The patch titled
Subject: lib/lz4/lz4_decompress.c: pull out constant tables
has been added to the -mm tree. Its filename is
lib-lz4-pull-out-constant-tables.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/lib-lz4-pull-out-constant-tables.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/lib-lz4-pull-out-constant-tables.patch
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------------------------------------------------------
From: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Subject: lib/lz4/lz4_decompress.c: pull out constant tables
There's no reason to allocate the dec{32,64}table on the stack; it just
wastes a bunch of instructions setting them up and, of course, also
consumes quite a bit of stack. Using size_t for such small integers is a
little excessive.
$ scripts/bloat-o-meter /tmp/built-in.o lib/built-in.o
add/remove: 2/2 grow/shrink: 2/0 up/down: 1304/-1548 (-244)
function old new delta
lz4_decompress_unknownoutputsize 55 718 +663
lz4_decompress 55 632 +577
dec64table - 32 +32
dec32table - 32 +32
lz4_uncompress 747 - -747
lz4_uncompress_unknownoutputsize 801 - -801
The now inlined lz4_uncompress functions used to have a stack footprint of
176 bytes (according to -fstack-usage); their inlinees have increased
their stack use from 32 bytes to 48 and 80 bytes, respectively.
Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Cc: Kyungsik Lee <kyungsik.lee@xxxxxxx>
Cc: Yann Collet <yann.collet.73@xxxxxxxxx>
Cc: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
Cc: Richard Laager <rlaager@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/lz4/lz4_decompress.c | 18 +++++++-----------
1 file changed, 7 insertions(+), 11 deletions(-)
diff -puN lib/lz4/lz4_decompress.c~lib-lz4-pull-out-constant-tables lib/lz4/lz4_decompress.c
--- a/lib/lz4/lz4_decompress.c~lib-lz4-pull-out-constant-tables
+++ a/lib/lz4/lz4_decompress.c
@@ -47,6 +47,11 @@
#include "lz4defs.h"
+static const int dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0};
+#if LZ4_ARCH64
+static const int dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3};
+#endif
+
static int lz4_uncompress(const char *source, char *dest, int osize)
{
const BYTE *ip = (const BYTE *) source;
@@ -56,10 +61,6 @@ static int lz4_uncompress(const char *so
BYTE *cpy;
unsigned token;
size_t length;
- size_t dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0};
-#if LZ4_ARCH64
- size_t dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3};
-#endif
while (1) {
@@ -116,7 +117,7 @@ static int lz4_uncompress(const char *so
/* copy repeated sequence */
if (unlikely((op - ref) < STEPSIZE)) {
#if LZ4_ARCH64
- size_t dec64 = dec64table[op - ref];
+ int dec64 = dec64table[op - ref];
#else
const int dec64 = 0;
#endif
@@ -174,11 +175,6 @@ static int lz4_uncompress_unknownoutputs
BYTE * const oend = op + maxoutputsize;
BYTE *cpy;
- size_t dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0};
-#if LZ4_ARCH64
- size_t dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3};
-#endif
-
/* Main Loop */
while (ip < iend) {
@@ -246,7 +242,7 @@ static int lz4_uncompress_unknownoutputs
/* copy repeated sequence */
if (unlikely((op - ref) < STEPSIZE)) {
#if LZ4_ARCH64
- size_t dec64 = dec64table[op - ref];
+ int dec64 = dec64table[op - ref];
#else
const int dec64 = 0;
#endif
_
Patches currently in -mm which might be from linux@xxxxxxxxxxxxxxxxxx are
origin.patch
linux-bitmaph-improve-bitmap_lastfirst_word_mask.patch
lib-lz4-pull-out-constant-tables.patch
linux-next.patch
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