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* branch tracer, intel-iommu: fix build with CONFIG_BRANCH_TRACER=yLinus Torvalds2009-04-07
| | | | | | | Fix the branch tracer barfing on comma statements within if () statements. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* branch tracer: Fix for enabling branch profiling makes sparse unusableBart Van Assche2009-04-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | One of the changes between kernels 2.6.28 and 2.6.29 is that a branch profiler has been added for if() statements. Unfortunately this patch makes the sparse output unusable with CONFIG_TRACE_BRANCH_PROFILING=y: when branch profiling is enabled, sparse prints so much false positives that the real issues are no longer visible. This behavior can be reproduced as follows: * enable CONFIG_TRACE_BRANCH_PROFILING, e.g. by running make allyesconfig or make allmodconfig. * run make C=2 Result: a huge number of the following sparse warnings. ... include/linux/cpumask.h:547:2: warning: symbol '______r' shadows an earlier one include/linux/cpumask.h:547:2: originally declared here ... The patch below fixes this by disabling branch profiling while analyzing the kernel code with sparse. See also: * http://lkml.org/lkml/2008/11/21/18 * http://bugzilla.kernel.org/show_bug.cgi?id=12925 Signed-off-by: Bart Van Assche <bart.vanassche@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Steven Rostedt <srostedt@redhat.com> LKML-Reference: <200904051620.02311.bart.vanassche@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* tracing: optimization of branch tracerWitold Baryluk2009-03-17
| | | | | | | | | | | Impact: better performance for if branch tracer Use an array to count the hit and misses of a conditional instead of using another conditional. This cuts down on saturation of branch predictions and increases performance of modern pipelined architectures. Signed-off-by: Witold Baryluk <baryluk@smp.if.uj.edu.pl> Signed-off-by: Steven Rostedt <srostedt@redhat.com>
* Sanitize gcc version header includesLinus Torvalds2009-01-02
| | | | | | | | | | | | | | | - include the gcc version-dependent header files from the generic gcc header file, rather than the other way around (iow: don't make the non-gcc header file have to know about gcc versions) - don't include compiler-gcc4.h for gcc 5 (for whenever it gets released). That's just confusing and made us do odd things in the gcc4 header file (testing that we really had version 4!) - generate the name from the __GNUC__ version directly, rather than having a mess of #if conditionals. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* trace: profile all if conditionalsSteven Rostedt2008-11-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 Rostedt2008-11-23
| | | | | | | | | | | | | | 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>
* trace: remove extra assign in branch checkSteven Rostedt2008-11-23
| | | | | | | | | | Impact: clean up of branch check The unlikely/likely profiler does an extra assign of the f.line. This is not needed since it is already calculated at compile time. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* trace: rename unlikely profiler to branch profilerSteven Rostedt2008-11-12
| | | | | | | | | | | | 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: branch tracer, fix vdso crashIngo Molnar2008-11-12
| | | | | | | | | | | | | | | Impact: fix bootup crash the branch tracer missed arch/x86/vdso/vclock_gettime.c from disabling tracing, which caused such bootup crashes: [ 201.840097] init[1]: segfault at 7fffed3fe7c0 ip 00007fffed3fea2e sp 000077 also clean up the ugly ifdefs in arch/x86/kernel/vsyscall_64.c by creating DISABLE_UNLIKELY_PROFILE facility for code to turn off instrumentation on a per file basis. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* tracing: profile likely and unlikely annotationsSteven Rostedt2008-11-12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* ftrace: move notrace to compiler.hSteven Rostedt2008-10-14
| | | | | | | | The notrace define belongs in compiler.h so that it can be used in init.h Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* rcu: remove redundant ACCESS_ONCE definition from rcupreempt.cPaul E. McKenney2008-08-18
| | | | | | | | | Remove the redundant definition of ACCESS_ONCE() from rcupreempt.c in favor of the one in compiler.h. Also merge the comment header from rcupreempt.c's definition into that in compiler.h. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Move ACCESS_ONCE() to <linux/compiler.h>Linus Torvalds2008-05-10
| | | | | | | | | It actually makes much more sense there, and we do tend to need it for non-RCU usage too. Moving it to <linux/compiler.h> will allow some other cases that have open-coded the same logic to use the same helper function that RCU has used. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* add noinline_for_stackAndrew Morton2008-03-04
| | | | | | | | | | People are adding `noinline' in various places to prevent excess stack consumption due to gcc inlining. But once this is done, it is quite unobvious why the `noinline' is present in the code. We can comment each and every site, or we can use noinline_for_stack. Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* remove __attribute_used__Adrian Bunk2008-01-28
| | | | | | | | | Remove the deprecated __attribute_used__. [Introduce __section in a few places to silence checkpatch /sam] Signed-off-by: Adrian Bunk <bunk@kernel.org> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
* compiler.h: introduce __section()Sam Ravnborg2008-01-28
| | | | | | | Add a new helper: __section() that makes a section definition much shorter and more readable. Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
* Permit silencing of __deprecated warnings.Jeff Garzik2007-10-25
| | | | | | | | | | | | | | | | | | The __deprecated marker is quite useful in highlighting the remnants of old APIs that want removing. However, it is quite normal for one or more years to pass, before the (usually ancient, bitrotten) code in question is either updated or deleted. Thus, like __must_check, add a Kconfig option that permits the silencing of this compiler warning. This change mimics the ifdef-ery and Kconfig defaults of MUST_CHECK as closely as possible. Signed-off-by: Jeff Garzik <jgarzik@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Replace __attribute_pure__ with __pureRalf Baechle2007-10-18
| | | | | | | | | | | | | | | To be consistent with the use of attributes in the rest of the kernel replace all use of __attribute_pure__ with __pure and delete the definition of __attribute_pure__. Signed-off-by: Ralf Baechle <ralf@linux-mips.org> Cc: Russell King <rmk@arm.linux.org.uk> Acked-by: Mauro Carvalho Chehab <mchehab@infradead.org> Cc: Bryan Wu <bryan.wu@analog.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* make __chk_{user,io}_ptr() accept pointers to volatileAl Viro2007-07-26
| | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* x86: Support __attribute__((__cold__)) in gcc 4.3Andi Kleen2007-07-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | gcc 4.3 supports a new __attribute__((__cold__)) to mark functions cold. Any path directly leading to a call of this function will be unlikely. And gcc will try to generate smaller code for the function itself. Please use with care. The code generation advantage isn't large and in most cases it is not worth uglifying code with this. This patch marks some common error functions like panic(), printk() as cold. This will longer term make many unlikely()s unnecessary, although we can keep them for now for older compilers. BUG is not marked cold because there is currently no way to tell gcc to mark a inline function told. Also all __init and __exit functions are marked cold. With a non -Os build this will tell the compiler to generate slightly smaller code for them. I think it currently only uses less alignments for labels, but that might change in the future. One disadvantage over *likely() is that they cannot be easily instrumented to verify them. Another drawback is that only the latest gcc 4.3 snapshots support this. Unfortunately we cannot detect this using the preprocessor. This means older snapshots will fail now. I don't think that's a problem because they are unreleased compilers that nobody should be using. gcc also has a __hot__ attribute, but I don't see any sense in using this in the kernel right now. But someday I hope gcc will be able to use more aggressive optimizing for hot functions even in -Os, if that happens it should be added. Includes compile fix from Thomas Gleixner. Cc: Jan Hubicka <jh@suse.cz> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* x86_64: Support gcc 5 properlyAndi Kleen2007-05-21
| | | | | | | The ifdef tests were broken. Assume it acts like gcc 4 Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* compiler: introduce __used and __maybe_unusedDavid Rientjes2007-05-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | __used is defined to be __attribute__((unused)) for all pre-3.3 gcc compilers to suppress warnings for unused functions because perhaps they are referenced only in inline assembly. It is defined to be __attribute__((used)) for gcc 3.3 and later so that the code is still emitted for such functions. __maybe_unused is defined to be __attribute__((unused)) for both function and variable use if it could possibly be unreferenced due to the evaluation of preprocessor macros. Function prototypes shall be marked with __maybe_unused if the actual definition of the function is dependant on preprocessor macros. No update to compiler-intel.h is necessary because ICC supports both __attribute__((used)) and __attribute__((unused)) as specified by the gcc manual. __attribute_used__ is deprecated and will be removed once all current code is converted to using __used. Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Adrian Bunk <bunk@stusta.de> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] Add const to pointer qualifiers for __chk_user_ptr and __chk_io_ptr.Russ Cox2007-03-26
| | | | | | | | | | | | | | | Change prototypes for __chk_user_ptr and __chk_io_ptr to take const void* instead of void*, so that code can pass "const void *" to them. (Right now sparse does not warn about passing const void* to void* functions, but that is a separate bug that I believe Josh is working on, and once sparse does check this, the changed prototypes will be necessary.) Signed-off-by: Russ Cox <rsc@swtch.com> Signed-off-by: Josh Triplett <josh@freedesktop.org> Acked-by: Christopher Li <sparse@chrisli.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* include/linux/compiler.h: reject gcc 3 < gcc 3.2Alistair John Strachan2006-12-12
| | | | | | | | The kernel doesn't compile with GCC <3.2, do not allow it to succeed if GCC 3.0.x or 3.1.x are used. Signed-off-by: Alistair John Strachan <s0348365@sms.ed.ac.uk> Signed-off-by: Adrian Bunk <bunk@stusta.de>
* [PATCH] Pass sparse the lock expression given to lock annotationsJosh Triplett2006-10-01
| | | | | | | | | | | | | The lock annotation macros __acquires, __releases, __acquire, and __release all currently throw away the lock expression passed as an argument. Now that sparse can parse __context__ and __attribute__((context)) with a context expression, pass the lock expression down to sparse as the context expression. This requires a version of sparse from GIT commit 37475a6c1c3e66219e68d912d5eb833f4098fd72 or later. Signed-off-by: Josh Triplett <josh@freedesktop.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Pass a lock expression to __cond_lock, like __acquire and __releaseJosh Triplett2006-09-29
| | | | | | | | | | | Currently, __acquire and __release take a lock expression, but __cond_lock takes only a condition, not the lock acquired if the expression evaluates to true. Change __cond_lock to accept a lock expression, and change all the callers to pass in a lock expression. Signed-off-by: Josh Triplett <josh@freedesktop.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* add CONFIG_ENABLE_MUST_CHECKAndrew Morton2006-09-26
| | | | | | | | | Those 1500 warnings can be a bit of a pain. Add a config option to shut them up. Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* Restore __attribute_const__ to user-visibility in linux/compiler.h...for nowDavid Woodhouse2006-05-03
| | | | Signed-off-by: David Woodhouse <dwmw2@infradead.org>
* Guard some of linux/compiler.h with #ifdef __KERNEL__David Woodhouse2006-05-02
| | | | Signed-off-by: David Woodhouse <dwmw2@infradead.org>
* [PATCH] Abandon gcc-2.95.xAndrew Morton2006-01-08
| | | | | | | | | | | | | | There's one scsi driver which doesn't compile due to weird __VA_ARGS__ tricks and the rather useful scsi/sd.c is currently getting an ICE. None of the new SAS code compiles, due to extensive use of anonymous unions. The V4L guys are very good at exploiting the gcc-2.95.x macro expansion bug (_why_ does each driver need to implement its own debug macros?) and various people keep on sneaking in anonymous unions, which are rather nice. Plus anonymous unions are rather useful. Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Add deprecated_for_modulesPaul E. McKenney2005-05-01
| | | | | | | | | Add a deprecated_for_modules macro that allows symbols to be deprecated only when used by modules, as suggested by Andrew Morton some months back. Signed-off-by: Paul E. McKenney <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Linux-2.6.12-rc2v2.6.12-rc2Linus Torvalds2005-04-16
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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