[PATCH v2 3/3] page-types: exit early when invoked with -d|--describe

From: Alex Chiang
Date: Thu Nov 05 2009 - 15:21:36 EST

On a system with large amount of memory (256GB), invoking page-types
can take quite a long time, which is unreasonable considering the user
only wants a description of the flags:

# time ./page-types -d 0x10
0x0000000000000010 ____D_____________________________ dirty

real 0m34.285s
user 0m1.966s
sys 0m32.313s

This is because we still walk the entire address range.

Exiting early seems like a reasonble solution:

# time ./page-types -d 0x10
0x0000000000000010 ____D_____________________________ dirty

real 0m0.007s
user 0m0.001s
sys 0m0.005s

Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Cc: Haicheng Li <haicheng.li@xxxxxxxxx>
Signed-off-by: Alex Chiang <achiang@xxxxxx>

Documentation/vm/page-types.c | 3 +--
1 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/Documentation/vm/page-types.c b/Documentation/vm/page-types.c
index 9c09eb5..9cf50ab 100644
--- a/Documentation/vm/page-types.c
+++ b/Documentation/vm/page-types.c
@@ -940,9 +940,8 @@ int main(int argc, char *argv[])
case 'd':
- opt_no_summary = 1;
- break;
+ exit(0);
case 'l':
opt_list = 1;

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