- 06 10月, 2009 1 次提交
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由 Heiko Carstens 提交于
Also increase the maximum possible kmemleak early log entries since 2000 are not sufficient on s390. Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 20 9月, 2009 1 次提交
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由 Randy Dunlap 提交于
Sam suggested moving STRIP_ASM_SYMS into the Kernel hacking menu from the General Setup menu. It makes more sense there. Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
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- 02 9月, 2009 1 次提交
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由 David Howells 提交于
Add a config option (CONFIG_DEBUG_CREDENTIALS) to turn on some debug checking for credential management. The additional code keeps track of the number of pointers from task_structs to any given cred struct, and checks to see that this number never exceeds the usage count of the cred struct (which includes all references, not just those from task_structs). Furthermore, if SELinux is enabled, the code also checks that the security pointer in the cred struct is never seen to be invalid. This attempts to catch the bug whereby inode_has_perm() faults in an nfsd kernel thread on seeing cred->security be a NULL pointer (it appears that the credential struct has been previously released): http://www.kerneloops.org/oops.php?number=252883Signed-off-by: NDavid Howells <dhowells@redhat.com> Signed-off-by: NJames Morris <jmorris@namei.org>
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- 23 8月, 2009 2 次提交
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由 Paul E. McKenney 提交于
Now that CONFIG_TREE_PREEMPT_RCU is in place, there is no further need for CONFIG_PREEMPT_RCU. Remove it, along with whatever subtle bugs it may (or may not) contain. Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: josht@linux.vnet.ibm.com Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org LKML-Reference: <125097461396-git-send-email-> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Paul E. McKenney 提交于
Create a kernel/rcutree_plugin.h file that contains definitions for preemptable RCU (or, under the #else branch of the #ifdef, empty definitions for the classic non-preemptable semantics). These definitions fit into plugins defined in kernel/rcutree.c for this purpose. This variant of preemptable RCU uses a new algorithm whose read-side expense is roughly that of classic hierarchical RCU under CONFIG_PREEMPT. This new algorithm's update-side expense is similar to that of classic hierarchical RCU, and, in absence of read-side preemption or blocking, is exactly that of classic hierarchical RCU. Perhaps more important, this new algorithm has a much simpler implementation, saving well over 1,000 lines of code compared to mainline's implementation of preemptable RCU, which will hopefully be retired in favor of this new algorithm. The simplifications are obtained by maintaining per-task nesting state for running tasks, and using a simple lock-protected algorithm to handle accounting when tasks block within RCU read-side critical sections, making use of lessons learned while creating numerous user-level RCU implementations over the past 18 months. Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: josht@linux.vnet.ibm.com Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org LKML-Reference: <12509746134003-git-send-email-> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 20 8月, 2009 1 次提交
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由 Michael Ellerman 提交于
Very lightly tested, doesn't crash the kernel. Signed-off-by: NMichael Ellerman <michael@ellerman.id.au> Acked-by: NCatalin Marinas <catalin.marinas@arm.com> Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
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- 25 6月, 2009 1 次提交
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由 Catalin Marinas 提交于
(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: NCatalin Marinas <catalin.marinas@arm.com> Acked-by: NSergey Senozhatsky <sergey.senozhatsky@mail.by>
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- 24 6月, 2009 1 次提交
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由 Tejun Heo 提交于
Some archs (alpha and s390) need to use weak definitions for percpu variables in modules so that the compiler generates external references for them. This patch implements weak percpu definitions which arch can enable by defining ARCH_NEEDS_WEAK_PER_CPU in arch percpu header file. This weak definition adds the following two restrictions on percpu variable definitions. 1. percpu symbols must be unique whether static or not 2. percpu variables can't be defined inside a function To ensure that these restrictions are observed in generic code, config option DEBUG_FORCE_WEAK_PER_CPU enables weak percpu definitions for all cases. This patch is inspired by Ivan Kokshaysky's alpha percpu patch. [ Impact: stricter rules for percpu variables, one more debug config option ] Signed-off-by: NTejun Heo <tj@kernel.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: David Howells <dhowells@redhat.com> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
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- 23 6月, 2009 1 次提交
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由 Catalin Marinas 提交于
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: NCatalin Marinas <catalin.marinas@arm.com> Acked-by: NPekka Enberg <penberg@cs.helsinki.fi>
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- 21 6月, 2009 1 次提交
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由 Peter Zijlstra 提交于
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: NAndrew Morton <akpm@linux-foundation.org> LKML-Reference: <new-submission> Cc: <stable@kernel.org> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 15 6月, 2009 2 次提交
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由 Pekka Enberg 提交于
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: NPekka Enberg <penberg@cs.helsinki.fi> [rebased for mainline inclusion] Signed-off-by: NVegard Nossum <vegard.nossum@gmail.com>
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由 Vegard Nossum 提交于
let it rip! Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: NIngo Molnar <mingo@elte.hu> [rebased for mainline inclusion] Signed-off-by: NVegard Nossum <vegardno@ifi.uio.no>
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- 12 6月, 2009 2 次提交
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由 Catalin Marinas 提交于
This patch adds a loadable module that deliberately leaks memory. It is used for testing various memory leaking scenarios. Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
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由 Catalin Marinas 提交于
This patch adds the Kconfig.debug and Makefile entries needed for building kmemleak into the kernel. Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
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- 09 5月, 2009 1 次提交
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由 Jason Baron 提交于
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: NJason Baron <jbaron@redhat.com> Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
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- 23 4月, 2009 1 次提交
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由 Heiko Carstens 提交于
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: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
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- 07 4月, 2009 1 次提交
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由 Ingo Molnar 提交于
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: NIngo Molnar <mingo@elte.hu>
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- 01 4月, 2009 1 次提交
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由 Akinobu Mita 提交于
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: NAkinobu Mita <akinobu.mita@gmail.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 25 3月, 2009 2 次提交
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由 Jason Baron 提交于
updates the documentation for 'dynamic debug' feature. Signed-off-by: NGreg Banks <gnb@sgi.com> Signed-off-by: NJason Baron <jbaron@redhat.com> Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
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由 Jason Baron 提交于
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: NGreg Banks <gnb@sgi.com> Signed-off-by: NJason Baron <jbaron@redhat.com> Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
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- 05 3月, 2009 2 次提交
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由 Joerg Roedel 提交于
Impact: add a Kconfig entry for DMA-API debugging Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>
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由 Peter Zijlstra 提交于
Require framepointers for x86, because otherwise we'll be having empty stack traces, which is useless. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1236167295.5330.7240.camel@laptop> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 21 2月, 2009 1 次提交
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由 Randy Dunlap 提交于
BUILD_DOCSRC should be controlled by "config" instead of "menuconfig". I have no idea how I managed to use "menuconfig" here. Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 19 2月, 2009 1 次提交
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由 Catalin Marinas 提交于
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: NCatalin Marinas <catalin.marinas@arm.com> Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
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- 22 1月, 2009 1 次提交
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由 Lai Jiangshan 提交于
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: NLai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 19 1月, 2009 1 次提交
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由 Jeff Mahoney 提交于
Commit da4276b8 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: NJeff Mahoney <jeffm@suse.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 16 1月, 2009 1 次提交
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由 Mandeep Singh Baines 提交于
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: NMandeep Singh Baines <msb@google.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 08 1月, 2009 1 次提交
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由 David Howells 提交于
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: NDavid Howells <dhowells@redhat.com> Tested-by: NMike Frysinger <vapier.adi@gmail.com> Acked-by: NPaul Mundt <lethal@linux-sh.org>
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- 07 1月, 2009 1 次提交
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由 Ingo Molnar 提交于
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: NIngo Molnar <mingo@elte.hu>
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- 30 12月, 2008 1 次提交
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由 Frederic Weisbecker 提交于
Impact: new tracer plugin This patch adapts kmemtrace raw events tracing to the unified tracing API. To enable and use this tracer, just do the following: echo kmemtrace > /debugfs/tracing/current_tracer cat /debugfs/tracing/trace You will have the following output: # tracer: kmemtrace # # # ALLOC TYPE REQ GIVEN FLAGS POINTER NODE CALLER # FREE | | | | | | | | # | type_id 1 call_site 18446744071565527833 ptr 18446612134395152256 type_id 0 call_site 18446744071565585597 ptr 18446612134405955584 bytes_req 4096 bytes_alloc 4096 gfp_flags 208 node -1 type_id 1 call_site 18446744071565585534 ptr 18446612134405955584 type_id 0 call_site 18446744071565585597 ptr 18446612134405955584 bytes_req 4096 bytes_alloc 4096 gfp_flags 208 node -1 type_id 0 call_site 18446744071565636711 ptr 18446612134345164672 bytes_req 240 bytes_alloc 240 gfp_flags 208 node -1 type_id 1 call_site 18446744071565585534 ptr 18446612134405955584 type_id 0 call_site 18446744071565585597 ptr 18446612134405955584 bytes_req 4096 bytes_alloc 4096 gfp_flags 208 node -1 type_id 0 call_site 18446744071565636711 ptr 18446612134345164912 bytes_req 240 bytes_alloc 240 gfp_flags 208 node -1 type_id 1 call_site 18446744071565585534 ptr 18446612134405955584 type_id 0 call_site 18446744071565585597 ptr 18446612134405955584 bytes_req 4096 bytes_alloc 4096 gfp_flags 208 node -1 type_id 0 call_site 18446744071565636711 ptr 18446612134345165152 bytes_req 240 bytes_alloc 240 gfp_flags 208 node -1 type_id 0 call_site 18446744071566144042 ptr 18446612134346191680 bytes_req 1304 bytes_alloc 1312 gfp_flags 208 node -1 type_id 1 call_site 18446744071565585534 ptr 18446612134405955584 type_id 0 call_site 18446744071565585597 ptr 18446612134405955584 bytes_req 4096 bytes_alloc 4096 gfp_flags 208 node -1 type_id 1 call_site 18446744071565585534 ptr 18446612134405955584 That was to stay backward compatible with the format output produced in inux/tracepoint.h. This is the default ouput, but note that I tried something else. If you change an option: echo kmem_minimalistic > /debugfs/trace_options and then cat /debugfs/trace, you will have the following output: # tracer: kmemtrace # # # ALLOC TYPE REQ GIVEN FLAGS POINTER NODE CALLER # FREE | | | | | | | | # | - C 0xffff88007c088780 file_free_rcu + K 4096 4096 000000d0 0xffff88007cad6000 -1 getname - C 0xffff88007cad6000 putname + K 4096 4096 000000d0 0xffff88007cad6000 -1 getname + K 240 240 000000d0 0xffff8800790dc780 -1 d_alloc - C 0xffff88007cad6000 putname + K 4096 4096 000000d0 0xffff88007cad6000 -1 getname + K 240 240 000000d0 0xffff8800790dc870 -1 d_alloc - C 0xffff88007cad6000 putname + K 4096 4096 000000d0 0xffff88007cad6000 -1 getname + K 240 240 000000d0 0xffff8800790dc960 -1 d_alloc + K 1304 1312 000000d0 0xffff8800791d7340 -1 reiserfs_alloc_inode - C 0xffff88007cad6000 putname + K 4096 4096 000000d0 0xffff88007cad6000 -1 getname - C 0xffff88007cad6000 putname + K 992 1000 000000d0 0xffff880079045b58 -1 alloc_inode + K 768 1024 000080d0 0xffff88007c096400 -1 alloc_pipe_info + K 240 240 000000d0 0xffff8800790dca50 -1 d_alloc + K 272 320 000080d0 0xffff88007c088780 -1 get_empty_filp + K 272 320 000080d0 0xffff88007c088000 -1 get_empty_filp Yeah I shall confess kmem_minimalistic should be: kmem_alternative. Whatever, I find it more readable but this a personal opinion of course. We can drop it if you want. On the ALLOC/FREE column, + means an allocation and - a free. On the type column, you have K = kmalloc, C = cache, P = page I would like the flags to be GFP_* strings but that would not be easy to not break the column with strings.... About the node...it seems to always be -1. I don't know why but that shouldn't be difficult to find. I moved linux/tracepoint.h to trace/tracepoint.h as well. I think that would be more easy to find the tracer headers if they are all in their common directory. Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 29 12月, 2008 3 次提交
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由 Pekka Enberg 提交于
Users can pass kmemtrace.enabled=yes as a kernel parameter to enable kmemtrace at boot so remove the useless CONFIG_KMEMTRACE_DEFAULT_ENABLED config option. Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro> Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi>
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kmemtrace provides tracing for slab allocator functions, such as kmalloc, kfree, kmem_cache_alloc, kmem_cache_free etc.. Collected data is then fed to the userspace application in order to analyse allocation hotspots, internal fragmentation and so on, making it possible to see how well an allocator performs, as well as debug and profile kernel code. Signed-off-by: NEduard - Gabriel Munteanu <eduard.munteanu@linux360.ro> Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi>
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由 Akinobu Mita 提交于
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: NAkinobu Mita <akinobu.mita@gmail.com> Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi>
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- 19 12月, 2008 1 次提交
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由 Paul E. McKenney 提交于
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: NPaul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 26 11月, 2008 1 次提交
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由 Ingo Molnar 提交于
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: NIngo Molnar <mingo@elte.hu>
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- 17 10月, 2008 2 次提交
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由 Tejun Heo 提交于
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: NTejun Heo <tj@kernel.org> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Jason Baron 提交于
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: NJason Baron <jbaron@redhat.com> Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
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- 09 10月, 2008 3 次提交
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由 Jens Axboe 提交于
Only works for the generic request timer handling. Allows one to sporadically ignore request completions, thus exercising the timeout handling. Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Tejun Heo 提交于
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: NTejun Heo <tj@kernel.org> Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Jens Axboe 提交于
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: NJens Axboe <jens.axboe@oracle.com>
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