Re: [PATCH 1/3 (fix commit message)] perf tools: Recognize hugetlb mapping as anon mapping

[Wangnan (F)]

On 2016/9/6 3:18, Arnaldo Carvalho de Melo wrote:
> Em Sun, Sep 04, 2016 at 05:04:38AM +0000, Wang Nan escreveu:
> > Hugetlbfs mapping should be recognized as anon mapping so user has
> > a chance to create /tmp/perf-<pid>.map file for symbol resolving. This
> > patch utilizes MAP_HUGETLB to identify hugetlb mapping.
> >
> > After this patch, if perf is started before the program starts using
> > huge pages (so perf gets MMAP2 events from kernel), perf is able to
> > recognize hugetlb mapping as anon mapping.
> Fixing build on older distros (Centos5, Ubuntu 12.04.5, etc)
>
>
>    CC       /tmp/build/perf/arch/x86/util/perf_regs.o
> util/event.c: In function 'perf_event__synthesize_mmap_events':
> util/event.c:350: error: 'MAP_HUGETLB' undeclared (first use in this function)
> util/event.c:350: error: (Each undeclared identifier is reported only once
> util/event.c:350: error: for each function it appears in.)
>
>   

Fixing MAP_HUGETLB is not as easy as it seems to be. Its value
is different in each arch:

./arch/powerpc/include/uapi/asm/mman.h:#define MAP_HUGETLB 0x40000    
    /* create a huge page mapping */
./arch/alpha/include/uapi/asm/mman.h:#define MAP_HUGETLB 0x100000    /* 
create a huge page mapping */
./arch/xtensa/include/uapi/asm/mman.h:#define MAP_HUGETLB 0x80000        
/* create a huge page mapping */
./arch/tile/include/uapi/asm/mman.h:#define MAP_HUGETLB    0x4000     /* 
create a huge page mapping */
./arch/parisc/include/uapi/asm/mman.h:#define MAP_HUGETLB 0x80000        
/* create a huge page mapping */
./arch/sparc/include/uapi/asm/mman.h:#define MAP_HUGETLB 0x40000        
/* create a huge page mapping */
./arch/mips/include/uapi/asm/mman.h:#define MAP_HUGETLB 0x80000        
/* create a huge page mapping */
./include/uapi/asm-generic/mman.h:#define MAP_HUGETLB    0x40000     /* 
create a huge page mapping */

So we need to introduce another header into tools for this macro. Sigh...

Thank you.

> > Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
> > Signed-off-by: Hou Pengyang <houpengyang@xxxxxxxxxx>
> > Cc: He Kuang <hekuang@xxxxxxxxxx>
> > Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> > Cc: Nilay Vaish <nilayvaish@xxxxxxxxx>
> > ---
> >   tools/perf/util/map.c | 8 +++++---
> >   1 file changed, 5 insertions(+), 3 deletions(-)
> >
> > diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
> > index 728129a..a42010d 100644
> > --- a/tools/perf/util/map.c
> > +++ b/tools/perf/util/map.c
> > @@ -6,6 +6,7 @@
> >   #include <string.h>
> >   #include <stdio.h>
> >   #include <unistd.h>
> > +#include <sys/mman.h>
> >   #include "map.h"
> >   #include "thread.h"
> >   #include "strlist.h"
> > @@ -24,9 +25,10 @@ const char *map_type__name[MAP__NR_TYPES] = {
> >   	[MAP__VARIABLE] = "Variables",
> >   };
> >   
> > -static inline int is_anon_memory(const char *filename)
> > +static inline int is_anon_memory(const char *filename, u32 flags)
> >   {
> > -	return !strcmp(filename, "//anon") ||
> > +	return flags & MAP_HUGETLB ||
> > +	       !strcmp(filename, "//anon") ||
> >   	       !strncmp(filename, "/dev/zero", sizeof("/dev/zero") - 1) ||
> >   	       !strncmp(filename, "/anon_hugepage", sizeof("/anon_hugepage") - 1);
> >   }
> > @@ -155,7 +157,7 @@ struct map *map__new(struct machine *machine, u64 start, u64 len,
> >   		int anon, no_dso, vdso, android;
> >   
> >   		android = is_android_lib(filename);
> > -		anon = is_anon_memory(filename);
> > +		anon = is_anon_memory(filename, flags);
> >   		vdso = is_vdso_map(filename);
> >   		no_dso = is_no_dso_memory(filename);
> >   
> > --
> > 1.8.3.4