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* Optimize the ordering of sections in RW_DATA_SECTION.Tim Abbott2009-09-241-2/+2
| | | | | | | | | | | | | | The old RW_DATA_SECTION had INIT_TASK_DATA (which was more-than-PAGE_SIZE-aligned), followed by a bunch of small alignment stuff, followed by more PAGE_SIZE-aligned stuff, so you wasted memory in the middle of .data re-aligning back up to PAGE_SIZE. This patch sorts the sections by alignment requirements, which should pack them essentially optimally. Signed-off-by: Tim Abbott <tabbott@ksplice.com> Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'linus' into tracing/coreIngo Molnar2009-09-171-5/+19
|\ | | | | | | | | | | Merge reason: Pick up kernel/softirq.c update for dependent fix. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * Merge branch 'percpu-for-linus' into percpu-for-nextTejun Heo2009-08-141-16/+15
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: arch/sparc/kernel/smp_64.c arch/x86/kernel/cpu/perf_counter.c arch/x86/kernel/setup_percpu.c drivers/cpufreq/cpufreq_ondemand.c mm/percpu.c Conflicts in core and arch percpu codes are mostly from commit ed78e1e078dd44249f88b1dd8c76dafb39567161 which substituted many num_possible_cpus() with nr_cpu_ids. As for-next branch has moved all the first chunk allocators into mm/percpu.c, the changes are moved from arch code to mm/percpu.c. Signed-off-by: Tejun Heo <tj@kernel.org>
| * | linker script: unify usage of discard definitionTejun Heo2009-07-091-6/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Discarded sections in different archs share some commonality but have considerable differences. This led to linker script for each arch implementing its own /DISCARD/ definition, which makes maintaining tedious and adding new entries error-prone. This patch makes all linker scripts to move discard definitions to the end of the linker script and use the common DISCARDS macro. As ld uses the first matching section definition, archs can include default discarded sections by including them earlier in the linker script. ia64 is notable because it first throws away some ia64 specific subsections and then include the rest of the sections into the final image, so those sections must be discarded before the inclusion. defconfig compile tested for x86, x86-64, powerpc, powerpc64, ia64, alpha, sparc, sparc64 and s390. Michal Simek tested microblaze. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Paul Mundt <lethal@linux-sh.org> Acked-by: Mike Frysinger <vapier@gentoo.org> Tested-by: Michal Simek <monstr@monstr.eu> Cc: linux-arch@vger.kernel.org Cc: Michal Simek <monstr@monstr.eu> Cc: microblaze-uclinux@itee.uq.edu.au Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Tony Luck <tony.luck@intel.com>
| * | Merge branch 'master' into for-nextTejun Heo2009-07-041-2/+3
| |\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull linus#master to merge PER_CPU_DEF_ATTRIBUTES and alpha build fix changes. As alpha in percpu tree uses 'weak' attribute instead of inline assembly, there's no need for __used attribute. Conflicts: arch/alpha/include/asm/percpu.h arch/mn10300/kernel/vmlinux.lds.S include/linux/percpu-defs.h
| * | | linker script: throw away .discard sectionTejun Heo2009-06-241-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | x86 throws away .discard section but no other archs do. Also, .discard is not thrown away while linking modules. Make every arch and module linking throw it away. This will be used to define dummy variables for percpu declarations and definitions. This patch is based on Ivan Kokshaysky's alpha percpu patch. [ Impact: always throw away everything in .discard ] Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Richard Henderson <rth@twiddle.net> Cc: Russell King <linux@arm.linux.org.uk> Cc: Haavard Skinnemoen <hskinnemoen@atmel.com> Cc: Bryan Wu <cooloney@kernel.org> Cc: Mikael Starvik <starvik@axis.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: David Howells <dhowells@redhat.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Tony Luck <tony.luck@intel.com> Cc: Hirokazu Takata <takata@linux-m32r.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Michal Simek <monstr@monstr.eu> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: David S. Miller <davem@davemloft.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Chris Zankel <chris@zankel.net> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Ingo Molnar <mingo@elte.hu>
* | | | ftrace: __start_mcount_loc should be .init.rodataJohn Reiser2009-09-121-2/+3
| |_|/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | __start_mcount_loc[] is unused after init, yet occupies RAM forever as part of .rodata. 152kiB is typical on a 64-bit architecture. Instead, __start_mcount_loc should be in the interval [__init_begin, __init_end) so that the space is reclaimed after init. __start_mcount_loc[] is generated during the load portion of kernel build, and is used only by ftrace_init(). ftrace_init is declared '__init' and is in .init.text, which is freed after init. __start_mcount_loc is placed into .rodata by a call to MCOUNT_REC inside the RO_DATA macro of include/asm-generic/vmlinux.lds.h. The array *is* read-only, but more importantly it is not used after init. So the call to MCOUNT_REC should be moved from RO_DATA to INIT_DATA. This patch has been tested on x86_64 with CONFIG_DEBUG_PAGEALLOC=y which verifies that the address range never is accessed after init. Signed-off-by: John Reiser <jreiser@BitWagon.com> LKML-Reference: <4A6DF0B6.7080402@bitwagon.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | | vmlinux.lds.h: restructure BSS linker script macrosTim Abbott2009-07-181-10/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The BSS section macros in vmlinux.lds.h currently place the .sbss input section outside the bounds of [__bss_start, __bss_end]. On all architectures except for microblaze that handle both .sbss and __bss_start/__bss_end, this is wrong: the .sbss input section is within the range [__bss_start, __bss_end]. Relatedly, the example code at the top of the file actually has __bss_start/__bss_end defined twice; I believe the right fix here is to define them in the BSS_SECTION macro but not in the BSS macro. Another problem with the current macros is that several architectures have an ALIGN(4) or some other small number just before __bss_stop in their linker scripts. The BSS_SECTION macro currently hardcodes this to 4; while it should really be an argument. It also ignores its sbss_align argument; fix that. mn10300 is the only user at present of any of the macros touched by this patch. It looks like mn10300 actually was incorrectly converted to use the new BSS() macro (the alignment of 4 prior to conversion was a __bss_stop alignment, but the argument to the BSS macro is a start alignment). So fix this as well. I'd like acks from Sam and David on this one. Also CCing Paul, since he has a patch from me which will need to be updated to use BSS_SECTION(0, PAGE_SIZE, 4) once this gets merged. Signed-off-by: Tim Abbott <tabbott@ksplice.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
* | | Merge git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild-fixesLinus Torvalds2009-07-041-6/+6
|\ \ \ | |_|/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild-fixes: kbuild: finally remove the obsolete variable $TOPDIR gitignore: ignore scripts/ihex2fw Kbuild: Disable the -Wformat-security gcc flag gitignore: ignore gcov output files kbuild: deb-pkg ship changelog Add new __init_task_data macro to be used in arch init_task.c files. asm-generic/vmlinux.lds.h: shuffle INIT_TASK* macro names in vmlinux.lds.h Add new macros for page-aligned data and bss sections. asm-generic/vmlinux.lds.h: Fix up RW_DATA_SECTION definition.
| * | asm-generic/vmlinux.lds.h: shuffle INIT_TASK* macro names in vmlinux.lds.hTim Abbott2009-06-271-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We recently added a INIT_TASK(align) in include/asm-generic/vmlinux.lds.h, but there is already a macro INIT_TASK in include/linux/init_task.h, which is quite confusing. We should switch the macro in the linker script to INIT_TASK_DATA. (Sorry that I missed this in reviewing the patch). Since the macros are new, there is only one user of the INIT_TASK in vmlinux.lds.h, arch/mn10300/kernel/vmlinux.lds.S. However, we are currently using INIT_TASK_DATA for laying down an entire .data.init_task section. So rename that to INIT_TASK_DATA_SECTION. I would be worried about changing the meaning of INIT_TASK_DATA, but the old INIT_TASK_DATA implementation had no users, and in fact if anyone had tried to use it, it would have failed to compile because it didn't pass the alignment to the old INIT_TASK. Signed-off-by: Tim Abbott <tabbott@ksplice.com> Cc: David Howells <dhowells@redhat.com> Cc: Jesper Nilsson <Jesper.Nilsson@axis.com Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
| * | asm-generic/vmlinux.lds.h: Fix up RW_DATA_SECTION definition.Paul Mundt2009-06-261-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | RW_DATA_SECTION is defined to take 4 different alignment parameters, while NOSAVE_DATA currently uses a fixed PAGE_SIZE alignment as noted in the comments. There are presently no in-tree users of this at present, and I just stumbled across this while implementing the simplified script on a new architecture port, which subsequently resulted in a syntax error. Signed-off-by: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
* | | gcov: fix __ctors_start alignmentHeiko Carstens2009-06-301-1/+2
|/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The ctors section for each object file is eight byte aligned (on 64 bit). However the __ctors_start symbol starts at an arbitrary address dependent on the size of the previous sections. Therefore the linker may add some zeroes after __ctors_start to make sure the ctors contents are properly aligned. However the extra zeroes at the beginning aren't expected by the code. When walking the functions pointers contained in there and extra zeroes are added this may result in random jumps. So make sure that the __ctors_start symbol is always aligned as well. Fixes this crash on an allyesconfig on s390: [ 0.582482] Kernel BUG at 0000000000000012 [verbose debug info unavailable] [ 0.582489] illegal operation: 0001 [#1] SMP DEBUG_PAGEALLOC [ 0.582496] Modules linked in: [ 0.582501] CPU: 0 Tainted: G W 2.6.31-rc1-dirty #273 [ 0.582506] Process swapper (pid: 1, task: 000000003f218000, ksp: 000000003f2238e8) [ 0.582510] Krnl PSW : 0704200180000000 0000000000000012 (0x12) [ 0.582518] R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:0 CC:2 PM:0 EA:3 [ 0.582524] Krnl GPRS: 0000000000036727 0000000000000010 0000000000000001 0000000000000001 [ 0.582529] 00000000001dfefa 0000000000000000 0000000000000000 0000000000000040 [ 0.582534] 0000000001fff0f0 0000000001790628 0000000002296048 0000000002296048 [ 0.582540] 00000000020c438e 0000000001786000 0000000002014a66 000000003f223e60 [ 0.582553] Krnl Code:>0000000000000012: 0000 unknown [ 0.582559] 0000000000000014: 0000 unknown [ 0.582564] 0000000000000016: 0000 unknown [ 0.582570] 0000000000000018: 0000 unknown [ 0.582575] 000000000000001a: 0000 unknown [ 0.582580] 000000000000001c: 0000 unknown [ 0.582585] 000000000000001e: 0000 unknown [ 0.582591] 0000000000000020: 0000 unknown [ 0.582596] Call Trace: [ 0.582599] ([<0000000002014a46>] kernel_init+0x622/0x7a0) [ 0.582607] [<0000000000113e22>] kernel_thread_starter+0x6/0xc [ 0.582615] [<0000000000113e1c>] kernel_thread_starter+0x0/0xc [ 0.582621] INFO: lockdep is turned off. [ 0.582624] Last Breaking-Event-Address: [ 0.582627] [<0000000002014a64>] kernel_init+0x640/0x7a0 Cc: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* / LDSCRIPT: Name INIT_RAM_FS consistentlyDavid Howells2009-06-221-1/+1
|/ | | | | | | | | | | | | | In asm-generic/vmlinux.lds.h, name INIT_RAM_FS consistently, no matter the setting of CONFIG_BLK_DEV_INITRD. This corrects: commit ef53dae8658cf0e93d380983824a661067948d87 Author: Sam Ravnborg <sam@ravnborg.org> Date: Sun Jun 7 20:46:37 2009 +0200 Subject: Improve vmlinux.lds.h support for arch specific linker scripts Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel: constructor supportPeter Oberparleiter2009-06-181-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | Call constructors (gcc-generated initcall-like functions) during kernel start and module load. Constructors are e.g. used for gcov data initialization. Disable constructor support for usermode Linux to prevent conflicts with host glibc. Signed-off-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: WANG Cong <xiyou.wangcong@gmail.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Jeff Dike <jdike@addtoit.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Huang Ying <ying.huang@intel.com> Cc: Li Wei <W.Li@Sun.COM> Cc: Michael Ellerman <michaele@au1.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Heiko Carstens <heicars2@linux.vnet.ibm.com> Cc: Martin Schwidefsky <mschwid2@linux.vnet.ibm.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'master' of ↵Linus Torvalds2009-06-141-10/+231
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild-next * 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/sam/kbuild-next: (53 commits) .gitignore: ignore *.lzma files kbuild: add generic --set-str option to scripts/config kbuild: simplify argument loop in scripts/config kbuild: handle non-existing options in scripts/config kallsyms: generalize text region handling kallsyms: support kernel symbols in Blackfin on-chip memory documentation: make version fix kbuild: fix a compile warning gitignore: Add GNU GLOBAL files to top .gitignore kbuild: fix delay in setlocalversion on readonly source README: fix misleading pointer to the defconf directory vmlinux.lds.h update kernel-doc: cleanup perl script Improve vmlinux.lds.h support for arch specific linker scripts kbuild: fix headers_exports with boolean expression kbuild/headers_check: refine extern check kbuild: fix "Argument list too long" error for "make headers_check", ignore *.patch files Remove bashisms from scripts menu: fix embedded menu presentation ...
| * vmlinux.lds.h updateSam Ravnborg2009-06-141-7/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | Updated after review by Tim Abbott. - Use HEAD_TEXT_SECTION - Drop use of section-names.h and delete file - Introduce EXIT_CALL Deleting section-names.h required a few simple updates of init.h Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Cc: Tim Abbott <tabbott@ksplice.com>
| * Improve vmlinux.lds.h support for arch specific linker scriptsSam Ravnborg2009-06-091-7/+224
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To support alingment of the individual architecture specific linker scripts provide a set of general definitions in vmlinux.lds.h With these definitions applied the diverse linekr scripts can be reduced in line count and their readability are improved - IMO. A sample linker script is included to give the preferred order of the sections for the architectures that do not have any special requirments. These definitions are also a first step towards eventual support for -ffunction-sections. The definitions makes it much easier to do a global renaming of section names - but the main purpose is to clean up the linker scripts. Tim Aboot has provided a lot of inputs to improve the definitions - all faults are mine. Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Cc: Tim Abbott <tabbott@mit.edu>
| * initconst adjustmentsJan Beulich2009-06-091-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | - add .init.rodata to INIT_DATA, and group all initconst flavors together - move strings generated from __setup_param() into .init.rodata - add .*init.rodata to modpost's sets of init sections - make modpost warn about references between meminit and cpuinit as well as memexit and cpuexit sections (as CPU and memory hotplug are independently selectable features) Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
* | Merge branch 'linus' into tracing/coreIngo Molnar2009-05-071-4/+3
|\| | | | | | | | | | | | | Merge reason: tracing/core was on a .30-rc1 base and was missing out on on a handful of tracing fixes present in .30-rc5-almost. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * Remove unused support code for refok sections.Tim Abbott2009-04-271-3/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The old refok sections .text.init.refok .data.init.refok .exit.text.refok have been deprecated since commit 312b1485fb509c9bc32eda28ad29537896658cb8. After the other patches in this patch series nothing is put in these sections, so clean things up by eliminating all the remaining references to them. Signed-off-by: Tim Abbott <tabbott@mit.edu> Acked-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * Add new HEAD_TEXT_SECTION macro.Tim Abbott2009-04-261-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch is preparation for replacing all uses of ".head.text" or ".text.head" in the kernel with macros, so that the section name can later be changed without having to touch a lot of the kernel. Since some linker scripts do more complex things than referencing HEAD_TEXT, we add a HEAD_TEXT_SECTION macro that just contains the actual name. I've defined HEAD_TEXT_SECTION in a new header, include/linux/section-names.h, so that this section name only needs to appear in one place. I anticipate creating similar macro structures for a number of other section names. The long-term goal here is to be able to change the kernel's magic section names to those that are compatible with -ffunction-sections -fdata-sections. This requires renaming all magic sections with names of the form ".text.foo". Signed-off-by: Tim Abbott <tabbott@mit.edu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | tracing/infrastructure: separate event tracer from event supportTom Zanussi2009-04-141-1/+1
|/ | | | | | | | | | | | | | | | | | | Add a new config option, CONFIG_EVENT_TRACING that gets selected when CONFIG_TRACING is selected and adds everything needed by the stuff in trace_export - basically all the event tracing support needed by e.g. bprint, minus the actual events, which are only included if CONFIG_EVENT_TRACER is selected. So CONFIG_EVENT_TRACER can be used to turn on or off the generated events (what I think of as the 'event tracer'), while CONFIG_EVENT_TRACING turns on or off the base event tracing support used by both the event tracer and the other things such as bprint that can't be configured out. Signed-off-by: Tom Zanussi <tzanussi@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: fweisbec@gmail.com LKML-Reference: <1239178441.10295.34.camel@tropicana> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'tracing/core-v2' into tracing-for-linusIngo Molnar2009-04-021-1/+28
|\ | | | | | | | | | | | | | | Conflicts: include/linux/slub_def.h lib/Kconfig.debug mm/slob.c mm/slub.c
| * tracing/syscalls: core infrastructure for syscalls tracing, enhancementsFrederic Weisbecker2009-03-131-1/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: new feature This adds the generic support for syscalls tracing. This is currently exploited through a devoted tracer but other tracing engines can use it. (They just have to play with {start,stop}_ftrace_syscalls() and use the display callbacks unless they want to override them.) The syscalls prototypes definitions are abused here to steal some metadata informations: - syscall name, param types, param names, number of params The syscall addr is not directly saved during this definition because we don't know if its prototype is available in the namespace. But we don't really need it. The arch has just to build a function able to resolve the syscall number to its metadata struct. The current tracer prints the syscall names, parameters names and values (and their types optionally). Currently the value is a raw hex but higher level values diplaying is on my TODO list. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <1236955332-10133-2-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| *-. Merge branches 'tracing/doc', 'tracing/ftrace', 'tracing/printk' and 'linus' ↵Ingo Molnar2009-03-101-1/+1
| |\ \ | | | | | | | | | | | | into tracing/core
| | * | tracing: trace_printk() fix, move format array to data sectionIngo Molnar2009-03-091-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix kernel crash when using trace_printk() trace_printk_fmt section is defined into the readonly section. But we do: trace_printk_fmt = fmt; to fill in that table of format strings - which is not read-only. Under CONFIG_DEBUG_RODATA=y this crashes ... Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | Merge branches 'tracing/doc', 'tracing/ftrace', 'tracing/printk' and ↵Ingo Molnar2009-03-081-4/+51
| |\ \ \ | | |/ / | |/| | | | | | 'tracing/textedit' into tracing/core
| | * | Merge branch 'x86/core' into tracing/texteditIngo Molnar2009-03-061-4/+51
| | |\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: arch/x86/Kconfig block/blktrace.c kernel/irq/handle.c Semantic conflict: kernel/trace/blktrace.c Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | | tracing: add trace_bprintk()Lai Jiangshan2009-03-061-0/+9
| |/ / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: add a generic printk() for tracing, like trace_printk() trace_bprintk() uses the infrastructure to record events on ring_buffer. [ fweisbec@gmail.com: ported to latest -tip, made it work if !CONFIG_MODULES, never free the format strings from modules because we can't keep track of them and conditionnaly create the ftrace format strings section (reported by Steven Rostedt) ] Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-4-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | / tracing: add event trace infrastructureSteven Rostedt2009-02-241-1/+10
| | |/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch creates the event tracing infrastructure of ftrace. It will create the files: /debug/tracing/available_events /debug/tracing/set_event The available_events will list the trace points that have been registered with the event tracer. set_events will allow the user to enable or disable an event hook. example: # echo sched_wakeup > /debug/tracing/set_event Will enable the sched_wakeup event (if it is registered). # echo "!sched_wakeup" >> /debug/tracing/set_event Will disable the sched_wakeup event (and only that event). # echo > /debug/tracing/set_event Will disable all events (notice the '>') # cat /debug/tracing/available_events > /debug/tracing/set_event Will enable all registered event hooks. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
* | | Merge branch 'core/percpu' into percpu-cpumask-x86-for-linus-2Ingo Molnar2009-03-271-4/+51
|\ \ \ | | |/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: arch/parisc/kernel/irq.c arch/x86/include/asm/fixmap_64.h arch/x86/include/asm/setup.h kernel/irq/handle.c Semantic merge: arch/x86/include/asm/fixmap.h Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | linker script: use separate simpler definition for PERCPU()Tejun Heo2009-01-301-5/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: fix linker screwup on x86_32 Recent x86_64 zerobased patches introduced PERCPU_VADDR() to put .data.percpu to a predefined address and re-defined PERCPU() in terms of it. The new macro defined one extra symbol, __per_cpu_load, for LMA of the section so that the init data could be accessed. This new symbol introduced the following problems to x86_32. 1. If __per_cpu_load is defined outside of .data.percpu as an absolute symbol, relocation generation for relocatable kernel fails due to absolute relocation. 2. If __per_cpu_load is put inside .data.percpu with absolute address assignment to work around #1, linker gets confused and under certain configurations ends up relocating the symbol against .data.percpu such that the load address gets added on top of already set load address. As x86_32 doesn't use predefined address for .data.percpu, there's no need for it to care about the possibility of __per_cpu_load being different from __per_cpu_start. This patch defines PERCPU() separately so that __per_cpu_load is defined inside .data.percpu so that everything is ordinary linking-wise. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | Revert "generic, x86: fix __per_cpu_load relocation"Ingo Molnar2009-01-291-4/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit 5a611268b69f05262936dd177205acbce4471358. It is causing occasional boot crashes, caused by certain linker versions (GNU ld version 2.18.50.0.6-2 20080403) messing up: 82dcc000 D __per_cpu_load c16e6000 A __per_cpu_load_abs The __per_cpu_load value is out of whack. Hpa noticed the following detail: * (gdb) p/x -(0xc16e6000-0x82dcc000) * $2 = 0xc16e6000 * I.e. one is the other << 1 The two symbols should be equal. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | generic, x86: fix __per_cpu_load relocationBrian Gerst2009-01-261-3/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes this linker error: WARNING: Absolute relocations present Offset Info Type Sym.Value Sym.Name c0a4e07d 00e78001 R_386_32 c0ab0000 __per_cpu_load Now, __per_cpu_load is a section-relative symbol: c0aa4000 D __per_cpu_load c0aa4000 A __per_cpu_load_abs Signed-off-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | linker script: kill PERCPU_VADDR_PREALLOC()Tejun Heo2009-01-201-37/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: cleanup With .data.percpu.first in place, PERCPU_VADDR_PREALLOC() is no longer necessary. Kill it. Signed-off-by: Tejun Heo <tj@kernel.org>
| * | percpu: refactor percpu.hBrian Gerst2009-01-201-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: cleanup Refactor the DEFINE_PER_CPU_* macros and add .data.percpu.first section. Signed-off-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
| * | linker script: add missing VMLINUX_SYMBOLTejun Heo2009-01-171-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | The newly added PERCPU_*() macros define and use __per_cpu_load but VMLINUX_SYMBOL() was missing from usages causing build failures on archs where linker visible symbol is different from C symbols (e.g. blackfin). Signed-off-by: Tejun Heo <tj@kernel.org>
| * | x86: fold pda into percpu area on SMPTejun Heo2009-01-161-1/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Based on original patch from Christoph Lameter and Mike Travis. ] Currently pdas and percpu areas are allocated separately. %gs points to local pda and percpu area can be reached using pda->data_offset. This patch folds pda into percpu area. Due to strange gcc requirement, pda needs to be at the beginning of the percpu area so that pda->stack_canary is at %gs:40. To achieve this, a new percpu output section macro - PERCPU_VADDR_PREALLOC() - is added and used to reserve pda sized chunk at the start of the percpu area. After this change, for boot cpu, %gs first points to pda in the data.init area and later during setup_per_cpu_areas() gets updated to point to the actual pda. This means that setup_per_cpu_areas() need to reload %gs for CPU0 while clearing pda area for other cpus as cpu0 already has modified it when control reaches setup_per_cpu_areas(). This patch also removes now unnecessary get_local_pda() and its call sites. A lot of this patch is taken from Mike Travis' "x86_64: Fold pda into per cpu area" patch. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | x86: make percpu symbols zerobased on SMPTejun Heo2009-01-161-6/+45
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [ Based on original patch from Christoph Lameter and Mike Travis. ] This patch makes percpu symbols zerobased on x86_64 SMP by adding PERCPU_VADDR() to vmlinux.lds.h which helps setting explicit vaddr on the percpu output section and using it in vmlinux_64.lds.S. A new PHDR is added as existing ones cannot contain sections near address zero. PERCPU_VADDR() also adds a new symbol __per_cpu_load which always points to the vaddr of the loaded percpu data.init region. The following adjustments have been made to accomodate the address change. * code to locate percpu gdt_page in head_64.S is updated to add the load address to the gdt_page offset. * __per_cpu_load is used in places where access to the init data area is necessary. * pda->data_offset is initialized soon after C code is entered as zero value doesn't work anymore. This patch is mostly taken from Mike Travis' "x86_64: Base percpu variables at zero" patch. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* / dynamic debug: combine dprintk and dynamic printkJason Baron2009-03-241-9/+6
|/ | | | | | | | | | | | | | | | | | | | | | | | | 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>
* tracing/function-graph-tracer: add a new .irqentry.text sectionFrederic Weisbecker2008-12-121-0/+10
| | | | | | | | | | | | | Impact: let the function-graph-tracer be aware of the irq entrypoints Add a new .irqentry.text section to store the irq entrypoints functions inside the same section. This way, the tracer will be able to signal an interrupts triggering on output by recognizing these entrypoints. Also, make this section recordable for dynamic tracing. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* trace: profile all if conditionalsSteven Rostedt2008-11-231-1/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: feature to profile if statements This patch adds a branch profiler for all if () statements. The results will be found in: /debugfs/tracing/profile_branch For example: miss hit % Function File Line ------- --------- - -------- ---- ---- 0 1 100 x86_64_start_reservations head64.c 127 0 1 100 copy_bootdata head64.c 69 1 0 0 x86_64_start_kernel head64.c 111 32 0 0 set_intr_gate desc.h 319 1 0 0 reserve_ebda_region head.c 51 1 0 0 reserve_ebda_region head.c 47 0 1 100 reserve_ebda_region head.c 42 0 0 X maxcpus main.c 165 Miss means the branch was not taken. Hit means the branch was taken. The percent is the percentage the branch was taken. This adds a significant amount of overhead and should only be used by those analyzing their system. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* trace: consolidate unlikely and likely profilerSteven Rostedt2008-11-231-6/+3
| | | | | | | | | | | | | | Impact: clean up to make one profiler of like and unlikely tracer The likely and unlikely profiler prints out the file and line numbers of the annotated branches that it is profiling. It shows the number of times it was correct or incorrect in its guess. Having two different files or sections for that matter to tell us if it was a likely or unlikely is pretty pointless. We really only care if it was correct or not. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* tracepoints: add DECLARE_TRACE() and DEFINE_TRACE()Mathieu Desnoyers2008-11-161-0/+1
| | | | | | | | | | | | | | | | | | Impact: API *CHANGE*. Must update all tracepoint users. Add DEFINE_TRACE() to tracepoints to let them declare the tracepoint structure in a single spot for all the kernel. It helps reducing memory consumption, especially when declaring a lot of tracepoints, e.g. for kmalloc tracing. *API CHANGE WARNING*: now, DECLARE_TRACE() must be used in headers for tracepoint declarations rather than DEFINE_TRACE(). This is the sane way to do it. The name previously used was misleading. Updates scheduler instrumentation to follow this API change. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* trace: rename unlikely profiler to branch profilerSteven Rostedt2008-11-121-1/+1
| | | | | | | | | | | | Impact: name change of unlikely tracer and profiler Ingo Molnar suggested changing the config from UNLIKELY_PROFILE to BRANCH_PROFILING. I never did like the "unlikely" name so I went one step farther, and renamed all the unlikely configurations to a "BRANCH" variant. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* tracing: profile likely and unlikely annotationsSteven Rostedt2008-11-121-1/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: new unlikely/likely profiler Andrew Morton recently suggested having an in-kernel way to profile likely and unlikely macros. This patch achieves that goal. When configured, every(*) likely and unlikely macro gets a counter attached to it. When the condition is hit, the hit and misses of that condition are recorded. These numbers can later be retrieved by: /debugfs/tracing/profile_likely - All likely markers /debugfs/tracing/profile_unlikely - All unlikely markers. # cat /debug/tracing/profile_unlikely | head correct incorrect % Function File Line ------- --------- - -------- ---- ---- 2167 0 0 do_arch_prctl process_64.c 832 0 0 0 do_arch_prctl process_64.c 804 2670 0 0 IS_ERR err.h 34 71230 5693 7 __switch_to process_64.c 673 76919 0 0 __switch_to process_64.c 639 43184 33743 43 __switch_to process_64.c 624 12740 64181 83 __switch_to process_64.c 594 12740 64174 83 __switch_to process_64.c 590 # cat /debug/tracing/profile_unlikely | \ awk '{ if ($3 > 25) print $0; }' |head -20 44963 35259 43 __switch_to process_64.c 624 12762 67454 84 __switch_to process_64.c 594 12762 67447 84 __switch_to process_64.c 590 1478 595 28 syscall_get_error syscall.h 51 0 2821 100 syscall_trace_leave ptrace.c 1567 0 1 100 native_smp_prepare_cpus smpboot.c 1237 86338 265881 75 calc_delta_fair sched_fair.c 408 210410 108540 34 calc_delta_mine sched.c 1267 0 54550 100 sched_info_queued sched_stats.h 222 51899 66435 56 pick_next_task_fair sched_fair.c 1422 6 10 62 yield_task_fair sched_fair.c 982 7325 2692 26 rt_policy sched.c 144 0 1270 100 pre_schedule_rt sched_rt.c 1261 1268 48073 97 pick_next_task_rt sched_rt.c 884 0 45181 100 sched_info_dequeued sched_stats.h 177 0 15 100 sched_move_task sched.c 8700 0 15 100 sched_move_task sched.c 8690 53167 33217 38 schedule sched.c 4457 0 80208 100 sched_info_switch sched_stats.h 270 30585 49631 61 context_switch sched.c 2619 # cat /debug/tracing/profile_likely | awk '{ if ($3 > 25) print $0; }' 39900 36577 47 pick_next_task sched.c 4397 20824 15233 42 switch_mm mmu_context_64.h 18 0 7 100 __cancel_work_timer workqueue.c 560 617 66484 99 clocksource_adjust timekeeping.c 456 0 346340 100 audit_syscall_exit auditsc.c 1570 38 347350 99 audit_get_context auditsc.c 732 0 345244 100 audit_syscall_entry auditsc.c 1541 38 1017 96 audit_free auditsc.c 1446 0 1090 100 audit_alloc auditsc.c 862 2618 1090 29 audit_alloc auditsc.c 858 0 6 100 move_masked_irq migration.c 9 1 198 99 probe_sched_wakeup trace_sched_switch.c 58 2 2 50 probe_wakeup trace_sched_wakeup.c 227 0 2 100 probe_wakeup_sched_switch trace_sched_wakeup.c 144 4514 2090 31 __grab_cache_page filemap.c 2149 12882 228786 94 mapping_unevictable pagemap.h 50 4 11 73 __flush_cpu_slab slub.c 1466 627757 330451 34 slab_free slub.c 1731 2959 61245 95 dentry_lru_del_init dcache.c 153 946 1217 56 load_elf_binary binfmt_elf.c 904 102 82 44 disk_put_part genhd.h 206 1 1 50 dst_gc_task dst.c 82 0 19 100 tcp_mss_split_point tcp_output.c 1126 As you can see by the above, there's a bit of work to do in rethinking the use of some unlikelys and likelys. Note: the unlikely case had 71 hits that were more than 25%. Note: After submitting my first version of this patch, Andrew Morton showed me a version written by Daniel Walker, where I picked up the following ideas from: 1) Using __builtin_constant_p to avoid profiling fixed values. 2) Using __FILE__ instead of instruction pointers. 3) Using the preprocessor to stop all profiling of likely annotations from vsyscall_64.c. Thanks to Andrew Morton, Arjan van de Ven, Theodore Tso and Ingo Molnar for their feed back on this patch. (*) Not ever unlikely is recorded, those that are used by vsyscalls (a few of them) had to have profiling disabled. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Theodore Tso <tytso@mit.edu> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'tracing-v28-for-linus' of ↵Linus Torvalds2008-10-201-1/+13
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'tracing-v28-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (131 commits) tracing/fastboot: improve help text tracing/stacktrace: improve help text tracing/fastboot: fix initcalls disposition in bootgraph.pl tracing/fastboot: fix bootgraph.pl initcall name regexp tracing/fastboot: fix issues and improve output of bootgraph.pl tracepoints: synchronize unregister static inline tracepoints: tracepoint_synchronize_unregister() ftrace: make ftrace_test_p6nop disassembler-friendly markers: fix synchronize marker unregister static inline tracing/fastboot: add better resolution to initcall debug/tracing trace: add build-time check to avoid overrunning hex buffer ftrace: fix hex output mode of ftrace tracing/fastboot: fix initcalls disposition in bootgraph.pl tracing/fastboot: fix printk format typo in boot tracer ftrace: return an error when setting a nonexistent tracer ftrace: make some tracers reentrant ring-buffer: make reentrant ring-buffer: move page indexes into page headers tracing/fastboot: only trace non-module initcalls ftrace: move pc counter in irqtrace ... Manually fix conflicts: - init/main.c: initcall tracing - kernel/module.c: verbose level vs tracepoints - scripts/bootgraph.pl: fallout from cherry-picking commits.
| * ftrace: create __mcount_loc sectionSteven Rostedt2008-10-141-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch creates a section in the kernel called "__mcount_loc". This will hold a list of pointers to the mcount relocation for each call site of mcount. For example: objdump -dr init/main.o [...] Disassembly of section .text: 0000000000000000 <do_one_initcall>: 0: 55 push %rbp [...] 000000000000017b <init_post>: 17b: 55 push %rbp 17c: 48 89 e5 mov %rsp,%rbp 17f: 53 push %rbx 180: 48 83 ec 08 sub $0x8,%rsp 184: e8 00 00 00 00 callq 189 <init_post+0xe> 185: R_X86_64_PC32 mcount+0xfffffffffffffffc [...] We will add a section to point to each function call. .section __mcount_loc,"a",@progbits [...] .quad .text + 0x185 [...] The offset to of the mcount call site in init_post is an offset from the start of the section, and not the start of the function init_post. The mcount relocation is at the call site 0x185 from the start of the .text section. .text + 0x185 == init_post + 0xa We need a way to add this __mcount_loc section in a way that we do not lose the relocations after final link. The .text section here will be attached to all other .text sections after final link and the offsets will be meaningless. We need to keep track of where these .text sections are. To do this, we use the start of the first function in the section. do_one_initcall. We can make a tmp.s file with this function as a reference to the start of the .text section. .section __mcount_loc,"a",@progbits [...] .quad do_one_initcall + 0x185 [...] Then we can compile the tmp.s into a tmp.o gcc -c tmp.s -o tmp.o And link it into back into main.o. ld -r main.o tmp.o -o tmp_main.o mv tmp_main.o main.o But we have a problem. What happens if the first function in a section is not exported, and is a static function. The linker will not let the tmp.o use it. This case exists in main.o as well. Disassembly of section .init.text: 0000000000000000 <set_reset_devices>: 0: 55 push %rbp 1: 48 89 e5 mov %rsp,%rbp 4: e8 00 00 00 00 callq 9 <set_reset_devices+0x9> 5: R_X86_64_PC32 mcount+0xfffffffffffffffc The first function in .init.text is a static function. 00000000000000a8 t __setup_set_reset_devices 000000000000105f t __setup_str_set_reset_devices 0000000000000000 t set_reset_devices The lowercase 't' means that set_reset_devices is local and is not exported. If we simply try to link the tmp.o with the set_reset_devices we end up with two symbols: one local and one global. .section __mcount_loc,"a",@progbits .quad set_reset_devices + 0x10 00000000000000a8 t __setup_set_reset_devices 000000000000105f t __setup_str_set_reset_devices 0000000000000000 t set_reset_devices U set_reset_devices We still have an undefined reference to set_reset_devices, and if we try to compile the kernel, we will end up with an undefined reference to set_reset_devices, or even worst, it could be exported someplace else, and then we will have a reference to the wrong location. To handle this case, we make an intermediate step using objcopy. We convert set_reset_devices into a global exported symbol before linking it with tmp.o and set it back afterwards. 00000000000000a8 t __setup_set_reset_devices 000000000000105f t __setup_str_set_reset_devices 0000000000000000 T set_reset_devices 00000000000000a8 t __setup_set_reset_devices 000000000000105f t __setup_str_set_reset_devices 0000000000000000 T set_reset_devices 00000000000000a8 t __setup_set_reset_devices 000000000000105f t __setup_str_set_reset_devices 0000000000000000 t set_reset_devices Now we have a section in main.o called __mcount_loc that we can place somewhere in the kernel using vmlinux.ld.S and access it to convert all these locations that call mcount into nops before starting SMP and thus, eliminating the need to do this with kstop_machine. Note, A well documented perl script (scripts/recordmcount.pl) is used to do all this in one location. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * tracing: Kernel TracepointsMathieu Desnoyers2008-10-141-1/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Implementation of kernel tracepoints. Inspired from the Linux Kernel Markers. Allows complete typing verification by declaring both tracing statement inline functions and probe registration/unregistration static inline functions within the same macro "DEFINE_TRACE". No format string is required. See the tracepoint Documentation and Samples patches for usage examples. Taken from the documentation patch : "A tracepoint placed in code provides a hook to call a function (probe) that you can provide at runtime. A tracepoint can be "on" (a probe is connected to it) or "off" (no probe is attached). When a tracepoint is "off" it has no effect, except for adding a tiny time penalty (checking a condition for a branch) and space penalty (adding a few bytes for the function call at the end of the instrumented function and adds a data structure in a separate section). When a tracepoint is "on", the function you provide is called each time the tracepoint is executed, in the execution context of the caller. When the function provided ends its execution, it returns to the caller (continuing from the tracepoint site). You can put tracepoints at important locations in the code. They are lightweight hooks that can pass an arbitrary number of parameters, which prototypes are described in a tracepoint declaration placed in a header file." Addition and removal of tracepoints is synchronized by RCU using the scheduler (and preempt_disable) as guarantees to find a quiescent state (this is really RCU "classic"). The update side uses rcu_barrier_sched() with call_rcu_sched() and the read/execute side uses "preempt_disable()/preempt_enable()". We make sure the previous array containing probes, which has been scheduled for deletion by the rcu callback, is indeed freed before we proceed to the next update. It therefore limits the rate of modification of a single tracepoint to one update per RCU period. The objective here is to permit fast batch add/removal of probes on _different_ tracepoints. Changelog : - Use #name ":" #proto as string to identify the tracepoint in the tracepoint table. This will make sure not type mismatch happens due to connexion of a probe with the wrong type to a tracepoint declared with the same name in a different header. - Add tracepoint_entry_free_old. - Change __TO_TRACE to get rid of the 'i' iterator. Masami Hiramatsu <mhiramat@redhat.com> : Tested on x86-64. Performance impact of a tracepoint : same as markers, except that it adds about 70 bytes of instructions in an unlikely branch of each instrumented function (the for loop, the stack setup and the function call). It currently adds a memory read, a test and a conditional branch at the instrumentation site (in the hot path). Immediate values will eventually change this into a load immediate, test and branch, which removes the memory read which will make the i-cache impact smaller (changing the memory read for a load immediate removes 3-4 bytes per site on x86_32 (depending on mov prefixes), or 7-8 bytes on x86_64, it also saves the d-cache hit). About the performance impact of tracepoints (which is comparable to markers), even without immediate values optimizations, tests done by Hideo Aoki on ia64 show no regression. His test case was using hackbench on a kernel where scheduler instrumentation (about 5 events in code scheduler code) was added. Quoting Hideo Aoki about Markers : I evaluated overhead of kernel marker using linux-2.6-sched-fixes git tree, which includes several markers for LTTng, using an ia64 server. While the immediate trace mark feature isn't implemented on ia64, there is no major performance regression. So, I think that we don't have any issues to propose merging marker point patches into Linus's tree from the viewpoint of performance impact. I prepared two kernels to evaluate. The first one was compiled without CONFIG_MARKERS. The second one was enabled CONFIG_MARKERS. I downloaded the original hackbench from the following URL: http://devresources.linux-foundation.org/craiger/hackbench/src/hackbench.c I ran hackbench 5 times in each condition and calculated the average and difference between the kernels. The parameter of hackbench: every 50 from 50 to 800 The number of CPUs of the server: 2, 4, and 8 Below is the results. As you can see, major performance regression wasn't found in any case. Even if number of processes increases, differences between marker-enabled kernel and marker- disabled kernel doesn't increase. Moreover, if number of CPUs increases, the differences doesn't increase either. Curiously, marker-enabled kernel is better than marker-disabled kernel in more than half cases, although I guess it comes from the difference of memory access pattern. * 2 CPUs Number of | without | with | diff | diff | processes | Marker [Sec] | Marker [Sec] | [Sec] | [%] | -------------------------------------------------------------- 50 | 4.811 | 4.872 | +0.061 | +1.27 | 100 | 9.854 | 10.309 | +0.454 | +4.61 | 150 | 15.602 | 15.040 | -0.562 | -3.6 | 200 | 20.489 | 20.380 | -0.109 | -0.53 | 250 | 25.798 | 25.652 | -0.146 | -0.56 | 300 | 31.260 | 30.797 | -0.463 | -1.48 | 350 | 36.121 | 35.770 | -0.351 | -0.97 | 400 | 42.288 | 42.102 | -0.186 | -0.44 | 450 | 47.778 | 47.253 | -0.526 | -1.1 | 500 | 51.953 | 52.278 | +0.325 | +0.63 | 550 | 58.401 | 57.700 | -0.701 | -1.2 | 600 | 63.334 | 63.222 | -0.112 | -0.18 | 650 | 68.816 | 68.511 | -0.306 | -0.44 | 700 | 74.667 | 74.088 | -0.579 | -0.78 | 750 | 78.612 | 79.582 | +0.970 | +1.23 | 800 | 85.431 | 85.263 | -0.168 | -0.2 | -------------------------------------------------------------- * 4 CPUs Number of | without | with | diff | diff | processes | Marker [Sec] | Marker [Sec] | [Sec] | [%] | -------------------------------------------------------------- 50 | 2.586 | 2.584 | -0.003 | -0.1 | 100 | 5.254 | 5.283 | +0.030 | +0.56 | 150 | 8.012 | 8.074 | +0.061 | +0.76 | 200 | 11.172 | 11.000 | -0.172 | -1.54 | 250 | 13.917 | 14.036 | +0.119 | +0.86 | 300 | 16.905 | 16.543 | -0.362 | -2.14 | 350 | 19.901 | 20.036 | +0.135 | +0.68 | 400 | 22.908 | 23.094 | +0.186 | +0.81 | 450 | 26.273 | 26.101 | -0.172 | -0.66 | 500 | 29.554 | 29.092 | -0.461 | -1.56 | 550 | 32.377 | 32.274 | -0.103 | -0.32 | 600 | 35.855 | 35.322 | -0.533 | -1.49 | 650 | 39.192 | 38.388 | -0.804 | -2.05 | 700 | 41.744 | 41.719 | -0.025 | -0.06 | 750 | 45.016 | 44.496 | -0.520 | -1.16 | 800 | 48.212 | 47.603 | -0.609 | -1.26 | -------------------------------------------------------------- * 8 CPUs Number of | without | with | diff | diff | processes | Marker [Sec] | Marker [Sec] | [Sec] | [%] | -------------------------------------------------------------- 50 | 2.094 | 2.072 | -0.022 | -1.07 | 100 | 4.162 | 4.273 | +0.111 | +2.66 | 150 | 6.485 | 6.540 | +0.055 | +0.84 | 200 | 8.556 | 8.478 | -0.078 | -0.91 | 250 | 10.458 | 10.258 | -0.200 | -1.91 | 300 | 12.425 | 12.750 | +0.325 | +2.62 | 350 | 14.807 | 14.839 | +0.032 | +0.22 | 400 | 16.801 | 16.959 | +0.158 | +0.94 | 450 | 19.478 | 19.009 | -0.470 | -2.41 | 500 | 21.296 | 21.504 | +0.208 | +0.98 | 550 | 23.842 | 23.979 | +0.137 | +0.57 | 600 | 26.309 | 26.111 | -0.198 | -0.75 | 650 | 28.705 | 28.446 | -0.259 | -0.9 | 700 | 31.233 | 31.394 | +0.161 | +0.52 | 750 | 34.064 | 33.720 | -0.344 | -1.01 | 800 | 36.320 | 36.114 | -0.206 | -0.57 | -------------------------------------------------------------- Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Acked-by: Masami Hiramatsu <mhiramat@redhat.com> Acked-by: 'Peter Zijlstra' <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | driver core: basic infrastructure for per-module dynamic debug messagesJason Baron2008-10-161-1/+9
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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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