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| author | Oleg Nesterov <oleg@redhat.com> | 2012-05-29 21:27:44 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2012-06-06 17:13:59 +0200 |
| commit | c00b275043adc14d668f36266b890f0c53d46640 (patch) | |
| tree | cdb6db30f3f0d18049079d7a014f6561e056eb06 /kernel | |
| parent | 436d03faf6961b30e13b2d0967aea9d772d6cf44 (diff) | |
| download | linux-c00b275043adc14d668f36266b890f0c53d46640.tar.gz linux-c00b275043adc14d668f36266b890f0c53d46640.tar.bz2 linux-c00b275043adc14d668f36266b890f0c53d46640.zip | |
uprobes: Optimize is_swbp_at_addr() for current->mm
Change is_swbp_at_addr() to try to avoid the costly
read_opcode() if mm == current->mm, __copy_from_user_inatomic()
should succeed in the likely case.
Currently this optimization is not important, but we are going
to add more is_swbp_at_addr(current->mm) callers.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120529192744.GA8057@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/events/uprobes.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 985be4d80fe8..d0f5ec0dcdea 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -333,10 +333,20 @@ static int is_swbp_at_addr(struct mm_struct *mm, unsigned long vaddr) uprobe_opcode_t opcode; int result; + if (current->mm == mm) { + pagefault_disable(); + result = __copy_from_user_inatomic(&opcode, (void __user*)vaddr, + sizeof(opcode)); + pagefault_enable(); + + if (likely(result == 0)) + goto out; + } + result = read_opcode(mm, vaddr, &opcode); if (result) return result; - +out: if (is_swbp_insn(&opcode)) return 1; |