linux.git/arch/x86/include/asm/stacktrace.h, branch v2.6.37

perf: Drop the skip argument from perf_arch_fetch_regs_caller

2010-06-08T21:31:27+00:00

Drop this argument now that we always want to rewind only to the
state of the first caller.
It means frame pointers are not necessary anymore to reliably get
the source of an event. But this also means we need this helper
to be a macro now, as an inline function is not an option since
we need to know when to provide a default implentation.

Signed-off-by: Frederic Weisbecker 
Signed-off-by: Paul Mackerras 
Cc: David Miller 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Arnaldo Carvalho de Melo

x86: Unify dumpstack.h and stacktrace.h

2010-06-08T21:29:52+00:00

arch/x86/include/asm/stacktrace.h and arch/x86/kernel/dumpstack.h
declare headers of objects that deal with the same topic.
Actually most of the files that include stacktrace.h also include
dumpstack.h

Although dumpstack.h seems more reserved for internals of stack
traces, those are quite often needed to define specialized stack
trace operations. And perf event arch headers are going to need
access to such low level operations anyway. So don't continue to
bother with dumpstack.h as it's not anymore about isolated deep
internals.

v2: fix struct stack_frame definition conflict in sysprof

Signed-off-by: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: H. Peter Anvin 
Cc: Thomas Gleixner 
Cc: Soeren Sandmann

perf: Drop useless check for ignored frame

2010-01-13T09:09:08+00:00

The check that ignores the debug and nmi stack frames is useless
now that we have a frame pointer that makes us start at the
right place. We don't anymore have to deal with these.

Signed-off-by: Frederic Weisbecker 
Cc: Peter Zijlstra 
Cc: Arnaldo Carvalho de Melo 
Cc: Paul Mackerras 
LKML-Reference: <1262235183-5320-2-git-send-regression-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar

perf events, x86/stacktrace: Fix performance/softlockup by providing a special frame pointer-only stack walker

2009-12-17T09:42:52+00:00

It's just wasteful for stacktrace users like perf to walk
through every entries on the stack whereas these only accept
reliable ones, ie: that the frame pointer validates.

Since perf requires pure reliable stacktraces, it needs a stack
walker based on frame pointers-only to optimize the stacktrace
processing.

This might solve some near-lockup scenarios that can be triggered
by call-graph tracing timer events.

Signed-off-by: Frederic Weisbecker 
Cc: Peter Zijlstra 
Cc: Arnaldo Carvalho de Melo 
Cc: Paul Mackerras 
LKML-Reference: <1261024834-5336-2-git-send-regression-fweisbec@gmail.com>
[ v2: fix for modular builds and small detail tidyup ]
Signed-off-by: Ingo Molnar

perf events, x86/stacktrace: Make stack walking optional

2009-12-17T08:56:19+00:00

The current print_context_stack helper that does the stack
walking job is good for usual stacktraces as it walks through
all the stack and reports even addresses that look unreliable,
which is nice when we don't have frame pointers for example.

But we have users like perf that only require reliable
stacktraces, and those may want a more adapted stack walker, so
lets make this function a callback in stacktrace_ops that users
can tune for their needs.

Signed-off-by: Frederic Weisbecker 
Cc: Peter Zijlstra 
Cc: Arnaldo Carvalho de Melo 
Cc: Paul Mackerras 
LKML-Reference: <1261024834-5336-1-git-send-regression-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar

perf_counter: Ignore the nmi call frames in the x86-64 backtraces

2009-07-01T20:37:23+00:00

About every callchains recorded with perf record are filled up
including the internal perfcounter nmi frame:

 perf_callchain
 perf_counter_overflow
 intel_pmu_handle_irq
 perf_counter_nmi_handler
 notifier_call_chain
 atomic_notifier_call_chain
 notify_die
 do_nmi
 nmi

We want ignore this frame as it's not interesting for
instrumentation. To solve this, we simply ignore every frames
from nmi context.

New example of "perf report -s sym -c" after this patch:

9.59%  [k] search_by_key
             4.88%
                search_by_key
                reiserfs_read_locked_inode
                reiserfs_iget
                reiserfs_lookup
                do_lookup
                __link_path_walk
                path_walk
                do_path_lookup
                user_path_at
                vfs_fstatat
                vfs_lstat
                sys_newlstat
                system_call_fastpath
                __lxstat
                0x406fb1

             3.19%
                search_by_key
                search_by_entry_key
                reiserfs_find_entry
                reiserfs_lookup
                do_lookup
                __link_path_walk
                path_walk
                do_path_lookup
                user_path_at
                vfs_fstatat
                vfs_lstat
                sys_newlstat
                system_call_fastpath
                __lxstat
                0x406fb1
[...]

For now this patch only solves the problem in x86-64.

Signed-off-by: Frederic Weisbecker 
Cc: Peter Zijlstra 
Cc: Mike Galbraith 
Cc: Paul Mackerras 
Cc: Anton Blanchard 
Cc: Arnaldo Carvalho de Melo 
LKML-Reference: <1246474930-6088-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar

x86: Fix ASM_X86__ header guards

2008-10-23T05:55:23+00:00

Change header guards named "ASM_X86__*" to "_ASM_X86_*" since:

a. the double underscore is ugly and pointless.
b. no leading underscore violates namespace constraints.

Signed-off-by: H. Peter Anvin

x86, um: ... and asm-x86 move

2008-10-23T05:55:20+00:00

Signed-off-by: Al Viro 
Signed-off-by: H. Peter Anvin