caches are now only containing slab entries from the current node. If the policy says that the local node is not to be preferred or forbidden then there is no point in checking the slab cache or local list of slab pages. The allocation better be directed immediately to the lists containing slab entries for the allowed set of nodes. This way of applying policy also fixes another strange behavior in 2.6.13. alloc_pages() is controlled by the memory allocation policy of the current process. It could therefore be that one process is running with MPOL_INTERLEAVE and would f.e. obtain a new page following that policy since no slab entries are in the lists anymore. A page can typically be used for multiple slab entries but lets say that the current process is only using one. The other entries are then added to the slab lists. These are now non local entries in the slab lists despite of the possible availability of local pages that would provide faster access and increase the performance of the application. Another process without MPOL_INTERLEAVE may now run and expect a local slab entry from kmalloc(). However, there are still these free slab entries from the off node page obtained from the other process via MPOL_INTERLEAVE in the cache. The process will then get an off node slab entry although other slab entries may be available that are local to that process. This means that the policy if one process may contaminate the locality of the slab caches for other processes. This patch in effect insures that a per process policy is followed for the allocation of slab entries and that there cannot be a memory policy influence from one process to another. A process with default policy will always get a local slab entry if one is available. And the process using memory policies will get its memory arranged as requested. Off-node slab allocation will require the use of spinlocks and will make the use of per cpu caches not possible. A process using memory policies to redirect allocations offnode will have to cope with additional lock overhead in addition to the latency added by the need to access a remote slab entry. Changes V1->V2 - Remove #ifdef CONFIG_NUMA by moving forward declaration into prior #ifdef CONFIG_NUMA section. - Give the function determining the node number to use a saner name. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>