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* [PATCH] radix-tree: RCU lockless readsideNick Piggin2006-12-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make radix tree lookups safe to be performed without locks. Readers are protected against nodes being deleted by using RCU based freeing. Readers are protected against new node insertion by using memory barriers to ensure the node itself will be properly written before it is visible in the radix tree. Each radix tree node keeps a record of their height (above leaf nodes). This height does not change after insertion -- when the radix tree is extended, higher nodes are only inserted in the top. So a lookup can take the pointer to what is *now* the root node, and traverse down it even if the tree is concurrently extended and this node becomes a subtree of a new root. "Direct" pointers (tree height of 0, where root->rnode points directly to the data item) are handled by using the low bit of the pointer to signal whether rnode is a direct pointer or a pointer to a radix tree node. When a reader wants to traverse the next branch, they will take a copy of the pointer. This pointer will be either NULL (and the branch is empty) or non-NULL (and will point to a valid node). [akpm@osdl.org: cleanups] [Lee.Schermerhorn@hp.com: bugfixes, comments, simplifications] [clameter@sgi.com: build fix] Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Christoph Lameter <clameter@engr.sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] mm: make compound page destructor handling explicitAndy Whitcroft2006-12-07
| | | | | | | | | | | | | | | Currently we we use the lru head link of the second page of a compound page to hold its destructor. This was ok when it was purely an internal implmentation detail. However, hugetlbfs overrides this destructor violating the layering. Abstract this out as explicit calls, also introduce a type for the callback function allowing them to be type checked. For each callback we pre-declare the function, causing a type error on definition rather than on use elsewhere. [akpm@osdl.org: cleanups] Signed-off-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] slab: better fallback allocation behaviorChristoph Lameter2006-12-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently we simply attempt to allocate from all allowed nodes using GFP_THISNODE. However, GFP_THISNODE does not do reclaim (it wont do any at all if the recent GFP_THISNODE patch is accepted). If we truly run out of memory in the whole system then fallback_alloc may return NULL although memory may still be available if we would perform more thorough reclaim. This patch changes fallback_alloc() so that we first only inspect all the per node queues for available slabs. If we find any then we allocate from those. This avoids slab fragmentation by first getting rid of all partial allocated slabs on every node before allocating new memory. If we cannot satisfy the allocation from any per node queue then we extend a slab. We now call into the page allocator without specifying GFP_THISNODE. The page allocator will then implement its own fallback (in the given cpuset context), perform necessary reclaim (again considering not a single node but the whole set of allowed nodes) and then return pages for a new slab. We identify from which node the pages were allocated and then insert the pages into the corresponding per node structure. In order to do so we need to modify cache_grow() to take a parameter that specifies the new slab. kmem_getpages() can no longer set the GFP_THISNODE flag since we need to be able to use kmem_getpage to allocate from an arbitrary node. GFP_THISNODE needs to be specified when calling cache_grow(). One key advantage is that the decision from which node to allocate new memory is removed from slab fallback processing. The patch allows to go back to use of the page allocators fallback/reclaim logic. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] GFP_THISNODE must not trigger global reclaimChristoph Lameter2006-12-07
| | | | | | | | | | | | | | | | | | | | | | | | | The intent of GFP_THISNODE is to make sure that an allocation occurs on a particular node. If this is not possible then NULL needs to be returned so that the caller can choose what to do next on its own (the slab allocator depends on that). However, GFP_THISNODE currently triggers reclaim before returning a failure (GFP_THISNODE means GFP_NORETRY is set). If we have over allocated a node then we will currently do some reclaim before returning NULL. The caller may want memory from other nodes before reclaim should be triggered. (If the caller wants reclaim then he can directly use __GFP_THISNODE instead). There is no flag to avoid reclaim in the page allocator and adding yet another GFP_xx flag would be difficult given that we are out of available flags. So just compare and see if all bits for GFP_THISNODE (__GFP_THISNODE, __GFP_NORETRY and __GFP_NOWARN) are set. If so then we return NULL before waking up kswapd. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] slab: fix two issues in kmalloc_node / __cache_alloc_nodeChristoph Lameter2006-12-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This addresses two issues: 1. Kmalloc_node() may intermittently return NULL if we are allocating from the current node and are unable to obtain memory for the current node from the page allocator. This is because we call ___cache_alloc() if nodeid == numa_node_id() and ____cache_alloc is not able to fallback to other nodes. This was introduced in the 2.6.19 development cycle. <= 2.6.18 in that case does not do a restricted allocation and blindly trusts the page allocator to have given us memory from the indicated node. It inserts the page regardless of the node it came from into the queues for the current node. 2. If kmalloc_node() is used on a node that has not been bootstrapped yet then we may try to pass an invalid node number to ____cache_alloc_node() triggering a BUG(). Change the function to call fallback_alloc() instead. Only call fallback_alloc() if we are allowed to fallback at all. The need to handle a node not bootstrapped yet also first surfaced in the 2.6.19 cycle. Update the comments since they were still describing the old kmalloc_node from 2.6.12. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] slab: remove SLAB_DMAChristoph Lameter2006-12-07
| | | | | | | | | SLAB_DMA is an alias of GFP_DMA. This is the last one so we remove the leftover comment too. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] slab: remove SLAB_KERNELChristoph Lameter2006-12-07
| | | | | | | | SLAB_KERNEL is an alias of GFP_KERNEL. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] slab: remove SLAB_LEVEL_MASKChristoph Lameter2006-12-07
| | | | | | | | | SLAB_LEVEL_MASK is only used internally to the slab and is and alias of GFP_LEVEL_MASK. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] slab: remove SLAB_NO_GROWChristoph Lameter2006-12-07
| | | | | | | | It is only used internally in the slab. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] kill install_file_pte's pte_valHugh Dickins2006-12-07
| | | | | | | | | | David Binderman and his Intel C compiler rightly observe that install_file_pte no longer has any use for its pte_val. Signed-off-by: Hugh Dickins <hugh@veritas.com> Cc: d binderman <dcb314@hotmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] mm: cleanup indentation on switch for CPU operationsAndy Whitcroft2006-12-07
| | | | | | | | | | | | | | | These patches introduced new switch statements which are indented contrary to the concensus in mm/*.c. Fix them up to match that concensus. [PATCH] node local per-cpu-pages [PATCH] ZVC: Scale thresholds depending on the size of the system commit e7c8d5c9955a4d2e88e36b640563f5d6d5aba48a commit df9ecaba3f152d1ea79f2a5e0b87505e03f47590 Signed-off-by: Andy Whitcroft <apw@shadowen.org> Cc: Christoph Lameter <clameter@engr.sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] reject corrupt swapfiles earlierEric Sandeen2006-12-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The fsfuzzer found this; with a corrupt small swapfile that claims to have many pages: [root]# file swap.741.img swap.741.img: Linux/i386 swap file (new style) 1 (4K pages) size 1040191487 pages [root]# ls -l swap.741.img -rw-r--r-- 1 root root 16777216 Nov 22 05:18 swap.741.img sys_swapon() will try to vmalloc all those pages, and -then- check to see if the file is actually that large: if (!(p->swap_map = vmalloc(maxpages * sizeof(short)))) { <snip> if (swapfilesize && maxpages > swapfilesize) { printk(KERN_WARNING "Swap area shorter than signature indicates\n"); It seems to me that it would make more sense to move this test up before the vmalloc, with the other checks, to avoid the OOM-killer in this situation... Signed-off-by: Eric Sandeen <sandeen@redhat.com> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] numa node ids are int, page_to_nid and zone_to_nid should return intAndy Whitcroft2006-12-07
| | | | | | | | | | | | | | | | | | | | | | | NUMA node ids are passed as either int or unsigned int almost exclusivly page_to_nid and zone_to_nid both return unsigned long. This is a throw back to when page_to_nid was a #define and was thus exposing the real type of the page flags field. In addition to fixing up the definitions of page_to_nid and zone_to_nid I audited the users of these functions identifying the following incorrect uses: 1) mm/page_alloc.c show_node() -- printk dumping the node id, 2) include/asm-ia64/pgalloc.h pgtable_quicklist_free() -- comparison against numa_node_id() which returns an int from cpu_to_node(), and 3) mm/mpolicy.c check_pte_range -- used as an index in node_isset which uses bit_set which in generic code takes an int. Signed-off-by: Andy Whitcroft <apw@shadowen.org> Cc: Christoph Lameter <clameter@engr.sgi.com> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] drain_node_page(): Drain pages in batch unitsChristoph Lameter2006-12-07
| | | | | | | | | | | | | drain_node_pages() currently drains the complete pageset of all pages. If there are a large number of pages in the queues then we may hold off interrupts for too long. Duplicate the method used in free_hot_cold_page. Only drain pcp->batch pages at one time. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] make mm/thrash.c:global_faults staticAdrian Bunk2006-12-07
| | | | | | | | This patch makes the needlessly global "global_faults" static. Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] enable booting a NUMA system where some nodes have no memoryChristian Krafft2006-12-07
| | | | | | | | | | | | | | | When booting a NUMA system with nodes that have no memory (eg by limiting memory), bootmem_alloc_core tried to find pages in an uninitialized bootmem_map. This caused a null pointer access. This fix adds a check, so that NULL is returned. That will enable the caller (bootmem_alloc_nopanic) to alloc memory on other without a panic. Signed-off-by: Christian Krafft <krafft@de.ibm.com> Cc: Christoph Lameter <clameter@engr.sgi.com> Cc: Andy Whitcroft <apw@shadowen.org> Cc: Martin Bligh <mbligh@google.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Allow NULL pointers in percpu_freeAlan Stern2006-12-07
| | | | | | | | | | | | | | The patch (as824b) makes percpu_free() ignore NULL arguments, as one would expect for a deallocation routine. (Note that free_percpu is #defined as percpu_free in include/linux/percpu.h.) A few callers are updated to remove now-unneeded tests for NULL. A few other callers already seem to assume that passing a NULL pointer to percpu_free() is okay! The patch also removes an unnecessary NULL check in percpu_depopulate(). Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] leak tracking for kmalloc_nodeChristoph Hellwig2006-12-07
| | | | | | | | | | | | | | | | We have variants of kmalloc and kmem_cache_alloc that leave leak tracking to the caller. This is used for subsystem-specific allocators like skb_alloc. To make skb_alloc node-aware we need similar routines for the node-aware slab allocator, which this patch adds. Note that the code is rather ugly, but it mirrors the non-node-aware code 1:1: [akpm@osdl.org: add module export] Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Always print out the header line in /proc/swapsSuleiman Souhlal2006-12-07
| | | | | | | | | | | | | | | It would be possible for /proc/swaps to not always print out the header: swapon /dev/hdc2 swapon /dev/hde2 swapoff /dev/hdc2 At this point /proc/swaps would not have a header. Signed-off-by: Suleiman Souhlal <suleiman@google.com> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] OOM can panic due to processes stuck in __alloc_pages()Kirill Korotaev2006-12-07
| | | | | | | | | | | | | | | | | OOM can panic due to the processes stuck in __alloc_pages() doing infinite rebalance loop while no memory can be reclaimed. OOM killer tries to kill some processes, but unfortunetaly, rebalance label was moved by someone below the TIF_MEMDIE check, so buddy allocator doesn't see that process is OOM-killed and it can simply fail the allocation :/ Observed in reality on RHEL4(2.6.9)+OpenVZ kernel when a user doing some memory allocation tricks triggered OOM panic. Signed-off-by: Denis Lunev <den@sw.ru> Signed-off-by: Kirill Korotaev <dev@openvz.org> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] mlock cleanupRik Bobbaers2006-12-07
| | | | | | | | mm is defined as vma->vm_mm, so use that. Acked-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] mm: add noaliencache boot option to disable numa alien cachesPaul Menage2006-12-07
| | | | | | | | | | | | | | | | | When using numa=fake on non-NUMA hardware there is no benefit to having the alien caches, and they consume much memory. Add a kernel boot option to disable them. Christoph sayeth "This is good to have even on large NUMA. The problem is that the alien caches grow by the square of the size of the system in terms of nodes." Cc: Christoph Lameter <clameter@engr.sgi.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] mm: slab: eliminate lock_cpu_hotplug from slabRavikiran G Thirumalai2006-12-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Here's an attempt towards doing away with lock_cpu_hotplug in the slab subsystem. This approach also fixes a bug which shows up when cpus are being offlined/onlined and slab caches are being tuned simultaneously. http://marc.theaimsgroup.com/?l=linux-kernel&m=116098888100481&w=2 The patch has been stress tested overnight on a 2 socket 4 core AMD box with repeated cpu online and offline, while dbench and kernbench process are running, and slab caches being tuned at the same time. There were no lockdep warnings either. (This test on 2,6.18 as 2.6.19-rc crashes at __drain_pages http://marc.theaimsgroup.com/?l=linux-kernel&m=116172164217678&w=2 ) The approach here is to hold cache_chain_mutex from CPU_UP_PREPARE until CPU_ONLINE (similar in approach as worqueue_mutex) . Slab code sensitive to cpu_online_map (kmem_cache_create, kmem_cache_destroy, slabinfo_write, __cache_shrink) is already serialized with cache_chain_mutex. (This patch lengthens cache_chain_mutex hold time at kmem_cache_destroy to cover this). This patch also takes the cache_chain_sem at kmem_cache_shrink to protect sanity of cpu_online_map at __cache_shrink, as viewed by slab. (kmem_cache_shrink->__cache_shrink->drain_cpu_caches). But, really, kmem_cache_shrink is used at just one place in the acpi subsystem! Do we really need to keep kmem_cache_shrink at all? Another note. Looks like a cpu hotplug event can send CPU_UP_CANCELED to a registered subsystem even if the subsystem did not receive CPU_UP_PREPARE. This could be due to a subsystem registered for notification earlier than the current subsystem crapping out with NOTIFY_BAD. Badness can occur with in the CPU_UP_CANCELED code path at slab if this happens (The same would apply for workqueue.c as well). To overcome this, we might have to use either a) a per subsystem flag and avoid handling of CPU_UP_CANCELED, or b) Use a special notifier events like LOCK_ACQUIRE/RELEASE as Gautham was using in his experiments, or c) Do not send CPU_UP_CANCELED to a subsystem which did not receive CPU_UP_PREPARE. I would prefer c). Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org> Signed-off-by: Shai Fultheim <shai@scalex86.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] slab debug and ARCH_SLAB_MINALIGN don't get alongKevin Hilman2006-12-07
| | | | | | | | | | | | | | | | | | When CONFIG_SLAB_DEBUG is used in combination with ARCH_SLAB_MINALIGN, some debug flags should be disabled which depend on BYTES_PER_WORD alignment. The disabling of these debug flags is not properly handled when BYTES_PER_WORD < ARCH_SLAB_MEMALIGN < cache_line_size() This patch fixes that and also adds an alignment check to cache_alloc_debugcheck_after() when ARCH_SLAB_MINALIGN is used. Signed-off-by: Kevin Hilman <khilman@mvista.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Christoph Lameter <clameter@engr.sgi.com> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] htlb forget rss with pt sharingChen, Kenneth W2006-12-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Imprecise RSS accounting is an irritating ill effect with pt sharing. After consulted with several VM experts, I have tried various methods to solve that problem: (1) iterate through all mm_structs that share the PT and increment count; (2) keep RSS count in page table structure and then sum them up at reporting time. None of the above methods yield any satisfactory implementation. Since process RSS accounting is pure information only, I propose we don't count them at all for hugetlb page. rlimit has such field, though there is absolutely no enforcement on limiting that resource. One other method is to account all RSS at hugetlb mmap time regardless they are faulted or not. I opt for the simplicity of no accounting at all. Hugetlb page are special, they are reserved up front in global reservation pool and is not reclaimable. From physical memory resource point of view, it is already consumed regardless whether there are users using them. If the concern is that RSS can be used to control resource allocation, we already can specify hugetlb fs size limit and sysadmin can enforce that at mount time. Combined with the two points mentioned above, I fail to see if there is anything got affected because of this patch. Signed-off-by: Ken Chen <kenneth.w.chen@intel.com> Acked-by: Hugh Dickins <hugh@veritas.com> Cc: Dave McCracken <dmccr@us.ibm.com> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: Adam Litke <agl@us.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] shared page table for hugetlb pageChen, Kenneth W2006-12-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Following up with the work on shared page table done by Dave McCracken. This set of patch target shared page table for hugetlb memory only. The shared page table is particular useful in the situation of large number of independent processes sharing large shared memory segments. In the normal page case, the amount of memory saved from process' page table is quite significant. For hugetlb, the saving on page table memory is not the primary objective (as hugetlb itself already cuts down page table overhead significantly), instead, the purpose of using shared page table on hugetlb is to allow faster TLB refill and smaller cache pollution upon TLB miss. With PT sharing, pte entries are shared among hundreds of processes, the cache consumption used by all the page table is smaller and in return, application gets much higher cache hit ratio. One other effect is that cache hit ratio with hardware page walker hitting on pte in cache will be higher and this helps to reduce tlb miss latency. These two effects contribute to higher application performance. Signed-off-by: Ken Chen <kenneth.w.chen@intel.com> Acked-by: Hugh Dickins <hugh@veritas.com> Cc: Dave McCracken <dmccr@us.ibm.com> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: Adam Litke <agl@us.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] balance_pdgat() cleanupAndrew Morton2006-12-07
| | | | | | | Despaghettify balance_pdgat() a bit. Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] mm: add arch_alloc_pageNick Piggin2006-12-07
| | | | | | | | Add an arch_alloc_page to match arch_free_page. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] new scheme to preempt swap tokenAshwin Chaugule2006-12-07
| | | | | | | | | | | | | | | | | | | | The new swap token patches replace the current token traversal algo. The old algo had a crude timeout parameter that was used to handover the token from one task to another. This algo, transfers the token to the tasks that are in need of the token. The urgency for the token is based on the number of times a task is required to swap-in pages. Accordingly, the priority of a task is incremented if it has been badly affected due to swap-outs. To ensure that the token doesnt bounce around rapidly, the token holders are given a priority boost. The priority of tasks is also decremented, if their rate of swap-in's keeps reducing. This way, the condition to check whether to pre-empt the swap token, is a matter of comparing two task's priority fields. [akpm@osdl.org: cleanups] Signed-off-by: Ashwin Chaugule <ashwin.chaugule@celunite.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] grab swap token reorderedAshwin Chaugule2006-12-07
| | | | | | | | | | | Make sure the contention for the token happens _before_ any read-in and kicks the swap-token algo only when the VM is under pressure. Signed-off-by: Ashwin Chaugule <ashwin.chaugule@celunite.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] oom: less memdieNick Piggin2006-12-07
| | | | | | | | | | | Don't cause all threads in all other thread groups to gain TIF_MEMDIE otherwise we'll get a thundering herd eating our memory reserve. This may not be the optimal scheme, but it fits our policy of allowing just one TIF_MEMDIE in the system at once. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] oom: cleanup messagesNick Piggin2006-12-07
| | | | | | | | Clean up the OOM killer messages to be more consistent. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] oom: don't kill unkillable children or siblingsNick Piggin2006-12-07
| | | | | | | | | | Abort the kill if any of our threads have OOM_DISABLE set. Having this test here also prevents any OOM_DISABLE child of the "selected" process from being killed. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] memory page_alloc zonelist caching speedupPaul Jackson2006-12-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Optimize the critical zonelist scanning for free pages in the kernel memory allocator by caching the zones that were found to be full recently, and skipping them. Remembers the zones in a zonelist that were short of free memory in the last second. And it stashes a zone-to-node table in the zonelist struct, to optimize that conversion (minimize its cache footprint.) Recent changes: This differs in a significant way from a similar patch that I posted a week ago. Now, instead of having a nodemask_t of recently full nodes, I have a bitmask of recently full zones. This solves a problem that last weeks patch had, which on systems with multiple zones per node (such as DMA zone) would take seeing any of these zones full as meaning that all zones on that node were full. Also I changed names - from "zonelist faster" to "zonelist cache", as that seemed to better convey what we're doing here - caching some of the key zonelist state (for faster access.) See below for some performance benchmark results. After all that discussion with David on why I didn't need them, I went and got some ;). I wanted to verify that I had not hurt the normal case of memory allocation noticeably. At least for my one little microbenchmark, I found (1) the normal case wasn't affected, and (2) workloads that forced scanning across multiple nodes for memory improved up to 10% fewer System CPU cycles and lower elapsed clock time ('sys' and 'real'). Good. See details, below. I didn't have the logic in get_page_from_freelist() for various full nodes and zone reclaim failures correct. That should be fixed up now - notice the new goto labels zonelist_scan, this_zone_full, and try_next_zone, in get_page_from_freelist(). There are two reasons I persued this alternative, over some earlier proposals that would have focused on optimizing the fake numa emulation case by caching the last useful zone: 1) Contrary to what I said before, we (SGI, on large ia64 sn2 systems) have seen real customer loads where the cost to scan the zonelist was a problem, due to many nodes being full of memory before we got to a node we could use. Or at least, I think we have. This was related to me by another engineer, based on experiences from some time past. So this is not guaranteed. Most likely, though. The following approach should help such real numa systems just as much as it helps fake numa systems, or any combination thereof. 2) The effort to distinguish fake from real numa, using node_distance, so that we could cache a fake numa node and optimize choosing it over equivalent distance fake nodes, while continuing to properly scan all real nodes in distance order, was going to require a nasty blob of zonelist and node distance munging. The following approach has no new dependency on node distances or zone sorting. See comment in the patch below for a description of what it actually does. Technical details of note (or controversy): - See the use of "zlc_active" and "did_zlc_setup" below, to delay adding any work for this new mechanism until we've looked at the first zone in zonelist. I figured the odds of the first zone having the memory we needed were high enough that we should just look there, first, then get fancy only if we need to keep looking. - Some odd hackery was needed to add items to struct zonelist, while not tripping up the custom zonelists built by the mm/mempolicy.c code for MPOL_BIND. My usual wordy comments below explain this. Search for "MPOL_BIND". - Some per-node data in the struct zonelist is now modified frequently, with no locking. Multiple CPU cores on a node could hit and mangle this data. The theory is that this is just performance hint data, and the memory allocator will work just fine despite any such mangling. The fields at risk are the struct 'zonelist_cache' fields 'fullzones' (a bitmask) and 'last_full_zap' (unsigned long jiffies). It should all be self correcting after at most a one second delay. - This still does a linear scan of the same lengths as before. All I've optimized is making the scan faster, not algorithmically shorter. It is now able to scan a compact array of 'unsigned short' in the case of many full nodes, so one cache line should cover quite a few nodes, rather than each node hitting another one or two new and distinct cache lines. - If both Andi and Nick don't find this too complicated, I will be (pleasantly) flabbergasted. - I removed the comment claiming we only use one cachline's worth of zonelist. We seem, at least in the fake numa case, to have put the lie to that claim. - I pay no attention to the various watermarks and such in this performance hint. A node could be marked full for one watermark, and then skipped over when searching for a page using a different watermark. I think that's actually quite ok, as it will tend to slightly increase the spreading of memory over other nodes, away from a memory stressed node. =============== Performance - some benchmark results and analysis: This benchmark runs a memory hog program that uses multiple threads to touch alot of memory as quickly as it can. Multiple runs were made, touching 12, 38, 64 or 90 GBytes out of the total 96 GBytes on the system, and using 1, 19, 37, or 55 threads (on a 56 CPU system.) System, user and real (elapsed) timings were recorded for each run, shown in units of seconds, in the table below. Two kernels were tested - 2.6.18-mm3 and the same kernel with this zonelist caching patch added. The table also shows the percentage improvement the zonelist caching sys time is over (lower than) the stock *-mm kernel. number 2.6.18-mm3 zonelist-cache delta (< 0 good) percent GBs N ------------ -------------- ---------------- systime mem threads sys user real sys user real sys user real better 12 1 153 24 177 151 24 176 -2 0 -1 1% 12 19 99 22 8 99 22 8 0 0 0 0% 12 37 111 25 6 112 25 6 1 0 0 -0% 12 55 115 25 5 110 23 5 -5 -2 0 4% 38 1 502 74 576 497 73 570 -5 -1 -6 0% 38 19 426 78 48 373 76 39 -53 -2 -9 12% 38 37 544 83 36 547 82 36 3 -1 0 -0% 38 55 501 77 23 511 80 24 10 3 1 -1% 64 1 917 125 1042 890 124 1014 -27 -1 -28 2% 64 19 1118 138 119 965 141 103 -153 3 -16 13% 64 37 1202 151 94 1136 150 81 -66 -1 -13 5% 64 55 1118 141 61 1072 140 58 -46 -1 -3 4% 90 1 1342 177 1519 1275 174 1450 -67 -3 -69 4% 90 19 2392 199 192 2116 189 176 -276 -10 -16 11% 90 37 3313 238 175 2972 225 145 -341 -13 -30 10% 90 55 1948 210 104 1843 213 100 -105 3 -4 5% Notes: 1) This test ran a memory hog program that started a specified number N of threads, and had each thread allocate and touch 1/N'th of the total memory to be used in the test run in a single loop, writing a constant word to memory, one store every 4096 bytes. Watching this test during some earlier trial runs, I would see each of these threads sit down on one CPU and stay there, for the remainder of the pass, a different CPU for each thread. 2) The 'real' column is not comparable to the 'sys' or 'user' columns. The 'real' column is seconds wall clock time elapsed, from beginning to end of that test pass. The 'sys' and 'user' columns are total CPU seconds spent on that test pass. For a 19 thread test run, for example, the sum of 'sys' and 'user' could be up to 19 times the number of 'real' elapsed wall clock seconds. 3) Tests were run on a fresh, single-user boot, to minimize the amount of memory already in use at the start of the test, and to minimize the amount of background activity that might interfere. 4) Tests were done on a 56 CPU, 28 Node system with 96 GBytes of RAM. 5) Notice that the 'real' time gets large for the single thread runs, even though the measured 'sys' and 'user' times are modest. I'm not sure what that means - probably something to do with it being slow for one thread to be accessing memory along ways away. Perhaps the fake numa system, running ostensibly the same workload, would not show this substantial degradation of 'real' time for one thread on many nodes -- lets hope not. 6) The high thread count passes (one thread per CPU - on 55 of 56 CPUs) ran quite efficiently, as one might expect. Each pair of threads needed to allocate and touch the memory on the node the two threads shared, a pleasantly parallizable workload. 7) The intermediate thread count passes, when asking for alot of memory forcing them to go to a few neighboring nodes, improved the most with this zonelist caching patch. Conclusions: * This zonelist cache patch probably makes little difference one way or the other for most workloads on real numa hardware, if those workloads avoid heavy off node allocations. * For memory intensive workloads requiring substantial off-node allocations on real numa hardware, this patch improves both kernel and elapsed timings up to ten per-cent. * For fake numa systems, I'm optimistic, but will have to leave that up to Rohit Seth to actually test (once I get him a 2.6.18 backport.) Signed-off-by: Paul Jackson <pj@sgi.com> Cc: Rohit Seth <rohitseth@google.com> Cc: Christoph Lameter <clameter@engr.sgi.com> Cc: David Rientjes <rientjes@cs.washington.edu> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Get rid of zone_table[]Christoph Lameter2006-12-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The zone table is mostly not needed. If we have a node in the page flags then we can get to the zone via NODE_DATA() which is much more likely to be already in the cpu cache. In case of SMP and UP NODE_DATA() is a constant pointer which allows us to access an exact replica of zonetable in the node_zones field. In all of the above cases there will be no need at all for the zone table. The only remaining case is if in a NUMA system the node numbers do not fit into the page flags. In that case we make sparse generate a table that maps sections to nodes and use that table to to figure out the node number. This table is sized to fit in a single cache line for the known 32 bit NUMA platform which makes it very likely that the information can be obtained without a cache miss. For sparsemem the zone table seems to be have been fairly large based on the maximum possible number of sections and the number of zones per node. There is some memory saving by removing zone_table. The main benefit is to reduce the cache foootprint of the VM from the frequent lookups of zones. Plus it simplifies the page allocator. [akpm@osdl.org: build fix] Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] __unmap_hugepage_range(): add commentChen, Kenneth W2006-12-07
| | | | | | | | Signed-off-by: Ken Chen <kenneth.w.chen@intel.com> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] memory page alloc minor cleanupsPaul Jackson2006-12-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - s/freeliest/freelist/ spelling fix - Check for NULL *z zone seems useless - even if it could happen, so what? Perhaps we should have a check later on if we are faced with an allocation request that is not allowed to fail - shouldn't that be a serious kernel error, passing an empty zonelist with a mandate to not fail? - Initializing 'z' to zonelist->zones can wait until after the first get_page_from_freelist() fails; we only use 'z' in the wakeup_kswapd() loop, so let's initialize 'z' there, in a 'for' loop. Seems clearer. - Remove superfluous braces around a break - Fix a couple errant spaces - Adjust indentation on the cpuset_zone_allowed() check, to match the lines just before it -- seems easier to read in this case. - Add another set of braces to the zone_watermark_ok logic From: Paul Jackson <pj@sgi.com> Backout one item from a previous "memory page_alloc minor cleanups" patch. Until and unless we are certain that no one can ever pass an empty zonelist to __alloc_pages(), this check for an empty zonelist (or some BUG equivalent) is essential. The code in get_page_from_freelist() blow ups if passed an empty zonelist. Signed-off-by: Paul Jackson <pj@sgi.com> Acked-by: Christoph Lameter <clameter@sgi.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Merge git://git.infradead.org/users/dhowells/workq-2.6Linus Torvalds2006-12-06
|\ | | | | | | | | | | | | | | | | | | | | * git://git.infradead.org/users/dhowells/workq-2.6: Actually update the fixed up compile failures. WorkQueue: Fix up arch-specific work items where possible WorkStruct: make allyesconfig WorkStruct: Pass the work_struct pointer instead of context data WorkStruct: Merge the pending bit into the wq_data pointer WorkStruct: Typedef the work function prototype WorkStruct: Separate delayable and non-delayable events.
| * Merge branch 'master' of ↵David Howells2006-12-05
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 Conflicts: drivers/ata/libata-scsi.c include/linux/libata.h Futher merge of Linus's head and compilation fixups. Signed-Off-By: David Howells <dhowells@redhat.com>
| * \ Merge branch 'master' of ↵David Howells2006-12-05
| |\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 Conflicts: drivers/infiniband/core/iwcm.c drivers/net/chelsio/cxgb2.c drivers/net/wireless/bcm43xx/bcm43xx_main.c drivers/net/wireless/prism54/islpci_eth.c drivers/usb/core/hub.h drivers/usb/input/hid-core.c net/core/netpoll.c Fix up merge failures with Linus's head and fix new compilation failures. Signed-Off-By: David Howells <dhowells@redhat.com>
| * | | WorkStruct: make allyesconfigDavid Howells2006-11-22
| | | | | | | | | | | | | | | | | | | | | | | | Fix up for make allyesconfig. Signed-Off-By: David Howells <dhowells@redhat.com>
| * | | WorkStruct: Pass the work_struct pointer instead of context dataDavid Howells2006-11-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pass the work_struct pointer to the work function rather than context data. The work function can use container_of() to work out the data. For the cases where the container of the work_struct may go away the moment the pending bit is cleared, it is made possible to defer the release of the structure by deferring the clearing of the pending bit. To make this work, an extra flag is introduced into the management side of the work_struct. This governs auto-release of the structure upon execution. Ordinarily, the work queue executor would release the work_struct for further scheduling or deallocation by clearing the pending bit prior to jumping to the work function. This means that, unless the driver makes some guarantee itself that the work_struct won't go away, the work function may not access anything else in the work_struct or its container lest they be deallocated.. This is a problem if the auxiliary data is taken away (as done by the last patch). However, if the pending bit is *not* cleared before jumping to the work function, then the work function *may* access the work_struct and its container with no problems. But then the work function must itself release the work_struct by calling work_release(). In most cases, automatic release is fine, so this is the default. Special initiators exist for the non-auto-release case (ending in _NAR). Signed-Off-By: David Howells <dhowells@redhat.com>
| * | | WorkStruct: Separate delayable and non-delayable events.David Howells2006-11-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Separate delayable work items from non-delayable work items be splitting them into a separate structure (delayed_work), which incorporates a work_struct and the timer_list removed from work_struct. The work_struct struct is huge, and this limits it's usefulness. On a 64-bit architecture it's nearly 100 bytes in size. This reduces that by half for the non-delayable type of event. Signed-Off-By: David Howells <dhowells@redhat.com>
* | | | [PATCH] uclinux: fix mmap() of directory for nommu caseMike Frysinger2006-12-06
| |_|/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I was playing with blackfin when i hit a neat bug ... doing an open() on a directory and then passing that fd to mmap() would cause the kernel to hang after poking into the code a bit more, i found that mm/nommu.c:validate_mmap_request() checks the length and if it is 0, just returns the address ... this is in stark contrast to mmu's mm/mmap.c:do_mmap_pgoff() where it returns -EINVAL for 0 length requests ... i then noticed that some other parts of the logic is out of date between the two funcs, so perhaps that's the easy fix ? Signed-off-by: Greg Ungerer <gerg@uclinux.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* | | [PATCH] Export should_remove_suid()Mark Fasheh2006-12-01
| |/ |/| | | | | | | | | This helps us avoid replicating the same logic within file system drivers. Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
* | [PATCH] x86_64: fix bad page state in process 'swapper'Mel Gorman2006-11-23
|/ | | | | | | | | | | | | | | | | | | find_min_pfn_for_node() and find_min_pfn_with_active_regions() both depend on a sorted early_node_map[]. However, sort_node_map() is being called after fin_min_pfn_with_active_regions() in free_area_init_nodes(). In most cases, this is ok, but on at least one x86_64, the SRAT table caused the E820 ranges to be registered out of order. This gave the wrong values for the min PFN range resulting in some pages not being initialised. This patch sorts the early_node_map in find_min_pfn_for_node(). It has been boot tested on x86, x86_64, ppc64 and ia64. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Andre Noll <maan@systemlinux.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Fix strange size check in __get_vm_area_node()OGAWA Hirofumi2006-11-16
| | | | | | | | | | | | | | | | | | | | Recently, __get_vm_area_node() was changed like following if (unlikely(!area)) return NULL; - if (unlikely(!size)) { - kfree (area); + if (unlikely(!size)) return NULL; - } It is leaking `area', also original code seems strange already. Probably, we wanted to do this patch. Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] hugetlb: fix error return for brk() entering a hugepage regionHugh Dickins2006-11-14
| | | | | | | | | | | Commit cb07c9a1864a8eac9f3123e428100d5b2a16e65a causes the wrong return value. is_hugepage_only_range() is a boolean, so we should return -EINVAL rather than 1. Also - we can use "mm" instead of looking up "current->mm" again. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] hugetlb: check for brk() entering a hugepage regionDavid Gibson2006-11-14
| | | | | | | | | | | | | | | | Unlike mmap(), the codepath for brk() creates a vma without first checking that it doesn't touch a region exclusively reserved for hugepages. On powerpc, this can allow it to create a normal page vma in a hugepage region, causing oopses and other badness. Add a test to prevent this. With this patch, brk() will simply fail if it attempts to move the break into a hugepage reserved region. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Cc: Adam Litke <agl@us.ibm.com> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] hugetlb: prepare_hugepage_range check offset tooHugh Dickins2006-11-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | (David:) If hugetlbfs_file_mmap() returns a failure to do_mmap_pgoff() - for example, because the given file offset is not hugepage aligned - then do_mmap_pgoff will go to the unmap_and_free_vma backout path. But at this stage the vma hasn't been marked as hugepage, and the backout path will call unmap_region() on it. That will eventually call down to the non-hugepage version of unmap_page_range(). On ppc64, at least, that will cause serious problems if there are any existing hugepage pagetable entries in the vicinity - for example if there are any other hugepage mappings under the same PUD. unmap_page_range() will trigger a bad_pud() on the hugepage pud entries. I suspect this will also cause bad problems on ia64, though I don't have a machine to test it on. (Hugh:) prepare_hugepage_range() should check file offset alignment when it checks virtual address and length, to stop MAP_FIXED with a bad huge offset from unmapping before it fails further down. PowerPC should apply the same prepare_hugepage_range alignment checks as ia64 and all the others do. Then none of the alignment checks in hugetlbfs_file_mmap are required (nor is the check for too small a mapping); but even so, move up setting of VM_HUGETLB and add a comment to warn of what David Gibson discovered - if hugetlbfs_file_mmap fails before setting it, do_mmap_pgoff's unmap_region when unwinding from error will go the non-huge way, which may cause bad behaviour on architectures (powerpc and ia64) which segregate their huge mappings into a separate region of the address space. Signed-off-by: Hugh Dickins <hugh@veritas.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: "David S. Miller" <davem@davemloft.net> Acked-by: Adam Litke <agl@us.ibm.com> Acked-by: David Gibson <david@gibson.dropbear.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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