summaryrefslogtreecommitdiffstats
path: root/arch/arm/kernel
diff options
context:
space:
mode:
authorPhil Carmody <ext-phil.2.carmody@nokia.com>2010-08-19 15:20:37 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2010-09-02 15:31:36 +0100
commit5333a3de3cdd739ec4f6d501f5f6d09bab7ff919 (patch)
tree3c3c2a746c219660f1401f1172d1bdfee3d8a931 /arch/arm/kernel
parent09e56a2d076c2afb2a1932ae4283e10ef2d26ef3 (diff)
downloadblackbird-op-linux-5333a3de3cdd739ec4f6d501f5f6d09bab7ff919.tar.gz
blackbird-op-linux-5333a3de3cdd739ec4f6d501f5f6d09bab7ff919.zip
ARM: 6341/1: unwind - optimise linked-list searches for modules
With several sections per module, and 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 reduces the number of steps in the search to barely more than 1. Signed-off-by: Phil Carmody <ext-phil.2.carmody@nokia.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/kernel')
-rw-r--r--arch/arm/kernel/unwind.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/arm/kernel/unwind.c b/arch/arm/kernel/unwind.c
index dd81a918c106..2a161765f6d5 100644
--- a/arch/arm/kernel/unwind.c
+++ b/arch/arm/kernel/unwind.c
@@ -146,6 +146,8 @@ static struct unwind_idx *unwind_find_idx(unsigned long addr)
addr < table->end_addr) {
idx = search_index(addr, table->start,
table->stop - 1);
+ /* Move-to-front to exploit common traces */
+ list_move(&table->list, &unwind_tables);
break;
}
}
OpenPOWER on IntegriCloud