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authorPhil Carmody <ext-phil.2.carmody@nokia.com>2010-09-10 10:47:59 (GMT)
committerKyle McMartin <kyle@mcmartin.ca>2010-10-22 01:12:19 (GMT)
commitb1b1d4a6f244eb9513f006a188f7ed30d5014de5 (patch)
tree7fbdf118088f9d3746f384ea26312548ba5719dd /arch/parisc
parentf720817700de48a57f54535a5dd9783cca2d2d6b (diff)
downloadlinux-b1b1d4a6f244eb9513f006a188f7ed30d5014de5.tar.xz
parisc: unwind - optimise linked-list searches for modules
Having many dozens of modules, the searches down the linked list of sections would dominate the lookup time, dwarfing any savings from the binary search within the section. A simple move-to-front optimisation exploits the commonality of the code paths taken, and in simple real-world tests on other architectures reduced the number of steps in the search to barely more than 1. Signed-off-by: Phil Carmody <ext-phil.2.carmody@nokia.com> Signed-off-by: Kyle McMartin <kyle@redhat.com>
Diffstat (limited to 'arch/parisc')
-rw-r--r--arch/parisc/kernel/unwind.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/parisc/kernel/unwind.c b/arch/parisc/kernel/unwind.c
index d58eac1..76ed62e 100644
--- a/arch/parisc/kernel/unwind.c
+++ b/arch/parisc/kernel/unwind.c
@@ -80,8 +80,11 @@ find_unwind_entry(unsigned long addr)
if (addr >= table->start &&
addr <= table->end)
e = find_unwind_entry_in_table(table, addr);
- if (e)
+ if (e) {
+ /* Move-to-front to exploit common traces */
+ list_move(&table->list, &unwind_tables);
break;
+ }
}
return e;