[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH] x86/bitmap: Even more signed-ness fixes
Further to commit 558e84b7ffec ("xen/bitmap: Consistently use unsigned bits values"), it turns out that GCC's range analysis isn't good enough to notice that 'bits / BITS_PER_LONG' is always within the unsigned range of k. As a consequence, it re-sign-extends 'k' when calculating the pointer holding 'bitmap[k]' on each loop iteration. Switch all internal variables to unsigned int, which allows for better-still code generation. Also clean up the prototypes for __bitmap_{set,clear} and the *_region() helpers, along with the internal variables. Bloat-o-meter for a random x86 build reports: add/remove: 0/0 grow/shrink: 0/10 up/down: 0/-277 (-277) No functional change. Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> --- CC: George Dunlap <George.Dunlap@xxxxxxxxxx> CC: Jan Beulich <JBeulich@xxxxxxxx> CC: Stefano Stabellini <sstabellini@xxxxxxxxxx> CC: Wei Liu <wl@xxxxxxx> CC: Julien Grall <julien@xxxxxxx> Full bloat-o-meter details: add/remove: 0/0 grow/shrink: 0/10 up/down: 0/-277 (-277) Function old new delta __bitmap_equal 105 102 -3 bitmap_find_free_region 135 129 -6 __bitmap_subset 121 115 -6 __bitmap_intersects 105 99 -6 __bitmap_full 91 85 -6 __bitmap_empty 90 84 -6 bitmap_release_region 68 45 -23 bitmap_allocate_region 104 72 -32 __bitmap_clear 136 43 -93 __bitmap_set 136 40 -96 Total: Before=4063985, After=4063708, chg -0.01% Other functions have changes, but no net change. --- xen/common/bitmap.c | 76 ++++++++++++++++++++++------------------ xen/include/xen/bitmap.h | 15 ++++---- 2 files changed, 50 insertions(+), 41 deletions(-) diff --git a/xen/common/bitmap.c b/xen/common/bitmap.c index 9d9ff09f3dde..18e23e2f0e18 100644 --- a/xen/common/bitmap.c +++ b/xen/common/bitmap.c @@ -57,7 +57,8 @@ static void clamp_last_byte(uint8_t *bp, unsigned int nbits) int __bitmap_empty(const unsigned long *bitmap, unsigned int bits) { - int k, lim = bits/BITS_PER_LONG; + unsigned int k, lim = bits / BITS_PER_LONG; + for (k = 0; k < lim; ++k) if (bitmap[k]) return 0; @@ -72,7 +73,8 @@ EXPORT_SYMBOL(__bitmap_empty); int __bitmap_full(const unsigned long *bitmap, unsigned int bits) { - int k, lim = bits/BITS_PER_LONG; + unsigned int k, lim = bits / BITS_PER_LONG; + for (k = 0; k < lim; ++k) if (~bitmap[k]) return 0; @@ -88,7 +90,8 @@ EXPORT_SYMBOL(__bitmap_full); int __bitmap_equal(const unsigned long *bitmap1, const unsigned long *bitmap2, unsigned int bits) { - int k, lim = bits/BITS_PER_LONG; + unsigned int k, lim = bits / BITS_PER_LONG; + for (k = 0; k < lim; ++k) if (bitmap1[k] != bitmap2[k]) return 0; @@ -103,7 +106,8 @@ EXPORT_SYMBOL(__bitmap_equal); void __bitmap_complement(unsigned long *dst, const unsigned long *src, unsigned int bits) { - int k, lim = bits/BITS_PER_LONG; + unsigned int k, lim = bits / BITS_PER_LONG; + for (k = 0; k < lim; ++k) dst[k] = ~src[k]; @@ -115,8 +119,7 @@ EXPORT_SYMBOL(__bitmap_complement); void __bitmap_and(unsigned long *dst, const unsigned long *bitmap1, const unsigned long *bitmap2, unsigned int bits) { - int k; - int nr = BITS_TO_LONGS(bits); + unsigned int k, nr = BITS_TO_LONGS(bits); for (k = 0; k < nr; k++) dst[k] = bitmap1[k] & bitmap2[k]; @@ -126,8 +129,7 @@ EXPORT_SYMBOL(__bitmap_and); void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1, const unsigned long *bitmap2, unsigned int bits) { - int k; - int nr = BITS_TO_LONGS(bits); + unsigned int k, nr = BITS_TO_LONGS(bits); for (k = 0; k < nr; k++) dst[k] = bitmap1[k] | bitmap2[k]; @@ -137,8 +139,7 @@ EXPORT_SYMBOL(__bitmap_or); void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1, const unsigned long *bitmap2, unsigned int bits) { - int k; - int nr = BITS_TO_LONGS(bits); + unsigned int k, nr = BITS_TO_LONGS(bits); for (k = 0; k < nr; k++) dst[k] = bitmap1[k] ^ bitmap2[k]; @@ -148,8 +149,7 @@ EXPORT_SYMBOL(__bitmap_xor); void __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1, const unsigned long *bitmap2, unsigned int bits) { - int k; - int nr = BITS_TO_LONGS(bits); + unsigned int k, nr = BITS_TO_LONGS(bits); for (k = 0; k < nr; k++) dst[k] = bitmap1[k] & ~bitmap2[k]; @@ -159,7 +159,8 @@ EXPORT_SYMBOL(__bitmap_andnot); int __bitmap_intersects(const unsigned long *bitmap1, const unsigned long *bitmap2, unsigned int bits) { - int k, lim = bits/BITS_PER_LONG; + unsigned int k, lim = bits / BITS_PER_LONG; + for (k = 0; k < lim; ++k) if (bitmap1[k] & bitmap2[k]) return 1; @@ -174,7 +175,8 @@ EXPORT_SYMBOL(__bitmap_intersects); int __bitmap_subset(const unsigned long *bitmap1, const unsigned long *bitmap2, unsigned int bits) { - int k, lim = bits/BITS_PER_LONG; + unsigned int k, lim = bits / BITS_PER_LONG; + for (k = 0; k < lim; ++k) if (bitmap1[k] & ~bitmap2[k]) return 0; @@ -200,11 +202,11 @@ unsigned int __bitmap_weight(const unsigned long *bitmap, unsigned int bits) } EXPORT_SYMBOL(__bitmap_weight); -void __bitmap_set(unsigned long *map, unsigned int start, int len) +void __bitmap_set(unsigned long *bitmap, unsigned int start, unsigned int len) { - unsigned long *p = map + BIT_WORD(start); + unsigned long *p = bitmap + BIT_WORD(start); const unsigned int size = start + len; - int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG); + unsigned int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG); unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start); while (len - bits_to_set >= 0) { @@ -220,11 +222,11 @@ void __bitmap_set(unsigned long *map, unsigned int start, int len) } } -void __bitmap_clear(unsigned long *map, unsigned int start, int len) +void __bitmap_clear(unsigned long *bitmap, unsigned int start, unsigned int len) { - unsigned long *p = map + BIT_WORD(start); + unsigned long *p = bitmap + BIT_WORD(start); const unsigned int size = start + len; - int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG); + unsigned int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG); unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start); while (len - bits_to_clear >= 0) { @@ -255,11 +257,11 @@ void __bitmap_clear(unsigned long *map, unsigned int start, int len) * * Returns either beginning of region or negative error */ -int bitmap_find_free_region(unsigned long *bitmap, int bits, int order) +int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, unsigned int order) { unsigned long mask; - int pages = 1 << order; - int i; + unsigned int pages = 1 << order; + unsigned int i; if(pages > BITS_PER_LONG) return -EINVAL; @@ -270,8 +272,9 @@ int bitmap_find_free_region(unsigned long *bitmap, int bits, int order) /* run up the bitmap pages bits at a time */ for (i = 0; i < bits; i += pages) { - int index = i/BITS_PER_LONG; - int offset = i - (index * BITS_PER_LONG); + unsigned int index = i / BITS_PER_LONG; + unsigned int offset = i - (index * BITS_PER_LONG); + if((bitmap[index] & (mask << offset)) == 0) { /* set region in bimap */ bitmap[index] |= (mask << offset); @@ -291,23 +294,26 @@ EXPORT_SYMBOL(bitmap_find_free_region); * This is the complement to __bitmap_find_free_region and releases * the found region (by clearing it in the bitmap). */ -void bitmap_release_region(unsigned long *bitmap, int pos, int order) +void bitmap_release_region(unsigned long *bitmap, unsigned int pos, + unsigned int order) { - int pages = 1 << order; + unsigned int pages = 1 << order; unsigned long mask = (1ul << (pages - 1)); - int index = pos/BITS_PER_LONG; - int offset = pos - (index * BITS_PER_LONG); + unsigned int index = pos / BITS_PER_LONG; + unsigned int offset = pos - (index * BITS_PER_LONG); + mask += mask - 1; bitmap[index] &= ~(mask << offset); } EXPORT_SYMBOL(bitmap_release_region); -int bitmap_allocate_region(unsigned long *bitmap, int pos, int order) +int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, + unsigned int order) { - int pages = 1 << order; + unsigned int pages = 1 << order; unsigned long mask = (1ul << (pages - 1)); - int index = pos/BITS_PER_LONG; - int offset = pos - (index * BITS_PER_LONG); + unsigned int index = pos/BITS_PER_LONG; + unsigned int offset = pos - (index * BITS_PER_LONG); /* We don't do regions of pages > BITS_PER_LONG. The * algorithm would be a simple look for multiple zeros in the @@ -328,7 +334,7 @@ static void bitmap_long_to_byte(uint8_t *bp, const unsigned long *lp, unsigned int nbits) { unsigned long l; - int i, j, b; + unsigned int i, j, b; for (i = 0, b = 0; nbits > 0; i++, b += sizeof(l)) { l = lp[i]; @@ -345,7 +351,7 @@ static void bitmap_byte_to_long(unsigned long *lp, const uint8_t *bp, unsigned int nbits) { unsigned long l; - int i, j, b; + unsigned int i, j, b; for (i = 0, b = 0; nbits > 0; i++, b += sizeof(l)) { l = 0; diff --git a/xen/include/xen/bitmap.h b/xen/include/xen/bitmap.h index b9f980e91930..4e71b4350f59 100644 --- a/xen/include/xen/bitmap.h +++ b/xen/include/xen/bitmap.h @@ -85,12 +85,15 @@ int __bitmap_intersects(const unsigned long *bitmap1, int __bitmap_subset(const unsigned long *bitmap1, const unsigned long *bitmap2, unsigned int bits); unsigned int __bitmap_weight(const unsigned long *bitmap, unsigned int bits); -extern void __bitmap_set(unsigned long *map, unsigned int start, int len); -extern void __bitmap_clear(unsigned long *map, unsigned int start, int len); - -extern int bitmap_find_free_region(unsigned long *bitmap, int bits, int order); -extern void bitmap_release_region(unsigned long *bitmap, int pos, int order); -extern int bitmap_allocate_region(unsigned long *bitmap, int pos, int order); +void __bitmap_set(unsigned long *bitmap, unsigned int start, unsigned int len); +void __bitmap_clear(unsigned long *bitmap, unsigned int start, unsigned int len); + +int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, + unsigned int order); +void bitmap_release_region(unsigned long *bitmap, unsigned int pos, + unsigned int order); +int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, + unsigned int order); #define BITMAP_LAST_WORD_MASK(nbits) \ ( \ -- 2.30.2
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