]> pilppa.com Git - linux-2.6-omap-h63xx.git/commit
[PATCH] kprobes: enable booster on the preemptible kernel
authorMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Thu, 7 Dec 2006 04:38:11 +0000 (20:38 -0800)
committerLinus Torvalds <torvalds@woody.osdl.org>
Thu, 7 Dec 2006 16:39:38 +0000 (08:39 -0800)
commitb4c6c34a530b4d1c626f4ac0a884e0a9b849378c
tree5705a4621b6668bced1969396465800256d76c76
parentc15bb296403f1ce448384d58742e0dc04f49d664
[PATCH] kprobes: enable booster on the preemptible kernel

When we are unregistering a kprobe-booster, we can't release its
instruction buffer immediately on the preemptive kernel, because some
processes might be preempted on the buffer.  The freeze_processes() and
thaw_processes() functions can clean most of processes up from the buffer.
There are still some non-frozen threads who have the PF_NOFREEZE flag.  If
those threads are sleeping (not preempted) at the known place outside the
buffer, we can ensure safety of freeing.

However, the processing of this check routine takes a long time.  So, this
patch introduces the garbage collection mechanism of insn_slot.  It also
introduces the "dirty" flag to free_insn_slot because of efficiency.

The "clean" instruction slots (dirty flag is cleared) are released
immediately.  But the "dirty" slots which are used by boosted kprobes, are
marked as garbages.  collect_garbage_slots() will be invoked to release
"dirty" slots if there are more than INSNS_PER_PAGE garbage slots or if
there are no unused slots.

Cc: "Keshavamurthy, Anil S" <anil.s.keshavamurthy@intel.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: "bibo,mao" <bibo.mao@intel.com>
Cc: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Cc: Yumiko Sugita <yumiko.sugita.yf@hitachi.com>
Cc: Satoshi Oshima <soshima@redhat.com>
Cc: Hideo Aoki <haoki@redhat.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
arch/i386/kernel/kprobes.c
arch/ia64/kernel/kprobes.c
arch/powerpc/kernel/kprobes.c
arch/s390/kernel/kprobes.c
arch/x86_64/kernel/kprobes.c
include/linux/kprobes.h
kernel/kprobes.c