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Subject[PATCH] cpumask 3/10 bitmap inlining and optimizations
cpumask 3/10 bitmap inlining and optimizations

These bitmap improvements make it a suitable basis for
fully supporting cpumask_t and nodemask_t. Inline macros
with compile-time checks enable generating tight code on
both small and large systems (large meaning cpumask_t
requires more than one unsigned long's worth of bits).

The existing bitmap_<op> macros in lib/bitmap.c
are renamed to __bitmap_<op>, and wrappers for each
bitmap_<op> are exposed in include/linux/bitmap.h

This patch _includes_ Bill Irwins rewrite of the
bitmap_shift operators to not require a fixed length
intermediate bitmap.

Improved comments list each available operator for easy
browsing.

include/linux/bitmap.h | 266 ++++++++++++++++++++++----
lib/bitmap.c | 91 ++++----
2 files changed, 276 insertions(+), 81 deletions(-)
Signed-off-by: Paul Jackson <pj@sgi.com>


Index: 2.6.7-rc2-mm2/include/linux/bitmap.h
===================================================================
--- 2.6.7-rc2-mm2.orig/include/linux/bitmap.h 2004-06-03 05:56:31.000000000 -0700
+++ 2.6.7-rc2-mm2/include/linux/bitmap.h 2004-06-03 05:57:06.000000000 -0700
@@ -3,57 +3,249 @@

#ifndef __ASSEMBLY__

-#include <linux/config.h>
-#include <linux/compiler.h>
#include <linux/types.h>
-#include <linux/kernel.h>
#include <linux/bitops.h>
#include <linux/string.h>

-int bitmap_empty(const unsigned long *bitmap, int bits);
-int bitmap_full(const unsigned long *bitmap, int bits);
-int bitmap_equal(const unsigned long *bitmap1,
- const unsigned long *bitmap2, int bits);
-void bitmap_complement(unsigned long *dst, const unsigned long *src, int bits);
+/*
+ * bitmaps provide bit arrays that consume one or more unsigned
+ * longs. The bitmap interface and available operations are listed
+ * here, in bitmap.h
+ *
+ * Function implementations generic to all architectures are in
+ * lib/bitmap.c. Functions implementations that are architecture
+ * specific are in various include/asm-<arch>/bitops.h headers
+ * and other arch/<arch> specific files.
+ *
+ * See lib/bitmap.c for more details.
+ */
+
+/*
+ * The available bitmap operations and their rough meaning in the
+ * case that the bitmap is a single unsigned long are thus:
+ *
+ * bitmap_zero(dst, nbits) *dst = 0UL
+ * bitmap_fill(dst, nbits) *dst = ~0UL
+ * bitmap_copy(dst, src, nbits) *dst = *src
+ * bitmap_and(dst, src1, src2, nbits) *dst = *src1 & *src2
+ * bitmap_or(dst, src1, src2, nbits) *dst = *src1 | *src2
+ * bitmap_xor(dst, src1, src2, nbits) *dst = *src1 ^ *src2
+ * bitmap_andnot(dst, src1, src2, nbits) *dst = *src1 & ~(*src2)
+ * bitmap_complement(dst, src, nbits) *dst = ~(*src)
+ * bitmap_equal(src1, src2, nbits) Are *src1 and *src2 equal?
+ * bitmap_intersects(src1, src2, nbits) Do *src1 and *src2 overlap?
+ * bitmap_subset(src1, src2, nbits) Is *src1 a subset of *src2?
+ * bitmap_empty(src, nbits) Are all bits zero in *src?
+ * bitmap_full(src, nbits) Are all bits set in *src?
+ * bitmap_weight(src, nbits) Hamming Weight: number set bits
+ * bitmap_shift_right(dst, src, n, nbits) *dst = *src >> n
+ * bitmap_shift_left(dst, src, n, nbits) *dst = *src << n
+ * bitmap_scnprintf(buf, len, src, nbits) Print bitmap src to buf
+ * bitmap_parse(ubuf, ulen, dst, nbits) Parse bitmap dst from buf
+ */
+
+/*
+ * Also the following operations in asm/bitops.h apply to bitmaps.
+ *
+ * set_bit(bit, addr) *addr |= bit
+ * clear_bit(bit, addr) *addr &= ~bit
+ * change_bit(bit, addr) *addr ^= bit
+ * test_bit(bit, addr) Is bit set in *addr?
+ * test_and_set_bit(bit, addr) Set bit and return old value
+ * test_and_clear_bit(bit, addr) Clear bit and return old value
+ * test_and_change_bit(bit, addr) Change bit and return old value
+ * find_first_zero_bit(addr, nbits) Position first zero bit in *addr
+ * find_first_bit(addr, nbits) Position first set bit in *addr
+ * find_next_zero_bit(addr, nbits, bit) Position next zero bit in *addr >= bit
+ * find_next_bit(addr, nbits, bit) Position next set bit in *addr >= bit
+ */
+
+/*
+ * The DECLARE_BITMAP(name,bits) macro, in linux/types.h, can be used
+ * to declare an array named 'name' of just enough unsigned longs to
+ * contain all bit positions from 0 to 'bits' - 1.
+ */
+
+/*
+ * lib/bitmap.c provides these functions:
+ */
+
+extern int __bitmap_empty(const unsigned long *bitmap, int bits);
+extern int __bitmap_full(const unsigned long *bitmap, int bits);
+extern int __bitmap_equal(const unsigned long *bitmap1,
+ const unsigned long *bitmap2, int bits);
+extern void __bitmap_complement(unsigned long *dst, const unsigned long *src,
+ int bits);
+extern void __bitmap_shift_right(unsigned long *dst,
+ const unsigned long *src, int shift, int bits);
+extern void __bitmap_shift_left(unsigned long *dst,
+ const unsigned long *src, int shift, int bits);
+extern void __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
+ const unsigned long *bitmap2, int bits);
+extern void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
+ const unsigned long *bitmap2, int bits);
+extern void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
+ const unsigned long *bitmap2, int bits);
+extern void __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
+ const unsigned long *bitmap2, int bits);
+extern int __bitmap_intersects(const unsigned long *bitmap1,
+ const unsigned long *bitmap2, int bits);
+extern int __bitmap_subset(const unsigned long *bitmap1,
+ const unsigned long *bitmap2, int bits);
+extern int __bitmap_weight(const unsigned long *bitmap, int bits);
+
+extern int bitmap_scnprintf(char *buf, unsigned int len,
+ const unsigned long *src, int nbits);
+extern int bitmap_parse(const char __user *ubuf, unsigned int ulen,
+ unsigned long *dst, int nbits);
+
+#define BITMAP_LAST_WORD_MASK(nbits) \
+( \
+ ((nbits) % BITS_PER_LONG) ? \
+ (1UL<<((nbits) % BITS_PER_LONG))-1 : ~0UL \
+)

-static inline void bitmap_zero(unsigned long *bitmap, int bits)
+static inline void bitmap_zero(unsigned long *dst, int nbits)
{
- memset(bitmap, 0, BITS_TO_LONGS(bits)*sizeof(unsigned long));
+ if (nbits <= BITS_PER_LONG)
+ *dst = 0UL;
+ else {
+ int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
+ memset(dst, 0, len);
+ }
}

-static inline void bitmap_fill(unsigned long *bitmap, int bits)
+static inline void bitmap_fill(unsigned long *dst, int nbits)
{
- memset(bitmap, 0xff, BITS_TO_LONGS(bits)*sizeof(unsigned long));
+ size_t nlongs = BITS_TO_LONGS(nbits);
+ if (nlongs > 1) {
+ int len = (nlongs - 1) * sizeof(unsigned long);
+ memset(dst, 0xff, len);
+ }
+ dst[nlongs - 1] = BITMAP_LAST_WORD_MASK(nbits);
}

-static inline void bitmap_copy(unsigned long *dst,
- const unsigned long *src, int bits)
+static inline void bitmap_copy(unsigned long *dst, const unsigned long *src,
+ int nbits)
{
- int len = BITS_TO_LONGS(bits)*sizeof(unsigned long);
- memcpy(dst, src, len);
+ if (nbits <= BITS_PER_LONG)
+ *dst = *src;
+ else {
+ int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
+ memcpy(dst, src, len);
+ }
}

-void bitmap_shift_right(unsigned long *dst,
- const unsigned long *src, int shift, int bits);
-void bitmap_shift_left(unsigned long *dst,
- const unsigned long *src, int shift, int bits);
-void bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
- const unsigned long *bitmap2, int bits);
-void bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
- const unsigned long *bitmap2, int bits);
-void bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
- const unsigned long *bitmap2, int bits);
-void bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
- const unsigned long *bitmap2, int bits);
-int bitmap_intersects(const unsigned long *bitmap1,
- const unsigned long *bitmap2, int bits);
-int bitmap_subset(const unsigned long *bitmap1,
- const unsigned long *bitmap2, int bits);
-int bitmap_weight(const unsigned long *bitmap, int bits);
-int bitmap_scnprintf(char *buf, unsigned int buflen,
- const unsigned long *maskp, int bits);
-int bitmap_parse(const char __user *ubuf, unsigned int ubuflen,
- unsigned long *maskp, int bits);
+static inline void bitmap_and(unsigned long *dst, const unsigned long *src1,
+ const unsigned long *src2, int nbits)
+{
+ if (nbits <= BITS_PER_LONG)
+ *dst = *src1 & *src2;
+ else
+ __bitmap_and(dst, src1, src2, nbits);
+}
+
+static inline void bitmap_or(unsigned long *dst, const unsigned long *src1,
+ const unsigned long *src2, int nbits)
+{
+ if (nbits <= BITS_PER_LONG)
+ *dst = *src1 | *src2;
+ else
+ __bitmap_or(dst, src1, src2, nbits);
+}
+
+static inline void bitmap_xor(unsigned long *dst, const unsigned long *src1,
+ const unsigned long *src2, int nbits)
+{
+ if (nbits <= BITS_PER_LONG)
+ *dst = *src1 ^ *src2;
+ else
+ __bitmap_xor(dst, src1, src2, nbits);
+}
+
+static inline void bitmap_andnot(unsigned long *dst, const unsigned long *src1,
+ const unsigned long *src2, int nbits)
+{
+ if (nbits <= BITS_PER_LONG)
+ *dst = *src1 & ~(*src2);
+ else
+ __bitmap_andnot(dst, src1, src2, nbits);
+}
+
+static inline void bitmap_complement(unsigned long *dst, const unsigned long *src,
+ int nbits)
+{
+ if (nbits <= BITS_PER_LONG)
+ *dst = ~(*src) & BITMAP_LAST_WORD_MASK(nbits);
+ else
+ __bitmap_complement(dst, src, nbits);
+}
+
+static inline int bitmap_equal(const unsigned long *src1,
+ const unsigned long *src2, int nbits)
+{
+ if (nbits <= BITS_PER_LONG)
+ return ! ((*src1 ^ *src2) & BITMAP_LAST_WORD_MASK(nbits));
+ else
+ return __bitmap_equal(src1, src2, nbits);
+}
+
+static inline int bitmap_intersects(const unsigned long *src1,
+ const unsigned long *src2, int nbits)
+{
+ if (nbits <= BITS_PER_LONG)
+ return ((*src1 & *src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;
+ else
+ return __bitmap_intersects(src1, src2, nbits);
+}
+
+static inline int bitmap_subset(const unsigned long *src1,
+ const unsigned long *src2, int nbits)
+{
+ if (nbits <= BITS_PER_LONG)
+ return ! ((*src1 & ~(*src2)) & BITMAP_LAST_WORD_MASK(nbits));
+ else
+ return __bitmap_subset(src1, src2, nbits);
+}
+
+static inline int bitmap_empty(const unsigned long *src, int nbits)
+{
+ if (nbits <= BITS_PER_LONG)
+ return ! (*src & BITMAP_LAST_WORD_MASK(nbits));
+ else
+ return __bitmap_empty(src, nbits);
+}
+
+static inline int bitmap_full(const unsigned long *src, int nbits)
+{
+ if (nbits <= BITS_PER_LONG)
+ return ! (~(*src) & BITMAP_LAST_WORD_MASK(nbits));
+ else
+ return __bitmap_full(src, nbits);
+}
+
+static inline int bitmap_weight(const unsigned long *src, int nbits)
+{
+ return __bitmap_weight(src, nbits);
+}
+
+static inline void bitmap_shift_right(unsigned long *dst,
+ const unsigned long *src, int n, int nbits)
+{
+ if (nbits <= BITS_PER_LONG)
+ *dst = *src >> n;
+ else
+ __bitmap_shift_right(dst, src, n, nbits);
+}
+
+static inline void bitmap_shift_left(unsigned long *dst,
+ const unsigned long *src, int n, int nbits)
+{
+ if (nbits <= BITS_PER_LONG)
+ *dst = (*src << n) & BITMAP_LAST_WORD_MASK(nbits);
+ else
+ __bitmap_shift_left(dst, src, n, nbits);
+}

#endif /* __ASSEMBLY__ */

Index: 2.6.7-rc2-mm2/lib/bitmap.c
===================================================================
--- 2.6.7-rc2-mm2.orig/lib/bitmap.c 2004-06-03 05:56:31.000000000 -0700
+++ 2.6.7-rc2-mm2/lib/bitmap.c 2004-06-03 05:57:06.000000000 -0700
@@ -15,7 +15,8 @@
/*
* bitmaps provide an array of bits, implemented using an an
* array of unsigned longs. The number of valid bits in a
- * given bitmap need not be an exact multiple of BITS_PER_LONG.
+ * given bitmap does _not_ need to be an exact multiple of
+ * BITS_PER_LONG.
*
* The possible unused bits in the last, partially used word
* of a bitmap are 'don't care'. The implementation makes
@@ -30,9 +31,14 @@
* if you don't input any bitmaps to these ops that have some
* unused bits set, then they won't output any set unused bits
* in output bitmaps.
+ *
+ * The byte ordering of bitmaps is more natural on little
+ * endian architectures. See the big-endian headers
+ * include/asm-ppc64/bitops.h and include/asm-s390/bitops.h
+ * for the best explanations of this ordering.
*/

-int bitmap_empty(const unsigned long *bitmap, int bits)
+int __bitmap_empty(const unsigned long *bitmap, int bits)
{
int k, lim = bits/BITS_PER_LONG;
for (k = 0; k < lim; ++k)
@@ -40,14 +46,14 @@
return 0;

if (bits % BITS_PER_LONG)
- if (bitmap[k] & ((1UL << (bits % BITS_PER_LONG)) - 1))
+ if (bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
return 0;

return 1;
}
-EXPORT_SYMBOL(bitmap_empty);
+EXPORT_SYMBOL(__bitmap_empty);

-int bitmap_full(const unsigned long *bitmap, int bits)
+int __bitmap_full(const unsigned long *bitmap, int bits)
{
int k, lim = bits/BITS_PER_LONG;
for (k = 0; k < lim; ++k)
@@ -55,14 +61,14 @@
return 0;

if (bits % BITS_PER_LONG)
- if (~bitmap[k] & ((1UL << (bits % BITS_PER_LONG)) - 1))
+ if (~bitmap[k] & BITMAP_LAST_WORD_MASK(bits))
return 0;

return 1;
}
-EXPORT_SYMBOL(bitmap_full);
+EXPORT_SYMBOL(__bitmap_full);

-int bitmap_equal(const unsigned long *bitmap1,
+int __bitmap_equal(const unsigned long *bitmap1,
const unsigned long *bitmap2, int bits)
{
int k, lim = bits/BITS_PER_LONG;
@@ -71,27 +77,26 @@
return 0;

if (bits % BITS_PER_LONG)
- if ((bitmap1[k] ^ bitmap2[k]) &
- ((1UL << (bits % BITS_PER_LONG)) - 1))
+ if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
return 0;

return 1;
}
-EXPORT_SYMBOL(bitmap_equal);
+EXPORT_SYMBOL(__bitmap_equal);

-void bitmap_complement(unsigned long *dst, const unsigned long *src, int bits)
+void __bitmap_complement(unsigned long *dst, const unsigned long *src, int bits)
{
int k, lim = bits/BITS_PER_LONG;
for (k = 0; k < lim; ++k)
dst[k] = ~src[k];

if (bits % BITS_PER_LONG)
- dst[k] = ~src[k] & ((1UL << (bits % BITS_PER_LONG)) - 1);
+ dst[k] = ~src[k] & BITMAP_LAST_WORD_MASK(bits);
}
-EXPORT_SYMBOL(bitmap_complement);
+EXPORT_SYMBOL(__bitmap_complement);

/*
- * bitmap_shift_right - logical right shift of the bits in a bitmap
+ * __bitmap_shift_right - logical right shift of the bits in a bitmap
* @dst - destination bitmap
* @src - source bitmap
* @nbits - shift by this many bits
@@ -101,7 +106,7 @@
* direction. Zeros are fed into the vacated MS positions and the
* LS bits shifted off the bottom are lost.
*/
-void bitmap_shift_right(unsigned long *dst,
+void __bitmap_shift_right(unsigned long *dst,
const unsigned long *src, int shift, int bits)
{
int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
@@ -131,10 +136,11 @@
if (off)
memset(&dst[lim - off], 0, off*sizeof(unsigned long));
}
-EXPORT_SYMBOL(bitmap_shift_right);
+EXPORT_SYMBOL(__bitmap_shift_right);
+

/*
- * bitmap_shift_left - logical left shift of the bits in a bitmap
+ * __bitmap_shift_left - logical left shift of the bits in a bitmap
* @dst - destination bitmap
* @src - source bitmap
* @nbits - shift by this many bits
@@ -144,7 +150,8 @@
* direction. Zeros are fed into the vacated LS bit positions
* and those MS bits shifted off the top are lost.
*/
-void bitmap_shift_left(unsigned long *dst,
+
+void __bitmap_shift_left(unsigned long *dst,
const unsigned long *src, int shift, int bits)
{
int k, lim = BITS_TO_LONGS(bits), left = bits % BITS_PER_LONG;
@@ -170,9 +177,9 @@
if (off)
memset(dst, 0, off*sizeof(unsigned long));
}
-EXPORT_SYMBOL(bitmap_shift_left);
+EXPORT_SYMBOL(__bitmap_shift_left);

-void bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
+void __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
const unsigned long *bitmap2, int bits)
{
int k;
@@ -181,9 +188,9 @@
for (k = 0; k < nr; k++)
dst[k] = bitmap1[k] & bitmap2[k];
}
-EXPORT_SYMBOL(bitmap_and);
+EXPORT_SYMBOL(__bitmap_and);

-void bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
+void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
const unsigned long *bitmap2, int bits)
{
int k;
@@ -192,9 +199,9 @@
for (k = 0; k < nr; k++)
dst[k] = bitmap1[k] | bitmap2[k];
}
-EXPORT_SYMBOL(bitmap_or);
+EXPORT_SYMBOL(__bitmap_or);

-void bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
+void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
const unsigned long *bitmap2, int bits)
{
int k;
@@ -203,9 +210,9 @@
for (k = 0; k < nr; k++)
dst[k] = bitmap1[k] ^ bitmap2[k];
}
-EXPORT_SYMBOL(bitmap_xor);
+EXPORT_SYMBOL(__bitmap_xor);

-void bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
+void __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
const unsigned long *bitmap2, int bits)
{
int k;
@@ -214,9 +221,9 @@
for (k = 0; k < nr; k++)
dst[k] = bitmap1[k] & ~bitmap2[k];
}
-EXPORT_SYMBOL(bitmap_andnot);
+EXPORT_SYMBOL(__bitmap_andnot);

-int bitmap_intersects(const unsigned long *bitmap1,
+int __bitmap_intersects(const unsigned long *bitmap1,
const unsigned long *bitmap2, int bits)
{
int k, lim = bits/BITS_PER_LONG;
@@ -225,14 +232,13 @@
return 1;

if (bits % BITS_PER_LONG)
- if ((bitmap1[k] & bitmap2[k]) &
- ((1UL << (bits % BITS_PER_LONG)) - 1))
+ if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
return 1;
return 0;
}
-EXPORT_SYMBOL(bitmap_intersects);
+EXPORT_SYMBOL(__bitmap_intersects);

-int bitmap_subset(const unsigned long *bitmap1,
+int __bitmap_subset(const unsigned long *bitmap1,
const unsigned long *bitmap2, int bits)
{
int k, lim = bits/BITS_PER_LONG;
@@ -241,15 +247,14 @@
return 0;

if (bits % BITS_PER_LONG)
- if ((bitmap1[k] & ~bitmap2[k]) &
- ((1UL << (bits % BITS_PER_LONG)) - 1))
+ if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
return 0;
return 1;
}
-EXPORT_SYMBOL(bitmap_subset);
+EXPORT_SYMBOL(__bitmap_subset);

#if BITS_PER_LONG == 32
-int bitmap_weight(const unsigned long *bitmap, int bits)
+int __bitmap_weight(const unsigned long *bitmap, int bits)
{
int k, w = 0, lim = bits/BITS_PER_LONG;

@@ -257,13 +262,12 @@
w += hweight32(bitmap[k]);

if (bits % BITS_PER_LONG)
- w += hweight32(bitmap[k] &
- ((1UL << (bits % BITS_PER_LONG)) - 1));
+ w += hweight32(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));

return w;
}
#else
-int bitmap_weight(const unsigned long *bitmap, int bits)
+int __bitmap_weight(const unsigned long *bitmap, int bits)
{
int k, w = 0, lim = bits/BITS_PER_LONG;

@@ -271,13 +275,12 @@
w += hweight64(bitmap[k]);

if (bits % BITS_PER_LONG)
- w += hweight64(bitmap[k] &
- ((1UL << (bits % BITS_PER_LONG)) - 1));
+ w += hweight64(bitmap[k] & BITMAP_LAST_WORD_MASK(bits));

return w;
}
#endif
-EXPORT_SYMBOL(bitmap_weight);
+EXPORT_SYMBOL(__bitmap_weight);

/*
* Bitmap printing & parsing functions: first version by Bill Irwin,
@@ -394,7 +397,7 @@
if (nchunks == 0 && chunk == 0)
continue;

- bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits);
+ __bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits);
*maskp |= chunk;
nchunks++;
nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ;

--
I won't rest till it's the best ...
Programmer, Linux Scalability
Paul Jackson <pj@sgi.com> 1.650.933.1373
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