libbpf's hashmap use of __WORDSIZE

libbpf's hashmap use of __WORDSIZE

[Arnaldo Carvalho de Melo]

Hi Andrii,

	We've got that hashmap.[ch] copy from libbpf so that we can
build perf in systems where libbpf isn't available, and to make it build
in all the containers I regularly test build perf I had to add the patch
below, I test build with many versions of both gcc and clang and
multiple libcs.

  https://gcc.gnu.org/onlinedocs/cpp/Common-Predefined-Macros.html

The way that tools/include/linux/bitops.h has been doing since 2012 is
explained in:

  http://git.kernel.org/torvalds/c/3f34f6c0233ae055b5

Please take a look and see if you find it acceptable,

Thanks,

- Arnaldo
  
  Warning: Kernel ABI header at 'tools/perf/util/hashmap.h' differs from latest version at 'tools/lib/bpf/hashmap.h'
  diff -u tools/perf/util/hashmap.h tools/lib/bpf/hashmap.h

$ diff -u tools/lib/bpf/hashmap.h tools/perf/util/hashmap.h
--- tools/lib/bpf/hashmap.h	2020-06-05 13:25:27.822079838 -0300
+++ tools/perf/util/hashmap.h	2020-06-05 13:25:27.838079794 -0300
@@ -10,10 +10,9 @@
 
 #include <stdbool.h>
 #include <stddef.h>
-#ifdef __GLIBC__
-#include <bits/wordsize.h>
-#else
-#include <bits/reg.h>
+#include <limits.h>
+#ifndef __WORDSIZE
+#define __WORDSIZE (__SIZEOF_LONG__ * 8)
 #endif
 
 static inline size_t hash_bits(size_t h, int bits)

Re: libbpf's hashmap use of __WORDSIZE

[Andrii Nakryiko]

On Mon, Jun 8, 2020 at 9:11 AM Arnaldo Carvalho de Melo
<arnaldo.melo@gmail.com> wrote:
>
> Hi Andrii,
>
>         We've got that hashmap.[ch] copy from libbpf so that we can
> build perf in systems where libbpf isn't available, and to make it build
> in all the containers I regularly test build perf I had to add the patch
> below, I test build with many versions of both gcc and clang and
> multiple libcs.
>
>   https://gcc.gnu.org/onlinedocs/cpp/Common-Predefined-Macros.html
>
> The way that tools/include/linux/bitops.h has been doing since 2012 is
> explained in:
>
>   http://git.kernel.org/torvalds/c/3f34f6c0233ae055b5
>
> Please take a look and see if you find it acceptable,
>
> Thanks,
>
> - Arnaldo
>
>   Warning: Kernel ABI header at 'tools/perf/util/hashmap.h' differs from latest version at 'tools/lib/bpf/hashmap.h'
>   diff -u tools/perf/util/hashmap.h tools/lib/bpf/hashmap.h
>
> $ diff -u tools/lib/bpf/hashmap.h tools/perf/util/hashmap.h
> --- tools/lib/bpf/hashmap.h     2020-06-05 13:25:27.822079838 -0300
> +++ tools/perf/util/hashmap.h   2020-06-05 13:25:27.838079794 -0300
> @@ -10,10 +10,9 @@
>
>  #include <stdbool.h>
>  #include <stddef.h>
> -#ifdef __GLIBC__
> -#include <bits/wordsize.h>
> -#else
> -#include <bits/reg.h>
> +#include <limits.h>
> +#ifndef __WORDSIZE
> +#define __WORDSIZE (__SIZEOF_LONG__ * 8)
>  #endif

This looks fine, I also build-tested it in Travis CI, so all good.
There is actually __SIZEOF_SIZE_T__, which is more directly what
hash_bits work with, but I don't think it matters for any reasonable
system in use :)

So yeah,

Acked-by: Andrii Nakryiko <andriin@fb.com>

Are you going to do this change for libbpf's variant, or should I
submit a separate patch?

>
>  static inline size_t hash_bits(size_t h, int bits)

Re: libbpf's hashmap use of __WORDSIZE

[Arnaldo Carvalho de Melo]

Mi

On June 8, 2020 2:32:16 PM GMT-03:00, Andrii Nakryiko <andrii.nakryiko@gmail.com> wrote:
>On Mon, Jun 8, 2020 at 9:11 AM Arnaldo Carvalho de Melo
><arnaldo.melo@gmail.com> wrote:
>>
>> Hi Andrii,
>>
>>         We've got that hashmap.[ch] copy from libbpf so that we can
>> build perf in systems where libbpf isn't available, and to make it
>build
>> in all the containers I regularly test build perf I had to add the
>patch
>> below, I test build with many versions of both gcc and clang and
>> multiple libcs.
>>
>>   https://gcc.gnu.org/onlinedocs/cpp/Common-Predefined-Macros.html
>>
>> The way that tools/include/linux/bitops.h has been doing since 2012
>is
>> explained in:
>>
>>   http://git.kernel.org/torvalds/c/3f34f6c0233ae055b5
>>
>> Please take a look and see if you find it acceptable,
>>
>> Thanks,
>>
>> - Arnaldo
>>
>>   Warning: Kernel ABI header at 'tools/perf/util/hashmap.h' differs
>from latest version at 'tools/lib/bpf/hashmap.h'
>>   diff -u tools/perf/util/hashmap.h tools/lib/bpf/hashmap.h
>>
>> $ diff -u tools/lib/bpf/hashmap.h tools/perf/util/hashmap.h
>> --- tools/lib/bpf/hashmap.h     2020-06-05 13:25:27.822079838 -0300
>> +++ tools/perf/util/hashmap.h   2020-06-05 13:25:27.838079794 -0300
>> @@ -10,10 +10,9 @@
>>
>>  #include <stdbool.h>
>>  #include <stddef.h>
>> -#ifdef __GLIBC__
>> -#include <bits/wordsize.h>
>> -#else
>> -#include <bits/reg.h>
>> +#include <limits.h>
>> +#ifndef __WORDSIZE
>> +#define __WORDSIZE (__SIZEOF_LONG__ * 8)
>>  #endif
>
>This looks fine, I also build-tested it in Travis CI, so all good.
>There is actually __SIZEOF_SIZE_T__, which is more directly what
>hash_bits work with, but I don't think it matters for any reasonable
>system in use :)
>
>So yeah,
>
>Acked-by: Andrii Nakryiko <andriin@fb.com>
>
>Are you going to do this change for libbpf's variant, or should I
>submit a separate patch?

I'll send the patch later,

Thanks for checking,

- Arnaldo
>
>>
>>  static inline size_t hash_bits(size_t h, int bits)

-- 
Sent from my Android device with K-9 Mail. Please excuse my brevity.

[PATCH] libbpf: Define __WORDSIZE if not available

[Arnaldo Carvalho de Melo]

Some systems, such as Android, don't have a define for __WORDSIZE, do it
in terms of __SIZEOF_LONG__, as done in perf since 2012:

  http://git.kernel.org/torvalds/c/3f34f6c0233ae055b5

For reference: https://gcc.gnu.org/onlinedocs/cpp/Common-Predefined-Macros.html

I build tested it here and Andrii did some Travis CI build tests too.

Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Re: [PATCH] libbpf: Define __WORDSIZE if not available

[Daniel Borkmann]

Hey Arnaldo,

On 6/9/20 5:34 PM, Arnaldo Carvalho de Melo wrote:
> Some systems, such as Android, don't have a define for __WORDSIZE, do it
> in terms of __SIZEOF_LONG__, as done in perf since 2012:
> 
>    http://git.kernel.org/torvalds/c/3f34f6c0233ae055b5
> 
> For reference: https://gcc.gnu.org/onlinedocs/cpp/Common-Predefined-Macros.html
> 
> I build tested it here and Andrii did some Travis CI build tests too.
> 
> Acked-by: Andrii Nakryiko <andriin@fb.com>
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Diff missing?

Thanks,
Daniel

Re: [PATCH] libbpf: Define __WORDSIZE if not available

[Arnaldo Carvalho de Melo]

Em Tue, Jun 09, 2020 at 10:37:48PM +0200, Daniel Borkmann escreveu:
> Hey Arnaldo,
> 
> On 6/9/20 5:34 PM, Arnaldo Carvalho de Melo wrote:
> > Some systems, such as Android, don't have a define for __WORDSIZE, do it
> > in terms of __SIZEOF_LONG__, as done in perf since 2012:
> > 
> >    http://git.kernel.org/torvalds/c/3f34f6c0233ae055b5
> > 
> > For reference: https://gcc.gnu.org/onlinedocs/cpp/Common-Predefined-Macros.html
> > 
> > I build tested it here and Andrii did some Travis CI build tests too.
> > 
> > Acked-by: Andrii Nakryiko <andriin@fb.com>
> > Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> 
> Diff missing?

Oh well, sorry about that, EBADCOFFEE or something:

From: Arnaldo Carvalho de Melo <acme@kernel.org>

Some systems, such as Android, don't have a define for __WORDSIZE, do it
in terms of __SIZEOF_LONG__, as done in perf since 2012:

   http://git.kernel.org/torvalds/c/3f34f6c0233ae055b5

For reference: https://gcc.gnu.org/onlinedocs/cpp/Common-Predefined-Macros.html

I build tested it here and Andrii did some Travis CI build tests too.

Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

---

diff --git a/tools/lib/bpf/hashmap.h b/tools/lib/bpf/hashmap.h
index e823b35e7371..df59fd4fc95b 100644
--- a/tools/lib/bpf/hashmap.h
+++ b/tools/lib/bpf/hashmap.h
@@ -10,10 +10,9 @@
 
 #include <stdbool.h>
 #include <stddef.h>
-#ifdef __GLIBC__
-#include <bits/wordsize.h>
-#else
-#include <bits/reg.h>
+#include <limits.h>
+#ifndef __WORDSIZE
+#define __WORDSIZE (__SIZEOF_LONG__ * 8)
 #endif
 
 static inline size_t hash_bits(size_t h, int bits)

Re: [PATCH] libbpf: Define __WORDSIZE if not available

[Daniel Borkmann]

On 6/9/20 11:16 PM, Arnaldo Carvalho de Melo wrote:
> Em Tue, Jun 09, 2020 at 10:37:48PM +0200, Daniel Borkmann escreveu:
>> Hey Arnaldo,
>>
>> On 6/9/20 5:34 PM, Arnaldo Carvalho de Melo wrote:
>>> Some systems, such as Android, don't have a define for __WORDSIZE, do it
>>> in terms of __SIZEOF_LONG__, as done in perf since 2012:
>>>
>>>     http://git.kernel.org/torvalds/c/3f34f6c0233ae055b5
>>>
>>> For reference: https://gcc.gnu.org/onlinedocs/cpp/Common-Predefined-Macros.html
>>>
>>> I build tested it here and Andrii did some Travis CI build tests too.
>>>
>>> Acked-by: Andrii Nakryiko <andriin@fb.com>
>>> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
>>
>> Diff missing?
> 
> Oh well, sorry about that, EBADCOFFEE or something:
> 
> From: Arnaldo Carvalho de Melo <acme@kernel.org>
> 
> Some systems, such as Android, don't have a define for __WORDSIZE, do it
> in terms of __SIZEOF_LONG__, as done in perf since 2012:
> 
>     http://git.kernel.org/torvalds/c/3f34f6c0233ae055b5
> 
> For reference: https://gcc.gnu.org/onlinedocs/cpp/Common-Predefined-Macros.html
> 
> I build tested it here and Andrii did some Travis CI build tests too.
> 
> Acked-by: Andrii Nakryiko <andriin@fb.com>
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> 
[...]

Applied, thanks!