* [PATCH v2] lib: optimize cpumask_next_and()
@ 2017-10-24 10:51 Clement Courbet
2017-10-25 7:28 ` Matthew Wilcox
` (3 more replies)
0 siblings, 4 replies; 13+ messages in thread
From: Clement Courbet @ 2017-10-24 10:51 UTC (permalink / raw)
To: Arnd Bergmann, Rasmus Villemoes, Andrew Morton, Matthew Wilcox,
Yury Norov
Cc: Clement Courbet, Ingo Molnar, linux-arch, linux-kernel
We've measured that we spend ~0.6% of sys cpu time in cpumask_next_and().
It's essentially a joined iteration in search for a non-zero bit, which
is currently implemented as a lookup join (find a nonzero bit on the
lhs, lookup the rhs to see if it's set there).
Implement a direct join (find a nonzero bit on the incrementally built
join). Direct benchmarking shows that it's 1.17x to 14x faster with a
geometric mean of 2.1 on 32 CPUs. No impact on memory usage.
Approximate benchmark code:
```
unsigned long src1p[nr_cpumask_longs] = {pattern1};
unsigned long src2p[nr_cpumask_longs] = {pattern2};
for (/*a bunch of repetitions*/) {
for (int n = -1; n <= nr_cpu_ids; ++n) {
asm volatile("" : "+rm"(src1p)); // prevent any optimization
asm volatile("" : "+rm"(src2p));
unsigned long result = cpumask_next_and(n, src1p, src2p);
asm volatile("" : "+rm"(result));
}
}
```
Results:
pattern1 pattern2 time_before/time_after
0x0000ffff 0x0000ffff 1.65
0x0000ffff 0x00005555 2.24
0x0000ffff 0x00001111 2.94
0x0000ffff 0x00000000 14.0
0x00005555 0x0000ffff 1.67
0x00005555 0x00005555 1.71
0x00005555 0x00001111 1.90
0x00005555 0x00000000 6.58
0x00001111 0x0000ffff 1.46
0x00001111 0x00005555 1.49
0x00001111 0x00001111 1.45
0x00001111 0x00000000 3.10
0x00000000 0x0000ffff 1.18
0x00000000 0x00005555 1.18
0x00000000 0x00001111 1.17
0x00000000 0x00000000 1.25
-----------------------------
geo.mean 2.06
Signed-off-by: Clement Courbet <courbet@google.com>
---
Changes in v2:
- Refactored _find_next_common_bit into _find_next_bit., as suggested
by Yury Norov. This has no adverse effects on the performance side,
as the compiler successfully inlines the code.
include/asm-generic/bitops/find.h | 16 ++++++++++++++
include/linux/bitmap.h | 2 ++
lib/cpumask.c | 9 ++++----
lib/find_bit.c | 37 +++++++++++++++++++++++++--------
tools/include/asm-generic/bitops/find.h | 16 ++++++++++++++
5 files changed, 67 insertions(+), 13 deletions(-)
diff --git a/include/asm-generic/bitops/find.h b/include/asm-generic/bitops/find.h
index 998d4d544f18..130962f3a264 100644
--- a/include/asm-generic/bitops/find.h
+++ b/include/asm-generic/bitops/find.h
@@ -15,6 +15,22 @@ extern unsigned long find_next_bit(const unsigned long *addr, unsigned long
size, unsigned long offset);
#endif
+#ifndef find_next_and_bit
+/**
+ * find_next_and_bit - find the next set bit in both memory regions
+ * @addr1: The first address to base the search on
+ * @addr2: The second address to base the search on
+ * @offset: The bitnumber to start searching at
+ * @size: The bitmap size in bits
+ *
+ * Returns the bit number for the next set bit
+ * If no bits are set, returns @size.
+ */
+extern unsigned long find_next_and_bit(const unsigned long *addr1,
+ const unsigned long *addr2, unsigned long size,
+ unsigned long offset);
+#endif
+
#ifndef find_next_zero_bit
/**
* find_next_zero_bit - find the next cleared bit in a memory region
diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
index 700cf5f67118..b4606bfda52f 100644
--- a/include/linux/bitmap.h
+++ b/include/linux/bitmap.h
@@ -77,6 +77,8 @@
* 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
+ * find_next_and_bit(addr1, addr2, nbits, bit) Same as find_first_bit, but in
+ * (*addr1 & *addr2)
*/
/*
diff --git a/lib/cpumask.c b/lib/cpumask.c
index 8b1a1bd77539..5602223837fa 100644
--- a/lib/cpumask.c
+++ b/lib/cpumask.c
@@ -32,10 +32,11 @@ EXPORT_SYMBOL(cpumask_next);
int cpumask_next_and(int n, const struct cpumask *src1p,
const struct cpumask *src2p)
{
- while ((n = cpumask_next(n, src1p)) < nr_cpu_ids)
- if (cpumask_test_cpu(n, src2p))
- break;
- return n;
+ /* -1 is a legal arg here. */
+ if (n != -1)
+ cpumask_check(n);
+ return find_next_and_bit(cpumask_bits(src1p), cpumask_bits(src2p),
+ nr_cpumask_bits, n + 1);
}
EXPORT_SYMBOL(cpumask_next_and);
diff --git a/lib/find_bit.c b/lib/find_bit.c
index 6ed74f78380c..ebc08fd9fdf8 100644
--- a/lib/find_bit.c
+++ b/lib/find_bit.c
@@ -24,19 +24,25 @@
#if !defined(find_next_bit) || !defined(find_next_zero_bit)
/*
- * This is a common helper function for find_next_bit and
- * find_next_zero_bit. The difference is the "invert" argument, which
- * is XORed with each fetched word before searching it for one bits.
+ * This is a common helper function for find_next_bit, find_next_zero_bit, and
+ * find_next_and_bit. The differences are:
+ * - The "invert" argument, which is XORed with each fetched word before
+ * searching it for one bits.
+ * - The optional "addr2", which is anded with "addr1" if present.
*/
-static unsigned long _find_next_bit(const unsigned long *addr,
- unsigned long nbits, unsigned long start, unsigned long invert)
+static unsigned long _find_next_bit(const unsigned long *addr1,
+ const unsigned long *addr2, unsigned long nbits,
+ unsigned long start, unsigned long invert)
{
unsigned long tmp;
if (unlikely(start >= nbits))
return nbits;
- tmp = addr[start / BITS_PER_LONG] ^ invert;
+ tmp = addr1[start / BITS_PER_LONG];
+ if (addr2)
+ tmp &= addr2[start / BITS_PER_LONG];
+ tmp ^= invert;
/* Handle 1st word. */
tmp &= BITMAP_FIRST_WORD_MASK(start);
@@ -47,7 +53,10 @@ static unsigned long _find_next_bit(const unsigned long *addr,
if (start >= nbits)
return nbits;
- tmp = addr[start / BITS_PER_LONG] ^ invert;
+ tmp = addr1[start / BITS_PER_LONG];
+ if (addr2)
+ tmp &= addr2[start / BITS_PER_LONG];
+ tmp ^= invert;
}
return min(start + __ffs(tmp), nbits);
@@ -61,7 +70,7 @@ static unsigned long _find_next_bit(const unsigned long *addr,
unsigned long find_next_bit(const unsigned long *addr, unsigned long size,
unsigned long offset)
{
- return _find_next_bit(addr, size, offset, 0UL);
+ return _find_next_bit(addr, NULL, size, offset, 0UL);
}
EXPORT_SYMBOL(find_next_bit);
#endif
@@ -70,11 +79,21 @@ EXPORT_SYMBOL(find_next_bit);
unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size,
unsigned long offset)
{
- return _find_next_bit(addr, size, offset, ~0UL);
+ return _find_next_bit(addr, NULL, size, offset, ~0UL);
}
EXPORT_SYMBOL(find_next_zero_bit);
#endif
+#if !defined(find_next_and_bit)
+unsigned long find_next_and_bit(const unsigned long *addr1,
+ const unsigned long *addr2, unsigned long nbits,
+ unsigned long start)
+{
+ return _find_next_bit(addr1, addr2, size, offset, ~0UL);
+}
+EXPORT_SYMBOL(find_next_and_bit);
+#endif
+
#ifndef find_first_bit
/*
* Find the first set bit in a memory region.
diff --git a/tools/include/asm-generic/bitops/find.h b/tools/include/asm-generic/bitops/find.h
index 5538ecdc964a..435c7d002f33 100644
--- a/tools/include/asm-generic/bitops/find.h
+++ b/tools/include/asm-generic/bitops/find.h
@@ -15,6 +15,22 @@ extern unsigned long find_next_bit(const unsigned long *addr, unsigned long
size, unsigned long offset);
#endif
+#ifndef find_next_and_bit
+/**
+ * find_next_and_bit - find the next set bit in both memory regions
+ * @addr1: The first address to base the search on
+ * @addr2: The second address to base the search on
+ * @offset: The bitnumber to start searching at
+ * @size: The bitmap size in bits
+ *
+ * Returns the bit number for the next set bit
+ * If no bits are set, returns @size.
+ */
+extern unsigned long find_next_and_bit(const unsigned long *addr1,
+ const unsigned long *addr2, unsigned long size,
+ unsigned long offset);
+#endif
+
#ifndef find_next_zero_bit
/**
--
2.15.0.rc0.271.g36b669edcc-goog
^ permalink raw reply related [flat|nested] 13+ messages in thread
* RE: [PATCH v2] lib: optimize cpumask_next_and()
2017-10-24 10:51 [PATCH v2] lib: optimize cpumask_next_and() Clement Courbet
@ 2017-10-25 7:28 ` Matthew Wilcox
2017-10-25 14:59 ` Yury Norov
` (2 subsequent siblings)
3 siblings, 0 replies; 13+ messages in thread
From: Matthew Wilcox @ 2017-10-25 7:28 UTC (permalink / raw)
To: Clement Courbet, Arnd Bergmann, Rasmus Villemoes, Andrew Morton,
Yury Norov
Cc: Ingo Molnar, linux-arch, linux-kernel
Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com>
> -----Original Message-----
> From: Clement Courbet [mailto:courbet@google.com]
> Sent: Tuesday, October 24, 2017 6:52 AM
> To: Arnd Bergmann <arnd@arndb.de>; Rasmus Villemoes
> <linux@rasmusvillemoes.dk>; Andrew Morton <akpm@linux-foundation.org>;
> Matthew Wilcox <mawilcox@microsoft.com>; Yury Norov
> <ynorov@caviumnetworks.com>
> Cc: Clement Courbet <courbet@google.com>; Ingo Molnar
> <mingo@kernel.org>; linux-arch@vger.kernel.org; linux-kernel@vger.kernel.org
> Subject: [PATCH v2] lib: optimize cpumask_next_and()
>
> We've measured that we spend ~0.6% of sys cpu time in cpumask_next_and().
> It's essentially a joined iteration in search for a non-zero bit, which
> is currently implemented as a lookup join (find a nonzero bit on the
> lhs, lookup the rhs to see if it's set there).
>
> Implement a direct join (find a nonzero bit on the incrementally built
> join). Direct benchmarking shows that it's 1.17x to 14x faster with a
> geometric mean of 2.1 on 32 CPUs. No impact on memory usage.
>
> Approximate benchmark code:
>
> ```
> unsigned long src1p[nr_cpumask_longs] = {pattern1};
> unsigned long src2p[nr_cpumask_longs] = {pattern2};
> for (/*a bunch of repetitions*/) {
> for (int n = -1; n <= nr_cpu_ids; ++n) {
> asm volatile("" : "+rm"(src1p)); // prevent any optimization
> asm volatile("" : "+rm"(src2p));
> unsigned long result = cpumask_next_and(n, src1p, src2p);
> asm volatile("" : "+rm"(result));
> }
> }
> ```
>
> Results:
> pattern1 pattern2 time_before/time_after
> 0x0000ffff 0x0000ffff 1.65
> 0x0000ffff 0x00005555 2.24
> 0x0000ffff 0x00001111 2.94
> 0x0000ffff 0x00000000 14.0
> 0x00005555 0x0000ffff 1.67
> 0x00005555 0x00005555 1.71
> 0x00005555 0x00001111 1.90
> 0x00005555 0x00000000 6.58
> 0x00001111 0x0000ffff 1.46
> 0x00001111 0x00005555 1.49
> 0x00001111 0x00001111 1.45
> 0x00001111 0x00000000 3.10
> 0x00000000 0x0000ffff 1.18
> 0x00000000 0x00005555 1.18
> 0x00000000 0x00001111 1.17
> 0x00000000 0x00000000 1.25
> -----------------------------
> geo.mean 2.06
>
> Signed-off-by: Clement Courbet <courbet@google.com>
> ---
> Changes in v2:
> - Refactored _find_next_common_bit into _find_next_bit., as suggested
> by Yury Norov. This has no adverse effects on the performance side,
> as the compiler successfully inlines the code.
>
> include/asm-generic/bitops/find.h | 16 ++++++++++++++
> include/linux/bitmap.h | 2 ++
> lib/cpumask.c | 9 ++++----
> lib/find_bit.c | 37 +++++++++++++++++++++++++--------
> tools/include/asm-generic/bitops/find.h | 16 ++++++++++++++
> 5 files changed, 67 insertions(+), 13 deletions(-)
>
> diff --git a/include/asm-generic/bitops/find.h b/include/asm-
> generic/bitops/find.h
> index 998d4d544f18..130962f3a264 100644
> --- a/include/asm-generic/bitops/find.h
> +++ b/include/asm-generic/bitops/find.h
> @@ -15,6 +15,22 @@ extern unsigned long find_next_bit(const unsigned long
> *addr, unsigned long
> size, unsigned long offset);
> #endif
>
> +#ifndef find_next_and_bit
> +/**
> + * find_next_and_bit - find the next set bit in both memory regions
> + * @addr1: The first address to base the search on
> + * @addr2: The second address to base the search on
> + * @offset: The bitnumber to start searching at
> + * @size: The bitmap size in bits
> + *
> + * Returns the bit number for the next set bit
> + * If no bits are set, returns @size.
> + */
> +extern unsigned long find_next_and_bit(const unsigned long *addr1,
> + const unsigned long *addr2, unsigned long size,
> + unsigned long offset);
> +#endif
> +
> #ifndef find_next_zero_bit
> /**
> * find_next_zero_bit - find the next cleared bit in a memory region
> diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
> index 700cf5f67118..b4606bfda52f 100644
> --- a/include/linux/bitmap.h
> +++ b/include/linux/bitmap.h
> @@ -77,6 +77,8 @@
> * 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
> + * find_next_and_bit(addr1, addr2, nbits, bit) Same as find_first_bit, but in
> + * (*addr1 & *addr2)
> */
>
> /*
> diff --git a/lib/cpumask.c b/lib/cpumask.c
> index 8b1a1bd77539..5602223837fa 100644
> --- a/lib/cpumask.c
> +++ b/lib/cpumask.c
> @@ -32,10 +32,11 @@ EXPORT_SYMBOL(cpumask_next);
> int cpumask_next_and(int n, const struct cpumask *src1p,
> const struct cpumask *src2p)
> {
> - while ((n = cpumask_next(n, src1p)) < nr_cpu_ids)
> - if (cpumask_test_cpu(n, src2p))
> - break;
> - return n;
> + /* -1 is a legal arg here. */
> + if (n != -1)
> + cpumask_check(n);
> + return find_next_and_bit(cpumask_bits(src1p), cpumask_bits(src2p),
> + nr_cpumask_bits, n + 1);
> }
> EXPORT_SYMBOL(cpumask_next_and);
>
> diff --git a/lib/find_bit.c b/lib/find_bit.c
> index 6ed74f78380c..ebc08fd9fdf8 100644
> --- a/lib/find_bit.c
> +++ b/lib/find_bit.c
> @@ -24,19 +24,25 @@
> #if !defined(find_next_bit) || !defined(find_next_zero_bit)
>
> /*
> - * This is a common helper function for find_next_bit and
> - * find_next_zero_bit. The difference is the "invert" argument, which
> - * is XORed with each fetched word before searching it for one bits.
> + * This is a common helper function for find_next_bit, find_next_zero_bit, and
> + * find_next_and_bit. The differences are:
> + * - The "invert" argument, which is XORed with each fetched word before
> + * searching it for one bits.
> + * - The optional "addr2", which is anded with "addr1" if present.
> */
> -static unsigned long _find_next_bit(const unsigned long *addr,
> - unsigned long nbits, unsigned long start, unsigned long invert)
> +static unsigned long _find_next_bit(const unsigned long *addr1,
> + const unsigned long *addr2, unsigned long nbits,
> + unsigned long start, unsigned long invert)
> {
> unsigned long tmp;
>
> if (unlikely(start >= nbits))
> return nbits;
>
> - tmp = addr[start / BITS_PER_LONG] ^ invert;
> + tmp = addr1[start / BITS_PER_LONG];
> + if (addr2)
> + tmp &= addr2[start / BITS_PER_LONG];
> + tmp ^= invert;
>
> /* Handle 1st word. */
> tmp &= BITMAP_FIRST_WORD_MASK(start);
> @@ -47,7 +53,10 @@ static unsigned long _find_next_bit(const unsigned long
> *addr,
> if (start >= nbits)
> return nbits;
>
> - tmp = addr[start / BITS_PER_LONG] ^ invert;
> + tmp = addr1[start / BITS_PER_LONG];
> + if (addr2)
> + tmp &= addr2[start / BITS_PER_LONG];
> + tmp ^= invert;
> }
>
> return min(start + __ffs(tmp), nbits);
> @@ -61,7 +70,7 @@ static unsigned long _find_next_bit(const unsigned long
> *addr,
> unsigned long find_next_bit(const unsigned long *addr, unsigned long size,
> unsigned long offset)
> {
> - return _find_next_bit(addr, size, offset, 0UL);
> + return _find_next_bit(addr, NULL, size, offset, 0UL);
> }
> EXPORT_SYMBOL(find_next_bit);
> #endif
> @@ -70,11 +79,21 @@ EXPORT_SYMBOL(find_next_bit);
> unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long
> size,
> unsigned long offset)
> {
> - return _find_next_bit(addr, size, offset, ~0UL);
> + return _find_next_bit(addr, NULL, size, offset, ~0UL);
> }
> EXPORT_SYMBOL(find_next_zero_bit);
> #endif
>
> +#if !defined(find_next_and_bit)
> +unsigned long find_next_and_bit(const unsigned long *addr1,
> + const unsigned long *addr2, unsigned long nbits,
> + unsigned long start)
> +{
> + return _find_next_bit(addr1, addr2, size, offset, ~0UL);
> +}
> +EXPORT_SYMBOL(find_next_and_bit);
> +#endif
> +
> #ifndef find_first_bit
> /*
> * Find the first set bit in a memory region.
> diff --git a/tools/include/asm-generic/bitops/find.h b/tools/include/asm-
> generic/bitops/find.h
> index 5538ecdc964a..435c7d002f33 100644
> --- a/tools/include/asm-generic/bitops/find.h
> +++ b/tools/include/asm-generic/bitops/find.h
> @@ -15,6 +15,22 @@ extern unsigned long find_next_bit(const unsigned long
> *addr, unsigned long
> size, unsigned long offset);
> #endif
>
> +#ifndef find_next_and_bit
> +/**
> + * find_next_and_bit - find the next set bit in both memory regions
> + * @addr1: The first address to base the search on
> + * @addr2: The second address to base the search on
> + * @offset: The bitnumber to start searching at
> + * @size: The bitmap size in bits
> + *
> + * Returns the bit number for the next set bit
> + * If no bits are set, returns @size.
> + */
> +extern unsigned long find_next_and_bit(const unsigned long *addr1,
> + const unsigned long *addr2, unsigned long size,
> + unsigned long offset);
> +#endif
> +
> #ifndef find_next_zero_bit
>
> /**
> --
> 2.15.0.rc0.271.g36b669edcc-goog
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH v2] lib: optimize cpumask_next_and()
2017-10-24 10:51 [PATCH v2] lib: optimize cpumask_next_and() Clement Courbet
2017-10-25 7:28 ` Matthew Wilcox
@ 2017-10-25 14:59 ` Yury Norov
2017-10-25 15:28 ` Re " Clement Courbet
2017-10-26 12:12 ` kbuild test robot
2017-10-26 12:22 ` kbuild test robot
3 siblings, 1 reply; 13+ messages in thread
From: Yury Norov @ 2017-10-25 14:59 UTC (permalink / raw)
To: Clement Courbet
Cc: Arnd Bergmann, Rasmus Villemoes, Andrew Morton, Matthew Wilcox,
Ingo Molnar, linux-arch, linux-kernel
On Tue, Oct 24, 2017 at 12:51:59PM +0200, Clement Courbet wrote:
> We've measured that we spend ~0.6% of sys cpu time in cpumask_next_and().
> It's essentially a joined iteration in search for a non-zero bit, which
> is currently implemented as a lookup join (find a nonzero bit on the
> lhs, lookup the rhs to see if it's set there).
>
> Implement a direct join (find a nonzero bit on the incrementally built
> join). Direct benchmarking shows that it's 1.17x to 14x faster with a
> geometric mean of 2.1 on 32 CPUs. No impact on memory usage.
>
> Approximate benchmark code:
>
> ```
> unsigned long src1p[nr_cpumask_longs] = {pattern1};
> unsigned long src2p[nr_cpumask_longs] = {pattern2};
> for (/*a bunch of repetitions*/) {
> for (int n = -1; n <= nr_cpu_ids; ++n) {
> asm volatile("" : "+rm"(src1p)); // prevent any optimization
> asm volatile("" : "+rm"(src2p));
> unsigned long result = cpumask_next_and(n, src1p, src2p);
> asm volatile("" : "+rm"(result));
> }
> }
> ```
> Signed-off-by: Clement Courbet <courbet@google.com>
> ---
> Changes in v2:
> - Refactored _find_next_common_bit into _find_next_bit., as suggested
> by Yury Norov.
What I actually suggested is make _find_next_and_bit() similar to
_find_next_bit(), not to extend _find_next_bit(). But what you did
looks OK.
> This has no adverse effects on the performance side,
> as the compiler successfully inlines the code.
I think it's not about inlining, compiler just optimizes out branches known
as false at compile-time.
> include/asm-generic/bitops/find.h | 16 ++++++++++++++
> include/linux/bitmap.h | 2 ++
> lib/cpumask.c | 9 ++++----
> lib/find_bit.c | 37 +++++++++++++++++++++++++--------
> tools/include/asm-generic/bitops/find.h | 16 ++++++++++++++
> 5 files changed, 67 insertions(+), 13 deletions(-)
>
> diff --git a/include/asm-generic/bitops/find.h b/include/asm-generic/bitops/find.h
> index 998d4d544f18..130962f3a264 100644
> --- a/include/asm-generic/bitops/find.h
> +++ b/include/asm-generic/bitops/find.h
> @@ -15,6 +15,22 @@ extern unsigned long find_next_bit(const unsigned long *addr, unsigned long
> size, unsigned long offset);
> #endif
>
> +#ifndef find_next_and_bit
> +/**
> + * find_next_and_bit - find the next set bit in both memory regions
> + * @addr1: The first address to base the search on
> + * @addr2: The second address to base the search on
> + * @offset: The bitnumber to start searching at
> + * @size: The bitmap size in bits
> + *
> + * Returns the bit number for the next set bit
> + * If no bits are set, returns @size.
> + */
> +extern unsigned long find_next_and_bit(const unsigned long *addr1,
> + const unsigned long *addr2, unsigned long size,
> + unsigned long offset);
> +#endif
> +
> #ifndef find_next_zero_bit
> /**
> * find_next_zero_bit - find the next cleared bit in a memory region
> diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
> index 700cf5f67118..b4606bfda52f 100644
> --- a/include/linux/bitmap.h
> +++ b/include/linux/bitmap.h
> @@ -77,6 +77,8 @@
> * 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
> + * find_next_and_bit(addr1, addr2, nbits, bit) Same as find_first_bit, but in
> + * (*addr1 & *addr2)
> */
>
> /*
> diff --git a/lib/cpumask.c b/lib/cpumask.c
> index 8b1a1bd77539..5602223837fa 100644
> --- a/lib/cpumask.c
> +++ b/lib/cpumask.c
> @@ -32,10 +32,11 @@ EXPORT_SYMBOL(cpumask_next);
> int cpumask_next_and(int n, const struct cpumask *src1p,
> const struct cpumask *src2p)
> {
> - while ((n = cpumask_next(n, src1p)) < nr_cpu_ids)
> - if (cpumask_test_cpu(n, src2p))
> - break;
> - return n;
> + /* -1 is a legal arg here. */
> + if (n != -1)
> + cpumask_check(n);
> + return find_next_and_bit(cpumask_bits(src1p), cpumask_bits(src2p),
> + nr_cpumask_bits, n + 1);
> }
> EXPORT_SYMBOL(cpumask_next_and);
>
> diff --git a/lib/find_bit.c b/lib/find_bit.c
> index 6ed74f78380c..ebc08fd9fdf8 100644
> --- a/lib/find_bit.c
> +++ b/lib/find_bit.c
> @@ -24,19 +24,25 @@
> #if !defined(find_next_bit) || !defined(find_next_zero_bit)
>
> /*
> - * This is a common helper function for find_next_bit and
> - * find_next_zero_bit. The difference is the "invert" argument, which
> - * is XORed with each fetched word before searching it for one bits.
> + * This is a common helper function for find_next_bit, find_next_zero_bit, and
> + * find_next_and_bit. The differences are:
> + * - The "invert" argument, which is XORed with each fetched word before
> + * searching it for one bits.
> + * - The optional "addr2", which is anded with "addr1" if present.
> */
> -static unsigned long _find_next_bit(const unsigned long *addr,
> - unsigned long nbits, unsigned long start, unsigned long invert)
> +static unsigned long _find_next_bit(const unsigned long *addr1,
> + const unsigned long *addr2, unsigned long nbits,
> + unsigned long start, unsigned long invert)
> {
> unsigned long tmp;
>
> if (unlikely(start >= nbits))
> return nbits;
>
> - tmp = addr[start / BITS_PER_LONG] ^ invert;
> + tmp = addr1[start / BITS_PER_LONG];
> + if (addr2)
> + tmp &= addr2[start / BITS_PER_LONG];
> + tmp ^= invert;
>
> /* Handle 1st word. */
> tmp &= BITMAP_FIRST_WORD_MASK(start);
> @@ -47,7 +53,10 @@ static unsigned long _find_next_bit(const unsigned long *addr,
> if (start >= nbits)
> return nbits;
>
> - tmp = addr[start / BITS_PER_LONG] ^ invert;
> + tmp = addr1[start / BITS_PER_LONG];
> + if (addr2)
> + tmp &= addr2[start / BITS_PER_LONG];
> + tmp ^= invert;
> }
>
> return min(start + __ffs(tmp), nbits);
> @@ -61,7 +70,7 @@ static unsigned long _find_next_bit(const unsigned long *addr,
> unsigned long find_next_bit(const unsigned long *addr, unsigned long size,
> unsigned long offset)
> {
> - return _find_next_bit(addr, size, offset, 0UL);
> + return _find_next_bit(addr, NULL, size, offset, 0UL);
> }
> EXPORT_SYMBOL(find_next_bit);
> #endif
> @@ -70,11 +79,21 @@ EXPORT_SYMBOL(find_next_bit);
> unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size,
> unsigned long offset)
> {
> - return _find_next_bit(addr, size, offset, ~0UL);
> + return _find_next_bit(addr, NULL, size, offset, ~0UL);
> }
> EXPORT_SYMBOL(find_next_zero_bit);
> #endif
>
> +#if !defined(find_next_and_bit)
> +unsigned long find_next_and_bit(const unsigned long *addr1,
> + const unsigned long *addr2, unsigned long nbits,
> + unsigned long start)
It should be:
unsigned long find_next_and_bit(const unsigned long *addr1,
const unsigned long *addr2, unsigned long size,
unsigned long offset)
> +{
> + return _find_next_bit(addr1, addr2, size, offset, ~0UL);
> +}
> +EXPORT_SYMBOL(find_next_and_bit);
> +#endif
> +
> #ifndef find_first_bit
> /*
> * Find the first set bit in a memory region.
If we continue this way, we'll most probably end up like this,
sooner or later:
diff --git a/lib/find_bit.c b/lib/find_bit.c
index ebc08fd9fdf8..1b0b4aedc93a 100644
--- a/lib/find_bit.c
+++ b/lib/find_bit.c
@@ -31,8 +31,12 @@
* - The optional "addr2", which is anded with "addr1" if present.
*/
static unsigned long _find_next_bit(const unsigned long *addr1,
- const unsigned long *addr2, unsigned long nbits,
- unsigned long start, unsigned long invert)
+ const unsigned long *and,
+ const unsigned long *or,
+ const unsigned long *xor,
+ unsigned long nbits,
+ unsigned long start,
+ unsigned long invert)
{
unsigned long tmp;
@@ -40,8 +44,12 @@ static unsigned long _find_next_bit(const unsigned long *addr1,
return nbits;
tmp = addr1[start / BITS_PER_LONG];
- if (addr2)
- tmp &= addr2[start / BITS_PER_LONG];
+ if (and)
+ tmp &= and[start / BITS_PER_LONG];
+ if (or)
+ tmp |= or[start / BITS_PER_LONG];
+ if (xor)
+ tmp ^= xor[start / BITS_PER_LONG];
tmp ^= invert;
/* Handle 1st word. */
@@ -54,8 +62,12 @@ static unsigned long _find_next_bit(const unsigned long *addr1,
return nbits;
tmp = addr1[start / BITS_PER_LONG];
- if (addr2)
- tmp &= addr2[start / BITS_PER_LONG];
+ if (and)
+ tmp &= and[start / BITS_PER_LONG];
+ if (or)
+ tmp |= or[start / BITS_PER_LONG];
+ if (xor)
+ tmp ^= xor[start / BITS_PER_LONG];
tmp ^= invert;
}
Just a fantasy of course.
I'm generally fine to proceed this way. It makes _find_next_bit() more
complex, but lets us avoid code duplication, which is better deal for
long-term maintenance.
But I'd like also to keep _find_next_bit() consistent with _find_next_bit_le()
Could you please send v3 with fixed find_next_and_bit() declaration,
and synced LE routines?
Yury
^ permalink raw reply related [flat|nested] 13+ messages in thread
* Re [PATCH v2] lib: optimize cpumask_next_and()
2017-10-25 14:59 ` Yury Norov
@ 2017-10-25 15:28 ` Clement Courbet
2017-10-25 15:50 ` Yury Norov
0 siblings, 1 reply; 13+ messages in thread
From: Clement Courbet @ 2017-10-25 15:28 UTC (permalink / raw)
To: Arnd Bergmann, Rasmus Villemoes, Andrew Morton, Matthew Wilcox,
Yury Norov
Cc: Clement Courbet, Ingo Molnar, linux-arch, linux-kernel
Thanks for the comments Yury.
> But I'd like also to keep _find_next_bit() consistent with
> _find_next_bit_le()
Not sure I understand what you're suggesting here: Do you want a
find_next_and_bit_le() or do you want to make _find_next_bit_le() more
like _find_next_bit() ? In the latter case we might just want to merge
it with _find_next_bit() and end up with an extra is_le parameter :)
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: Re [PATCH v2] lib: optimize cpumask_next_and()
2017-10-25 15:28 ` Re " Clement Courbet
@ 2017-10-25 15:50 ` Yury Norov
2017-10-25 17:41 ` Yury Norov
0 siblings, 1 reply; 13+ messages in thread
From: Yury Norov @ 2017-10-25 15:50 UTC (permalink / raw)
To: Clement Courbet
Cc: Arnd Bergmann, Rasmus Villemoes, Andrew Morton, Matthew Wilcox,
Ingo Molnar, linux-arch, linux-kernel
On Wed, Oct 25, 2017 at 05:28:41PM +0200, Clement Courbet wrote:
> Thanks for the comments Yury.
>
> > But I'd like also to keep _find_next_bit() consistent with
> > _find_next_bit_le()
>
> Not sure I understand what you're suggesting here: Do you want a
> find_next_and_bit_le() or do you want to make _find_next_bit_le() more
> like _find_next_bit() ? In the latter case we might just want to merge
> it with _find_next_bit() and end up with an extra is_le parameter :)
Both ways will work, but I think that extra is_le is too much.
_find_next_bit_le() should be the copy of _find_next_bit() with the
addition of swapping code.
If you don't need find_next_and_bit_le(), don't add it.
find_{first,last}_bit() doesn't have LE version, for example.
Yury
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: Re [PATCH v2] lib: optimize cpumask_next_and()
2017-10-25 15:50 ` Yury Norov
@ 2017-10-25 17:41 ` Yury Norov
0 siblings, 0 replies; 13+ messages in thread
From: Yury Norov @ 2017-10-25 17:41 UTC (permalink / raw)
To: Clement Courbet
Cc: Arnd Bergmann, Rasmus Villemoes, Andrew Morton, Matthew Wilcox,
Ingo Molnar, linux-arch, linux-kernel
On Wed, Oct 25, 2017 at 06:50:14PM +0300, Yury Norov wrote:
> On Wed, Oct 25, 2017 at 05:28:41PM +0200, Clement Courbet wrote:
> > Thanks for the comments Yury.
> >
> > > But I'd like also to keep _find_next_bit() consistent with
> > > _find_next_bit_le()
> >
> > Not sure I understand what you're suggesting here: Do you want a
> > find_next_and_bit_le() or do you want to make _find_next_bit_le() more
> > like _find_next_bit() ? In the latter case we might just want to merge
> > it with _find_next_bit() and end up with an extra is_le parameter :)
>
> Both ways will work, but I think that extra is_le is too much.
> _find_next_bit_le() should be the copy of _find_next_bit() with the
> addition of swapping code.
>
> If you don't need find_next_and_bit_le(), don't add it.
> find_{first,last}_bit() doesn't have LE version, for example.
Few comments more.
_find_next_bit is now referenced also by find_next_and_bit(), and
so it should be added to guard code:
#if !defined(find_next_bit) || !defined(find_next_zero_bit)
|| !defined(find_next_and_bit)
static unsigned long _find_next_bit( ... )
{
...
}
#endif
It may be essential at least for arm.
Don't forget to synchronize your changes with
tools/lib/find_bit.c
Thanks,
Yury
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH v2] lib: optimize cpumask_next_and()
2017-10-24 10:51 [PATCH v2] lib: optimize cpumask_next_and() Clement Courbet
2017-10-25 7:28 ` Matthew Wilcox
@ 2017-10-26 12:12 ` kbuild test robot
2017-10-26 12:12 ` kbuild test robot
2017-10-26 12:22 ` kbuild test robot
3 siblings, 0 replies; 13+ messages in thread
From: kbuild test robot @ 2017-10-26 12:12 UTC (permalink / raw)
To: Clement Courbet
Cc: kbuild-all, Arnd Bergmann, Rasmus Villemoes, Andrew Morton,
Matthew Wilcox, Yury Norov, Clement Courbet, Ingo Molnar,
linux-arch, linux-kernel
[-- Attachment #1: Type: text/plain, Size: 1751 bytes --]
Hi Clement,
[auto build test ERROR on linus/master]
[also build test ERROR on v4.14-rc6 next-20171018]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Clement-Courbet/lib-optimize-cpumask_next_and/20171026-184850
config: i386-randconfig-x001-201743 (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
# save the attached .config to linux build tree
make ARCH=i386
All error/warnings (new ones prefixed by >>):
lib/find_bit.c: In function 'find_next_and_bit':
>> lib/find_bit.c:92:38: error: 'size' undeclared (first use in this function)
return _find_next_bit(addr1, addr2, size, offset, ~0UL);
^~~~
lib/find_bit.c:92:38: note: each undeclared identifier is reported only once for each function it appears in
>> lib/find_bit.c:92:44: error: 'offset' undeclared (first use in this function)
return _find_next_bit(addr1, addr2, size, offset, ~0UL);
^~~~~~
>> lib/find_bit.c:93:1: warning: control reaches end of non-void function [-Wreturn-type]
}
^
vim +/size +92 lib/find_bit.c
86
87 #if !defined(find_next_and_bit)
88 unsigned long find_next_and_bit(const unsigned long *addr1,
89 const unsigned long *addr2, unsigned long nbits,
90 unsigned long start)
91 {
> 92 return _find_next_bit(addr1, addr2, size, offset, ~0UL);
> 93 }
94 EXPORT_SYMBOL(find_next_and_bit);
95 #endif
96
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 26064 bytes --]
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH v2] lib: optimize cpumask_next_and()
@ 2017-10-26 12:12 ` kbuild test robot
0 siblings, 0 replies; 13+ messages in thread
From: kbuild test robot @ 2017-10-26 12:12 UTC (permalink / raw)
Cc: kbuild-all, Arnd Bergmann, Rasmus Villemoes, Andrew Morton,
Matthew Wilcox, Yury Norov, Clement Courbet, Ingo Molnar,
linux-arch, linux-kernel
[-- Attachment #1: Type: text/plain, Size: 1751 bytes --]
Hi Clement,
[auto build test ERROR on linus/master]
[also build test ERROR on v4.14-rc6 next-20171018]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Clement-Courbet/lib-optimize-cpumask_next_and/20171026-184850
config: i386-randconfig-x001-201743 (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
# save the attached .config to linux build tree
make ARCH=i386
All error/warnings (new ones prefixed by >>):
lib/find_bit.c: In function 'find_next_and_bit':
>> lib/find_bit.c:92:38: error: 'size' undeclared (first use in this function)
return _find_next_bit(addr1, addr2, size, offset, ~0UL);
^~~~
lib/find_bit.c:92:38: note: each undeclared identifier is reported only once for each function it appears in
>> lib/find_bit.c:92:44: error: 'offset' undeclared (first use in this function)
return _find_next_bit(addr1, addr2, size, offset, ~0UL);
^~~~~~
>> lib/find_bit.c:93:1: warning: control reaches end of non-void function [-Wreturn-type]
}
^
vim +/size +92 lib/find_bit.c
86
87 #if !defined(find_next_and_bit)
88 unsigned long find_next_and_bit(const unsigned long *addr1,
89 const unsigned long *addr2, unsigned long nbits,
90 unsigned long start)
91 {
> 92 return _find_next_bit(addr1, addr2, size, offset, ~0UL);
> 93 }
94 EXPORT_SYMBOL(find_next_and_bit);
95 #endif
96
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 26064 bytes --]
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH v2] lib: optimize cpumask_next_and()
@ 2017-10-26 12:12 ` kbuild test robot
0 siblings, 0 replies; 13+ messages in thread
From: kbuild test robot @ 2017-10-26 12:12 UTC (permalink / raw)
To: Clement Courbet
Cc: kbuild-all, Arnd Bergmann, Rasmus Villemoes, Andrew Morton,
Matthew Wilcox, Yury Norov, Ingo Molnar, linux-arch,
linux-kernel
[-- Attachment #1: Type: text/plain, Size: 1751 bytes --]
Hi Clement,
[auto build test ERROR on linus/master]
[also build test ERROR on v4.14-rc6 next-20171018]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Clement-Courbet/lib-optimize-cpumask_next_and/20171026-184850
config: i386-randconfig-x001-201743 (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
# save the attached .config to linux build tree
make ARCH=i386
All error/warnings (new ones prefixed by >>):
lib/find_bit.c: In function 'find_next_and_bit':
>> lib/find_bit.c:92:38: error: 'size' undeclared (first use in this function)
return _find_next_bit(addr1, addr2, size, offset, ~0UL);
^~~~
lib/find_bit.c:92:38: note: each undeclared identifier is reported only once for each function it appears in
>> lib/find_bit.c:92:44: error: 'offset' undeclared (first use in this function)
return _find_next_bit(addr1, addr2, size, offset, ~0UL);
^~~~~~
>> lib/find_bit.c:93:1: warning: control reaches end of non-void function [-Wreturn-type]
}
^
vim +/size +92 lib/find_bit.c
86
87 #if !defined(find_next_and_bit)
88 unsigned long find_next_and_bit(const unsigned long *addr1,
89 const unsigned long *addr2, unsigned long nbits,
90 unsigned long start)
91 {
> 92 return _find_next_bit(addr1, addr2, size, offset, ~0UL);
> 93 }
94 EXPORT_SYMBOL(find_next_and_bit);
95 #endif
96
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 26064 bytes --]
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH v2] lib: optimize cpumask_next_and()
2017-10-24 10:51 [PATCH v2] lib: optimize cpumask_next_and() Clement Courbet
2017-10-25 7:28 ` Matthew Wilcox
@ 2017-10-26 12:22 ` kbuild test robot
2017-10-26 12:12 ` kbuild test robot
2017-10-26 12:22 ` kbuild test robot
3 siblings, 0 replies; 13+ messages in thread
From: kbuild test robot @ 2017-10-26 12:22 UTC (permalink / raw)
To: Clement Courbet
Cc: kbuild-all, Arnd Bergmann, Rasmus Villemoes, Andrew Morton,
Matthew Wilcox, Yury Norov, Clement Courbet, Ingo Molnar,
linux-arch, linux-kernel
[-- Attachment #1: Type: text/plain, Size: 2106 bytes --]
Hi Clement,
[auto build test ERROR on linus/master]
[also build test ERROR on v4.14-rc6 next-20171018]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Clement-Courbet/lib-optimize-cpumask_next_and/20171026-184850
config: m68k-allyesconfig (attached as .config)
compiler: m68k-linux-gcc (GCC) 4.9.0
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
make.cross ARCH=m68k
All errors (new ones prefixed by >>):
lib/find_bit.c: In function 'find_next_and_bit':
>> lib/find_bit.c:92:2: error: implicit declaration of function '_find_next_bit' [-Werror=implicit-function-declaration]
return _find_next_bit(addr1, addr2, size, offset, ~0UL);
^
lib/find_bit.c:92:38: error: 'size' undeclared (first use in this function)
return _find_next_bit(addr1, addr2, size, offset, ~0UL);
^
lib/find_bit.c:92:38: note: each undeclared identifier is reported only once for each function it appears in
lib/find_bit.c:92:44: error: 'offset' undeclared (first use in this function)
return _find_next_bit(addr1, addr2, size, offset, ~0UL);
^
lib/find_bit.c:93:1: warning: control reaches end of non-void function [-Wreturn-type]
}
^
cc1: some warnings being treated as errors
vim +/_find_next_bit +92 lib/find_bit.c
86
87 #if !defined(find_next_and_bit)
88 unsigned long find_next_and_bit(const unsigned long *addr1,
89 const unsigned long *addr2, unsigned long nbits,
90 unsigned long start)
91 {
> 92 return _find_next_bit(addr1, addr2, size, offset, ~0UL);
93 }
94 EXPORT_SYMBOL(find_next_and_bit);
95 #endif
96
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 44325 bytes --]
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH v2] lib: optimize cpumask_next_and()
@ 2017-10-26 12:22 ` kbuild test robot
0 siblings, 0 replies; 13+ messages in thread
From: kbuild test robot @ 2017-10-26 12:22 UTC (permalink / raw)
Cc: kbuild-all, Arnd Bergmann, Rasmus Villemoes, Andrew Morton,
Matthew Wilcox, Yury Norov, Clement Courbet, Ingo Molnar,
linux-arch, linux-kernel
[-- Attachment #1: Type: text/plain, Size: 2106 bytes --]
Hi Clement,
[auto build test ERROR on linus/master]
[also build test ERROR on v4.14-rc6 next-20171018]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Clement-Courbet/lib-optimize-cpumask_next_and/20171026-184850
config: m68k-allyesconfig (attached as .config)
compiler: m68k-linux-gcc (GCC) 4.9.0
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
make.cross ARCH=m68k
All errors (new ones prefixed by >>):
lib/find_bit.c: In function 'find_next_and_bit':
>> lib/find_bit.c:92:2: error: implicit declaration of function '_find_next_bit' [-Werror=implicit-function-declaration]
return _find_next_bit(addr1, addr2, size, offset, ~0UL);
^
lib/find_bit.c:92:38: error: 'size' undeclared (first use in this function)
return _find_next_bit(addr1, addr2, size, offset, ~0UL);
^
lib/find_bit.c:92:38: note: each undeclared identifier is reported only once for each function it appears in
lib/find_bit.c:92:44: error: 'offset' undeclared (first use in this function)
return _find_next_bit(addr1, addr2, size, offset, ~0UL);
^
lib/find_bit.c:93:1: warning: control reaches end of non-void function [-Wreturn-type]
}
^
cc1: some warnings being treated as errors
vim +/_find_next_bit +92 lib/find_bit.c
86
87 #if !defined(find_next_and_bit)
88 unsigned long find_next_and_bit(const unsigned long *addr1,
89 const unsigned long *addr2, unsigned long nbits,
90 unsigned long start)
91 {
> 92 return _find_next_bit(addr1, addr2, size, offset, ~0UL);
93 }
94 EXPORT_SYMBOL(find_next_and_bit);
95 #endif
96
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 44325 bytes --]
^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [PATCH v2] lib: optimize cpumask_next_and()
@ 2017-10-26 12:22 ` kbuild test robot
0 siblings, 0 replies; 13+ messages in thread
From: kbuild test robot @ 2017-10-26 12:22 UTC (permalink / raw)
To: Clement Courbet
Cc: kbuild-all, Arnd Bergmann, Rasmus Villemoes, Andrew Morton,
Matthew Wilcox, Yury Norov, Ingo Molnar, linux-arch,
linux-kernel
[-- Attachment #1: Type: text/plain, Size: 2106 bytes --]
Hi Clement,
[auto build test ERROR on linus/master]
[also build test ERROR on v4.14-rc6 next-20171018]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Clement-Courbet/lib-optimize-cpumask_next_and/20171026-184850
config: m68k-allyesconfig (attached as .config)
compiler: m68k-linux-gcc (GCC) 4.9.0
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
make.cross ARCH=m68k
All errors (new ones prefixed by >>):
lib/find_bit.c: In function 'find_next_and_bit':
>> lib/find_bit.c:92:2: error: implicit declaration of function '_find_next_bit' [-Werror=implicit-function-declaration]
return _find_next_bit(addr1, addr2, size, offset, ~0UL);
^
lib/find_bit.c:92:38: error: 'size' undeclared (first use in this function)
return _find_next_bit(addr1, addr2, size, offset, ~0UL);
^
lib/find_bit.c:92:38: note: each undeclared identifier is reported only once for each function it appears in
lib/find_bit.c:92:44: error: 'offset' undeclared (first use in this function)
return _find_next_bit(addr1, addr2, size, offset, ~0UL);
^
lib/find_bit.c:93:1: warning: control reaches end of non-void function [-Wreturn-type]
}
^
cc1: some warnings being treated as errors
vim +/_find_next_bit +92 lib/find_bit.c
86
87 #if !defined(find_next_and_bit)
88 unsigned long find_next_and_bit(const unsigned long *addr1,
89 const unsigned long *addr2, unsigned long nbits,
90 unsigned long start)
91 {
> 92 return _find_next_bit(addr1, addr2, size, offset, ~0UL);
93 }
94 EXPORT_SYMBOL(find_next_and_bit);
95 #endif
96
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 44325 bytes --]
^ permalink raw reply [flat|nested] 13+ messages in thread
* [PATCH v2] lib: optimize cpumask_next_and()
2017-10-26 12:58 [PATCH v3] " Alexey Dobriyan
@ 2017-10-26 15:52 ` Clement Courbet
0 siblings, 0 replies; 13+ messages in thread
From: Clement Courbet @ 2017-10-26 15:52 UTC (permalink / raw)
To: Arnd Bergmann, Rasmus Villemoes, Andrew Morton, Matthew Wilcox,
Yury Norov
Cc: Clement Courbet, Ingo Molnar, linux-arch, linux-kernel
Hi Alexey,
> Gentoo ships 5.4.0 which doesn't inline this code on x86_64 defconfig
> (which has OPTIMIZE_INLINING).
I have not actually marked _find_next_bit() inline, it just turns out
that my compiler inlines it.
I've tried out marking the function inline and OPTIMIZE_INLINING does
not un-inline it. I'll send a v4 with an explicit inine.
^ permalink raw reply [flat|nested] 13+ messages in thread
end of thread, other threads:[~2017-10-26 15:52 UTC | newest]
Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-10-24 10:51 [PATCH v2] lib: optimize cpumask_next_and() Clement Courbet
2017-10-25 7:28 ` Matthew Wilcox
2017-10-25 14:59 ` Yury Norov
2017-10-25 15:28 ` Re " Clement Courbet
2017-10-25 15:50 ` Yury Norov
2017-10-25 17:41 ` Yury Norov
2017-10-26 12:12 ` kbuild test robot
2017-10-26 12:12 ` kbuild test robot
2017-10-26 12:12 ` kbuild test robot
2017-10-26 12:22 ` kbuild test robot
2017-10-26 12:22 ` kbuild test robot
2017-10-26 12:22 ` kbuild test robot
2017-10-26 12:58 [PATCH v3] " Alexey Dobriyan
2017-10-26 15:52 ` [PATCH v2] " Clement Courbet
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.