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* kmemleak: Allow the early log buffer to be configurable.Catalin Marinas2009-06-251-0/+12
| | | | | | | | | | | | | (feature suggested by Sergey Senozhatsky) Kmemleak needs to track all the memory allocations but some of these happen before kmemleak is initialised. These are stored in an internal buffer which may be exceeded in some kernel configurations. This patch adds a configuration option with a default value of 400 and also removes the stack dump when the early log buffer is exceeded. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Sergey Senozhatsky <sergey.senozhatsky@mail.by>
* kmemleak: Do not force the slab debugging Kconfig optionsCatalin Marinas2009-06-231-2/+3
| | | | | | | | | | | Selecting DEBUG_SLAB or SLUB_DEBUG by the KMEMLEAK menu entry may cause issues with other dependencies (KMEMCHECK). These configuration options aren't strictly needed by kmemleak but they may increase the chances of finding leaks. This patch also updates the KMEMLEAK config entry help text. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
* Merge branch 'core-fixes-for-linus' of ↵Linus Torvalds2009-06-211-1/+1
|\ | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: lockdep: Select frame pointers on x86 dma-debug: be more careful when building reference entries dma-debug: check for sg_call_ents in best-fit algorithm too
| * lockdep: Select frame pointers on x86Peter Zijlstra2009-06-211-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | x86 stack traces are a piece of crap without frame pointers, and its not like the 'performance gain' of not having stack pointers matters when you selected lockdep. Reported-by: Andrew Morton <akpm@linux-foundation.org> LKML-Reference: <new-submission> Cc: <stable@kernel.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | kmemcheck: make kconfig accessible for other architecturesPekka Enberg2009-06-151-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | The Kconfig options of kmemcheck are hidden under arch/x86 which makes porting to other architectures harder. To fix that, move the Kconfig bits to lib/Kconfig.kmemcheck and introduce a CONFIG_HAVE_ARCH_KMEMCHECK config option that architectures can define. Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi> [rebased for mainline inclusion] Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
* | kmemcheck: enable in the x86 KconfigVegard Nossum2009-06-151-2/+2
| | | | | | | | | | | | | | | | | | | | let it rip! Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Ingo Molnar <mingo@elte.hu> [rebased for mainline inclusion] Signed-off-by: Vegard Nossum <vegardno@ifi.uio.no>
* | kmemleak: Simple testing module for kmemleakCatalin Marinas2009-06-111-0/+10
| | | | | | | | | | | | | | This patch adds a loadable module that deliberately leaks memory. It is used for testing various memory leaking scenarios. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* | kmemleak: Enable the building of the memory leak detectorCatalin Marinas2009-06-111-0/+22
|/ | | | | | | This patch adds the Kconfig.debug and Makefile entries needed for building kmemleak into the kernel. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* Remove old PRINTK_DEBUG config itemJason Baron2009-05-081-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | On Tue, Apr 21, 2009 at 01:55:53PM +0200, Stefan Richter wrote: > Robert P. J. Day wrote: > > lib/Kconfig.debug: select PRINTK_DEBUG > > > > should that perhaps refer to "DYNAMIC_PRINTK_DEBUG"? since there is > > no such thing as a PRINTK_DEBUG Kconfig variable. > > Looks like a rudiment from an earlier version of Jason's "driver core: > basic infrastructure for per-module dynamic debug messages", > http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=346e15beb5343c2eb8216d820f2ed8f150822b08 > Search an LKML archive for '+#ifdef CONFIG_PRINTK_DEBUG'. > > Jason, should it be deleted or replaced by something? We re-named 'DYNAMIC_PRINTK_DEBUG' to 'DYNAMIC_DEBUG' in 2.6.30.... 'PRINTK_DEBUG' as pointed out never existed. So, it appears to be extraneous, and should be removed. thanks for pointing it out. Signed-off-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* [S390] omit frame pointers on s390 when possibleHeiko Carstens2009-04-231-4/+4
| | | | | | | | | | | | Always omit frame pointers on s390. They aren't too useful for the kernel since we have already the kernel stack backchain which allows us to walk the kernel stack. So eleminate the extra code for frame pointers. Only allow the extra code for the function tracer since the gcc compile options -pg and -fomit-frame-pointer are incompatible. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* Merge branch 'linus' into core/softlockupIngo Molnar2009-04-071-33/+55
|\ | | | | | | | | Conflicts: kernel/sysctl.c
| * generic debug pageallocAkinobu Mita2009-04-011-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | CONFIG_DEBUG_PAGEALLOC is now supported by x86, powerpc, sparc64, and s390. This patch implements it for the rest of the architectures by filling the pages with poison byte patterns after free_pages() and verifying the poison patterns before alloc_pages(). This generic one cannot detect invalid page accesses immediately but invalid read access may cause invalid dereference by poisoned memory and invalid write access can be detected after a long delay. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * Merge branch 'iommu-for-linus' of ↵Linus Torvalds2009-03-301-0/+11
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'iommu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (60 commits) dma-debug: make memory range checks more consistent dma-debug: warn of unmapping an invalid dma address dma-debug: fix dma_debug_add_bus() definition for !CONFIG_DMA_API_DEBUG dma-debug/x86: register pci bus for dma-debug leak detection dma-debug: add a check dma memory leaks dma-debug: add checks for kernel text and rodata dma-debug: print stacktrace of mapping path on unmap error dma-debug: Documentation update dma-debug: x86 architecture bindings dma-debug: add function to dump dma mappings dma-debug: add checks for sync_single_sg_* dma-debug: add checks for sync_single_range_* dma-debug: add checks for sync_single_* dma-debug: add checking for [alloc|free]_coherent dma-debug: add add checking for map/unmap_sg dma-debug: add checking for map/unmap_page/single dma-debug: add core checking functions dma-debug: add debugfs interface dma-debug: add kernel command line parameters dma-debug: add initialization code ... Fix trivial conflicts due to whitespace changes in arch/x86/kernel/pci-nommu.c
| | * Merge branch 'linus' into core/iommuIngo Molnar2009-03-281-32/+42
| | |\ | | | | | | | | | | | | | | | | Conflicts: arch/x86/Kconfig
| | * | dma-debug: add Kconfig entryJoerg Roedel2009-03-051-0/+11
| | | | | | | | | | | | | | | | | | | | | | | | Impact: add a Kconfig entry for DMA-API debugging Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
| * | | Merge branch 'origin' into develRussell King2009-03-281-32/+42
| |\ \ \ | | | |/ | | |/| | | | | | | | | Conflicts: sound/soc/pxa/pxa2xx-i2s.c
| | * | dynamic debug: update docsJason Baron2009-03-241-31/+41
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | updates the documentation for 'dynamic debug' feature. Signed-off-by: Greg Banks <gnb@sgi.com> Signed-off-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| | * | dynamic debug: combine dprintk and dynamic printkJason Baron2009-03-241-1/+1
| | |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch combines Greg Bank's dprintk() work with the existing dynamic printk patchset, we are now calling it 'dynamic debug'. The new feature of this patchset is a richer /debugfs control file interface, (an example output from my system is at the bottom), which allows fined grained control over the the debug output. The output can be controlled by function, file, module, format string, and line number. for example, enabled all debug messages in module 'nf_conntrack': echo -n 'module nf_conntrack +p' > /mnt/debugfs/dynamic_debug/control to disable them: echo -n 'module nf_conntrack -p' > /mnt/debugfs/dynamic_debug/control A further explanation can be found in the documentation patch. Signed-off-by: Greg Banks <gnb@sgi.com> Signed-off-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| * | Merge branch 'for-rmk' of git://git.pengutronix.de/git/imx/linux-2.6 into develRussell King2009-03-131-1/+1
| |\ \ | | |/ | | | | | | | | | | | | Conflicts: arch/arm/mach-at91/gpio.c
| | * docsrc: use config instead of menuconfigRandy Dunlap2009-02-201-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | BUILD_DOCSRC should be controlled by "config" instead of "menuconfig". I have no idea how I managed to use "menuconfig" here. Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | [ARM] 5386/2: unwind: Add Makefile and Kconfig entries for ARM stack unwindingCatalin Marinas2009-02-191-1/+1
| |/ | | | | | | | | | | | | | | | | This patch also makes the frame pointer default to y only if !ARM_UNWIND. LOCKDEP no longer selects FRAME_POINTER if ARM_UNWIND is enabled. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* | softlockup: make DETECT_HUNG_TASK default depend on DETECT_SOFTLOCKUPIngo Molnar2009-04-071-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | Don't offer a default-y option when the user has turned off CONFIG_DETECT_SOFTLOCKUP already. Do offer it as 'y' only if DETECT_SOFTLOCKUP is on already. This makes it match previous behavior - where the hung-task check was embedded i CONFIG_DETECT_SOFTLOCKUP code. Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | Merge branch 'linus' into core/softlockupIngo Molnar2009-02-121-13/+9
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| * Merge branch 'core-fixes-for-linus' of ↵Linus Torvalds2009-01-261-13/+0
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: debugobjects: add and use INIT_WORK_ON_STACK rcu: remove duplicate CONFIG_RCU_CPU_STALL_DETECTOR relay: fix lock imbalance in relay_late_setup_files oprofile: fix uninitialized use of struct op_entry rcu: move Kconfig menu softlock: fix false panic which can occur if softlockup_thresh is reduced rcu: add __cpuinit to rcu_init_percpu_data()
| | * rcu: remove duplicate CONFIG_RCU_CPU_STALL_DETECTORLai Jiangshan2009-01-221-13/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: remove the old CONFIG_RCU_CPU_STALL_DETECTOR tree_rcu introduce CONFIG_RCU_CPU_STALL_DETECTOR again. These two are the same exactly except: the old one "depends on CLASSIC_RCU" the new one "depends on CLASSIC_RCU || TREE_RCU" This patch remove the old one. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | x86: define ARCH_WANT_FRAME_POINTERSJeff Mahoney2009-01-181-0/+9
| |/ | | | | | | | | | | | | | | | | | | | | | | Commit da4276b8299a6544dc41ac2485d3ffca5811b3fb changed a dependency for FRAME_POINTER from X86 to ARCH_WANT_FRAME_POINTERS, but didn't actually define it. This patch adds the definition for ARCH_WANT_FRAME_POINTERS. Without it, FRAME_POINTER can't be enabled on x86. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | softlockup: decouple hung tasks check from softlockup detectionMandeep Singh Baines2009-01-161-0/+38
|/ | | | | | | | | | | | | | | | | | | | Decoupling allows: * hung tasks check to happen at very low priority * hung tasks check and softlockup to be enabled/disabled independently at compile and/or run-time * individual panic settings to be enabled disabled independently at compile and/or run-time * softlockup threshold to be reduced without increasing hung tasks poll frequency (hung task check is expensive relative to softlock watchdog) * hung task check to be zero over-head when disabled at run-time Signed-off-by: Mandeep Singh Baines <msb@google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'x86-fixes-for-linus' of ↵Linus Torvalds2009-01-101-8/+8
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (36 commits) x86: fix section mismatch warnings in mcheck/mce_amd_64.c x86: offer frame pointers in all build modes x86: remove duplicated #include's x86: k8 numa register active regions later x86: update Alan Cox's email addresses x86: rename all fields of mpc_table mpc_X to X x86: rename all fields of mpc_oemtable oem_X to X x86: rename all fields of mpc_bus mpc_X to X x86: rename all fields of mpc_cpu mpc_X to X x86: rename all fields of mpc_intsrc mpc_X to X x86: rename all fields of mpc_lintsrc mpc_X to X x86: rename all fields of mpc_iopic mpc_X to X x86: irqinit_64.c init_ISA_irqs should be static Documentation/x86/boot.txt: payload length was changed to payload_length x86: setup_percpu.c fix style problems x86: irqinit_64.c fix style problems x86: irqinit_32.c fix style problems x86: i8259.c fix style problems x86: irq_32.c fix style problems x86: ioport.c fix style problems ...
| * x86: offer frame pointers in all build modesIngo Molnar2009-01-071-8/+8
| | | | | | | | | | | | | | | | | | | | CONFIG_FRAME_POINTERS=y results in much better debug info for the kernel (clear and precise backtraces), with the only drawback being a ~1% increase in kernel size. So offer it unconditionally and enable it by default. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | NOMMU: Make VMAs per MM as for MMU-mode linuxDavid Howells2009-01-081-0/+7
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make VMAs per mm_struct as for MMU-mode linux. This solves two problems: (1) In SYSV SHM where nattch for a segment does not reflect the number of shmat's (and forks) done. (2) In mmap() where the VMA's vm_mm is set to point to the parent mm by an exec'ing process when VM_EXECUTABLE is specified, regardless of the fact that a VMA might be shared and already have its vm_mm assigned to another process or a dead process. A new struct (vm_region) is introduced to track a mapped region and to remember the circumstances under which it may be shared and the vm_list_struct structure is discarded as it's no longer required. This patch makes the following additional changes: (1) Regions are now allocated with alloc_pages() rather than kmalloc() and with no recourse to __GFP_COMP, so the pages are not composite. Instead, each page has a reference on it held by the region. Anything else that is interested in such a page will have to get a reference on it to retain it. When the pages are released due to unmapping, each page is passed to put_page() and will be freed when the page usage count reaches zero. (2) Excess pages are trimmed after an allocation as the allocation must be made as a power-of-2 quantity of pages. (3) VMAs are added to the parent MM's R/B tree and mmap lists. As an MM may end up with overlapping VMAs within the tree, the VMA struct address is appended to the sort key. (4) Non-anonymous VMAs are now added to the backing inode's prio list. (5) Holes may be punched in anonymous VMAs with munmap(), releasing parts of the backing region. The VMA and region structs will be split if necessary. (6) sys_shmdt() only releases one attachment to a SYSV IPC shared memory segment instead of all the attachments at that addresss. Multiple shmat()'s return the same address under NOMMU-mode instead of different virtual addresses as under MMU-mode. (7) Core dumping for ELF-FDPIC requires fewer exceptions for NOMMU-mode. (8) /proc/maps is now the global list of mapped regions, and may list bits that aren't actually mapped anywhere. (9) /proc/meminfo gains a line (tagged "MmapCopy") that indicates the amount of RAM currently allocated by mmap to hold mappable regions that can't be mapped directly. These are copies of the backing device or file if not anonymous. These changes make NOMMU mode more similar to MMU mode. The downside is that NOMMU mode requires some extra memory to track things over NOMMU without this patch (VMAs are no longer shared, and there are now region structs). Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Mike Frysinger <vapier.adi@gmail.com> Acked-by: Paul Mundt <lethal@linux-sh.org>
* Merge branch 'for-linus' of ↵Linus Torvalds2008-12-301-0/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6 * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6: slub: avoid leaking caches or refcounts on sysfs error slab: Fix comment on #endif slab: remove GFP_THISNODE clearing from alloc_slabmgmt() slub: Add might_sleep_if() to slab_alloc() SLUB: failslab support slub: Fix incorrect use of loose slab: Update the kmem_cache_create documentation regarding the name parameter slub: make early_kmem_cache_node_alloc void slab: unsigned slabp->inuse cannot be less than 0 slub - fix get_object_page comment SLUB: Replace __builtin_return_address(0) with _RET_IP_. SLUB: cleanup - define macros instead of hardcoded numbers
| * SLUB: failslab supportAkinobu Mita2008-12-291-0/+1
| | | | | | | | | | | | | | | | | | | | | | Currently fault-injection capability for SLAB allocator is only available to SLAB. This patch makes it available to SLUB, too. [penberg@cs.helsinki.fi: unify slab and slub implementations] Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Matt Mackall <mpm@selenic.com> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
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*---. \ Merge branches 'core/debugobjects', 'core/iommu', 'core/locking', ↵Ingo Molnar2008-12-251-0/+21
|\ \ \ \ | | | |/ | | |/| | | | | 'core/printk', 'core/rcu', 'core/resources', 'core/softirq' and 'core/stacktrace' into core/core
| | | * "Tree RCU": scalable classic RCU implementationPaul E. McKenney2008-12-181-0/+13
| | |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes a long-standing performance bug in classic RCU that results in massive internal-to-RCU lock contention on systems with more than a few hundred CPUs. Although this patch creates a separate flavor of RCU for ease of review and patch maintenance, it is intended to replace classic RCU. This patch still handles stress better than does mainline, so I am still calling it ready for inclusion. This patch is against the -tip tree. Nevertheless, experience on an actual 1000+ CPU machine would still be most welcome. Most of the changes noted below were found while creating an rcutiny (which should permit ejecting the current rcuclassic) and while doing detailed line-by-line documentation. Updates from v9 (http://lkml.org/lkml/2008/12/2/334): o Fixes from remainder of line-by-line code walkthrough, including comment spelling, initialization, undesirable narrowing due to type conversion, removing redundant memory barriers, removing redundant local-variable initialization, and removing redundant local variables. I do not believe that any of these fixes address the CPU-hotplug issues that Andi Kleen was seeing, but please do give it a whirl in case the machine is smarter than I am. A writeup from the walkthrough may be found at the following URL, in case you are suffering from terminal insomnia or masochism: http://www.kernel.org/pub/linux/kernel/people/paulmck/tmp/rcutree-walkthrough.2008.12.16a.pdf o Made rcutree tracing use seq_file, as suggested some time ago by Lai Jiangshan. o Added a .csv variant of the rcudata debugfs trace file, to allow people having thousands of CPUs to drop the data into a spreadsheet. Tested with oocalc and gnumeric. Updated documentation to suit. Updates from v8 (http://lkml.org/lkml/2008/11/15/139): o Fix a theoretical race between grace-period initialization and force_quiescent_state() that could occur if more than three jiffies were required to carry out the grace-period initialization. Which it might, if you had enough CPUs. o Apply Ingo's printk-standardization patch. o Substitute local variables for repeated accesses to global variables. o Fix comment misspellings and redundant (but harmless) increments of ->n_rcu_pending (this latter after having explicitly added it). o Apply checkpatch fixes. Updates from v7 (http://lkml.org/lkml/2008/10/10/291): o Fixed a number of problems noted by Gautham Shenoy, including the cpu-stall-detection bug that he was having difficulty convincing me was real. ;-) o Changed cpu-stall detection to wait for ten seconds rather than three in order to reduce false positive, as suggested by Ingo Molnar. o Produced a design document (http://lwn.net/Articles/305782/). The act of writing this document uncovered a number of both theoretical and "here and now" bugs as noted below. o Fix dynticks_nesting accounting confusion, simplify WARN_ON() condition, fix kerneldoc comments, and add memory barriers in dynticks interface functions. o Add more data to tracing. o Remove unused "rcu_barrier" field from rcu_data structure. o Count calls to rcu_pending() from scheduling-clock interrupt to use as a surrogate timebase should jiffies stop counting. o Fix a theoretical race between force_quiescent_state() and grace-period initialization. Yes, initialization does have to go on for some jiffies for this race to occur, but given enough CPUs... Updates from v6 (http://lkml.org/lkml/2008/9/23/448): o Fix a number of checkpatch.pl complaints. o Apply review comments from Ingo Molnar and Lai Jiangshan on the stall-detection code. o Fix several bugs in !CONFIG_SMP builds. o Fix a misspelled config-parameter name so that RCU now announces at boot time if stall detection is configured. o Run tests on numerous combinations of configurations parameters, which after the fixes above, now build and run correctly. Updates from v5 (http://lkml.org/lkml/2008/9/15/92, bad subject line): o Fix a compiler error in the !CONFIG_FANOUT_EXACT case (blew a changeset some time ago, and finally got around to retesting this option). o Fix some tracing bugs in rcupreempt that caused incorrect totals to be printed. o I now test with a more brutal random-selection online/offline script (attached). Probably more brutal than it needs to be on the people reading it as well, but so it goes. o A number of optimizations and usability improvements: o Make rcu_pending() ignore the grace-period timeout when there is no grace period in progress. o Make force_quiescent_state() avoid going for a global lock in the case where there is no grace period in progress. o Rearrange struct fields to improve struct layout. o Make call_rcu() initiate a grace period if RCU was idle, rather than waiting for the next scheduling clock interrupt. o Invoke rcu_irq_enter() and rcu_irq_exit() only when idle, as suggested by Andi Kleen. I still don't completely trust this change, and might back it out. o Make CONFIG_RCU_TRACE be the single config variable manipulated for all forms of RCU, instead of the prior confusion. o Document tracing files and formats for both rcupreempt and rcutree. Updates from v4 for those missing v5 given its bad subject line: o Separated dynticks interface so that NMIs and irqs call separate functions, greatly simplifying it. In particular, this code no longer requires a proof of correctness. ;-) o Separated dynticks state out into its own per-CPU structure, avoiding the duplicated accounting. o The case where a dynticks-idle CPU runs an irq handler that invokes call_rcu() is now correctly handled, forcing that CPU out of dynticks-idle mode. o Review comments have been applied (thank you all!!!). For but one example, fixed the dynticks-ordering issue that Manfred pointed out, saving me much debugging. ;-) o Adjusted rcuclassic and rcupreempt to handle dynticks changes. Attached is an updated patch to Classic RCU that applies a hierarchy, greatly reducing the contention on the top-level lock for large machines. This passes 10-hour concurrent rcutorture and online-offline testing on 128-CPU ppc64 without dynticks enabled, and exposes some timekeeping bugs in presence of dynticks (exciting working on a system where "sleep 1" hangs until interrupted...), which were fixed in the 2.6.27 kernel. It is getting more reliable than mainline by some measures, so the next version will be against -tip for inclusion. See also Manfred Spraul's recent patches (or his earlier work from 2004 at http://marc.info/?l=linux-kernel&m=108546384711797&w=2). We will converge onto a common patch in the fullness of time, but are currently exploring different regions of the design space. That said, I have already gratefully stolen quite a few of Manfred's ideas. This patch provides CONFIG_RCU_FANOUT, which controls the bushiness of the RCU hierarchy. Defaults to 32 on 32-bit machines and 64 on 64-bit machines. If CONFIG_NR_CPUS is less than CONFIG_RCU_FANOUT, there is no hierarchy. By default, the RCU initialization code will adjust CONFIG_RCU_FANOUT to balance the hierarchy, so strongly NUMA architectures may choose to set CONFIG_RCU_FANOUT_EXACT to disable this balancing, allowing the hierarchy to be exactly aligned to the underlying hardware. Up to two levels of hierarchy are permitted (in addition to the root node), allowing up to 16,384 CPUs on 32-bit systems and up to 262,144 CPUs on 64-bit systems. I just know that I am going to regret saying this, but this seems more than sufficient for the foreseeable future. (Some architectures might wish to set CONFIG_RCU_FANOUT=4, which would limit such architectures to 64 CPUs. If this becomes a real problem, additional levels can be added, but I doubt that it will make a significant difference on real hardware.) In the common case, a given CPU will manipulate its private rcu_data structure and the rcu_node structure that it shares with its immediate neighbors. This can reduce both lock and memory contention by multiple orders of magnitude, which should eliminate the need for the strange manipulations that are reported to be required when running Linux on very large systems. Some shortcomings: o More bugs will probably surface as a result of an ongoing line-by-line code inspection. Patches will be provided as required. o There are probably hangs, rcutorture failures, &c. Seems quite stable on a 128-CPU machine, but that is kind of small compared to 4096 CPUs. However, seems to do better than mainline. Patches will be provided as required. o The memory footprint of this version is several KB larger than rcuclassic. A separate UP-only rcutiny patch will be provided, which will reduce the memory footprint significantly, even compared to the old rcuclassic. One such patch passes light testing, and has a memory footprint smaller even than rcuclassic. Initial reaction from various embedded guys was "it is not worth it", so am putting it aside. Credits: o Manfred Spraul for ideas, review comments, and bugs spotted, as well as some good friendly competition. ;-) o Josh Triplett, Ingo Molnar, Peter Zijlstra, Mathieu Desnoyers, Lai Jiangshan, Andi Kleen, Andy Whitcroft, and Andrew Morton for reviews and comments. o Thomas Gleixner for much-needed help with some timer issues (see patches below). o Jon M. Tollefson, Tim Pepper, Andrew Theurer, Jose R. Santos, Andy Whitcroft, Darrick Wong, Nishanth Aravamudan, Anton Blanchard, Dave Kleikamp, and Nathan Lynch for keeping machines alive despite my heavy abuse^Wtesting. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | debugobjects: add boot parameter default valueIngo Molnar2008-11-261-0/+8
| |/ | | | | | | | | | | | | | | | | | | | | | | | | Impact: add .config driven boot parameter default value Right now debugobjects can only be activated if the debug_objects boot parameter is passed in via the boot command line. Make this more convenient (and randomizable) by also providing a .config method. Enable it by default. (DEBUG_OBJECTS itself is default-off) Signed-off-by: Ingo Molnar <mingo@elte.hu>
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*-. \ Merge branches 'core/debug', 'core/futexes', 'core/locking', 'core/rcu', ↵Ingo Molnar2008-11-241-0/+10
|\ \ \ | |_|/ |/| | | | | 'core/signal', 'core/urgent' and 'core/xen' into core/core
| * | Merge branch 'linus' into core/debugIngo Molnar2008-09-101-3/+3
| |\ \ | | |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: lib/vsprintf.c Manual merge: include/linux/kernel.h Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | debug: add notifier chain debuggingArjan van de Ven2008-09-101-0/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | during some development we suspected a case where we left something in a notifier chain that was from a module that was unloaded already... and that sort of thing is rather hard to track down. This patch adds a very simple sanity check (which isn't all that expensive) to make sure the notifier we're about to call is actually from either the kernel itself of from a still-loaded module, avoiding a hard-to-chase-down crash. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | block: add BIG FAT WARNING to CONFIG_DEBUG_BLOCK_EXT_DEVTTejun Heo2008-10-171-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | CONFIG_DEBUG_BLOCK_EXT_DEVT can break booting even on some modern distros. Add BIG FAT WARNING to keep people at a safe distance. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | | driver core: basic infrastructure for per-module dynamic debug messagesJason Baron2008-10-161-0/+55
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Base infrastructure to enable per-module debug messages. I've introduced CONFIG_DYNAMIC_PRINTK_DEBUG, which when enabled centralizes control of debugging statements on a per-module basis in one /proc file, currently, <debugfs>/dynamic_printk/modules. When, CONFIG_DYNAMIC_PRINTK_DEBUG, is not set, debugging statements can still be enabled as before, often by defining 'DEBUG' for the proper compilation unit. Thus, this patch set has no affect when CONFIG_DYNAMIC_PRINTK_DEBUG is not set. The infrastructure currently ties into all pr_debug() and dev_dbg() calls. That is, if CONFIG_DYNAMIC_PRINTK_DEBUG is set, all pr_debug() and dev_dbg() calls can be dynamically enabled/disabled on a per-module basis. Future plans include extending this functionality to subsystems, that define their own debug levels and flags. Usage: Dynamic debugging is controlled by the debugfs file, <debugfs>/dynamic_printk/modules. This file contains a list of the modules that can be enabled. The format of the file is as follows: <module_name> <enabled=0/1> . . . <module_name> : Name of the module in which the debug call resides <enabled=0/1> : whether the messages are enabled or not For example: snd_hda_intel enabled=0 fixup enabled=1 driver enabled=0 Enable a module: $echo "set enabled=1 <module_name>" > dynamic_printk/modules Disable a module: $echo "set enabled=0 <module_name>" > dynamic_printk/modules Enable all modules: $echo "set enabled=1 all" > dynamic_printk/modules Disable all modules: $echo "set enabled=0 all" > dynamic_printk/modules Finally, passing "dynamic_printk" at the command line enables debugging for all modules. This mode can be turned off via the above disable command. [gkh: minor cleanups and tweaks to make the build work quietly] Signed-off-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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*---. \ \ Merge branches 'x86/xen', 'x86/build', 'x86/microcode', 'x86/mm-debug-v2', ↵Ingo Molnar2008-10-121-0/+9
|\ \ \ \ \ | | |_|_|/ | |/| | | | | | | | 'x86/memory-corruption-check', 'x86/early-printk', 'x86/xsave', 'x86/ptrace-v2', 'x86/quirks', 'x86/setup', 'x86/spinlocks' and 'x86/signal' into x86/core-v2
| | * | | MM: virtual address debugJiri Slaby2008-06-191-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add some (configurable) expensive sanity checking to catch wrong address translations on x86. - create linux/mmdebug.h file to be able include this file in asm headers to not get unsolvable loops in header files - __phys_addr on x86_32 became a function in ioremap.c since PAGE_OFFSET, is_vmalloc_addr and VMALLOC_* non-constasts are undefined if declared in page_32.h - add __phys_addr_const for initializing doublefault_tss.__cr3 Tested on 386, 386pae, x86_64 and x86_64 numa=fake=2. Contains Andi's enable numa virtual address debug patch. Signed-off-by: Jiri Slaby <jirislaby@gmail.com> Cc: Andi Kleen <andi@firstfloor.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | | Merge branch 'rcu-v28-for-linus' of ↵Linus Torvalds2008-10-101-0/+13
|\ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'rcu-v28-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (21 commits) rcu: RCU-based detection of stalled CPUs for Classic RCU, fix rcu: RCU-based detection of stalled CPUs for Classic RCU rcu: add rcu_read_lock_sched() / rcu_read_unlock_sched() rcu: fix sparse shadowed variable warning doc/RCU: fix pseudocode in rcuref.txt rcuclassic: fix compiler warning rcu: use irq-safe locks rcuclassic: fix compilation NG rcu: fix locking cleanup fallout rcu: remove redundant ACCESS_ONCE definition from rcupreempt.c rcu: fix classic RCU locking cleanup lockdep problem rcu: trace fix possible mem-leak rcu: just rename call_rcu_bh instead of making it a macro rcu: remove list_for_each_rcu() rcu: fixes to include/linux/rcupreempt.h rcu: classic RCU locking and memory-barrier cleanups rcu: prevent console flood when one CPU sees another AWOL via RCU rcu, debug: detect stalled grace periods, cleanups rcu, debug: detect stalled grace periods rcu classic: new algorithm for callbacks-processing(v2) ...
| * | | | | rcu: RCU-based detection of stalled CPUs for Classic RCUPaul E. McKenney2008-10-031-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds stalled-CPU detection to Classic RCU. This capability is enabled by a new config variable CONFIG_RCU_CPU_STALL_DETECTOR, which defaults disabled. This is a debugging feature to detect infinite loops in kernel code, not something that non-kernel-hackers would be expected to care about. This feature can detect looping CPUs in !PREEMPT builds and looping CPUs with preemption disabled in PREEMPT builds. This is essentially a port of this functionality from the treercu patch, replacing the stall debug patch that is already in tip/core/rcu (commit 67182ae1c4). The changes from the patch in tip/core/rcu include making the config variable name match that in treercu, changing from seconds to jiffies to avoid spurious warnings, and printing a boot message when this feature is enabled. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | | | Merge commit 'v2.6.27-rc6' into core/rcuIngo Molnar2008-09-101-3/+20
| |\ \ \ \ \ | | |/ / / /
| * | | | | rcu, debug: detect stalled grace periodsPaul E. McKenney2008-08-111-0/+13
| | |_|/ / | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | this is a diagnostic patch for Classic RCU. The approach is to record a timestamp at the beginning of the grace period (in rcu_start_batch()), then have rcu_check_callbacks() complain if: 1. it is running on a CPU that has holding up grace periods for a long time (say one second). This will identify the culprit assuming that the culprit has not disabled hardware irqs, instruction execution, or some such. 2. it is running on a CPU that is not holding up grace periods, but grace periods have been held up for an even longer time (say two seconds). It is enabled via the default-off CONFIG_DEBUG_RCU_STALL kernel parameter. Rather than exponential backoff, it backs off to once per 30 seconds. My feeling upon thinking on it was that if you have stalled RCU grace periods for that long, a few extra printk() messages are probably the least of your worries... Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Yinghai Lu <yhlu.kernel@gmail.com> Cc: David Witbrodt <dawitbro@sbcglobal.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | | block: add fault injection mechanism for faking request timeoutsJens Axboe2008-10-091-1/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Only works for the generic request timer handling. Allows one to sporadically ignore request completions, thus exercising the timeout handling. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | | | | init: DEBUG_BLOCK_EXT_DEVT requires explicit root= paramTejun Heo2008-10-091-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | DEBUG_BLOCK_EXT_DEVT shuffles SCSI and IDE device numbers and root device number set using rdev become meaningless. Root devices should be explicitly specified using textual names. Warn about it if root can't be found and DEBUG_BLOCK_EXT_DEVT is enabled. Also, add warning to the help text. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | | | | Change default value of CONFIG_DEBUG_BLOCK_EXT_DEVT to 'n'Jens Axboe2008-10-091-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It's a debug option that you would explicitly enable to test this feature, we should default it to 'n' to prevent accidental surprises for now. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | | | | block: implement CONFIG_DEBUG_BLOCK_EXT_DEVTTejun Heo2008-10-091-0/+16
| |/ / / |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Extended devt introduces non-contiguos device numbers. This patch implements a debug option which forces most devt allocations to be from the extended area and spreads them out. This is enabled by default if DEBUG_KERNEL is set and achieves... 1. Detects code paths in kernel or userland which expect predetermined consecutive device numbers. 2. When something goes wrong, avoid corruption as adding to the minor of earlier partition won't lead to the wrong but valid device. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
generated by cgit v1.1 at 2024-10-31 05:29:57 +0000