Commit 5cc718b9dad682329a60e73547c6e708faa5bbe4
Committed by
Ingo Molnar
Ingo Molnar
1 parent
8ea7f54410
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kprobes: Hide CONFIG_OPTPROBES and set if arch supports optimized kprobes
Hide CONFIG_OPTPROBES and set if the arch supports optimized kprobes (IOW, HAVE_OPTPROBES=y), since this option doesn't change the major behavior of kprobes, and workarounds for minor changes are documented. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: systemtap <systemtap@sources.redhat.com> Cc: DLE <dle-develop@lists.sourceforge.net> Cc: Dieter Ries <mail@dieterries.net> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <20100315170054.31593.3153.stgit@localhost6.localdomain6> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Showing 2 changed files with 4 additions and 15 deletions Side-by-side Diff
Documentation/kprobes.txt
| ... | ... | @@ -165,8 +165,8 @@ |
| 165 | 165 | |
| 166 | 166 | 1.4 How Does Jump Optimization Work? |
| 167 | 167 | |
| 168 | -If you configured your kernel with CONFIG_OPTPROBES=y (currently | |
| 169 | -this option is supported on x86/x86-64, non-preemptive kernel) and | |
| 168 | +If your kernel is built with CONFIG_OPTPROBES=y (currently this flag | |
| 169 | +is automatically set 'y' on x86/x86-64, non-preemptive kernel) and | |
| 170 | 170 | the "debug.kprobes_optimization" kernel parameter is set to 1 (see |
| 171 | 171 | sysctl(8)), Kprobes tries to reduce probe-hit overhead by using a jump |
| 172 | 172 | instruction instead of a breakpoint instruction at each probepoint. |
| ... | ... | @@ -271,8 +271,6 @@ |
| 271 | 271 | using one of the following techniques: |
| 272 | 272 | - Specify an empty function for the kprobe's post_handler or break_handler. |
| 273 | 273 | or |
| 274 | -- Config CONFIG_OPTPROBES=n. | |
| 275 | - or | |
| 276 | 274 | - Execute 'sysctl -w debug.kprobes_optimization=n' |
| 277 | 275 | |
| 278 | 276 | 2. Architectures Supported |
| ... | ... | @@ -306,10 +304,6 @@ |
| 306 | 304 | it useful to "Compile the kernel with debug info" (CONFIG_DEBUG_INFO), |
| 307 | 305 | so you can use "objdump -d -l vmlinux" to see the source-to-object |
| 308 | 306 | code mapping. |
| 309 | - | |
| 310 | -If you want to reduce probing overhead, set "Kprobes jump optimization | |
| 311 | -support" (CONFIG_OPTPROBES) to "y". You can find this option under the | |
| 312 | -"Kprobes" line. | |
| 313 | 307 | |
| 314 | 308 | 4. API Reference |
| 315 | 309 |
arch/Kconfig
| ... | ... | @@ -42,15 +42,10 @@ |
| 42 | 42 | If in doubt, say "N". |
| 43 | 43 | |
| 44 | 44 | config OPTPROBES |
| 45 | - bool "Kprobes jump optimization support (EXPERIMENTAL)" | |
| 46 | - default y | |
| 47 | - depends on KPROBES | |
| 45 | + def_bool y | |
| 46 | + depends on KPROBES && HAVE_OPTPROBES | |
| 48 | 47 | depends on !PREEMPT |
| 49 | - depends on HAVE_OPTPROBES | |
| 50 | 48 | select KALLSYMS_ALL |
| 51 | - help | |
| 52 | - This option will allow kprobes to optimize breakpoint to | |
| 53 | - a jump for reducing its overhead. | |
| 54 | 49 | |
| 55 | 50 | config HAVE_EFFICIENT_UNALIGNED_ACCESS |
| 56 | 51 | bool |