Re: [PATCH v2 4/7] malloc: Decorate malloc maps

[DJ Delorie <dj@redhat.com>]

LGTM
Reviewed-by: DJ Delorie <dj@redhat.com>

Adhemerval Zanella <adhemerval.zanella@linaro.org> writes:
> Add anonymous mmap annotations on loader malloc, malloc when it
> allocates memory with mmap, and on malloc arena.  The /proc/self/maps
> will now print:
>
>    [anon: glibc: malloc arena]
>    [anon: glibc: malloc]
>    [anon: glibc: loader malloc]
>
> On arena allocation, glibc annotates only the read/write mapping.
>
> Checked on x86_64-linux-gnu and aarch64-linux-gnu.
> ---
>  elf/Makefile            |  4 ++++
>  elf/dl-minimal-malloc.c |  2 ++
>  elf/tst-decorate-maps.c | 37 +++++++++++++++++++++++++++++++++++++
>  malloc/arena.c          |  4 ++++
>  malloc/malloc.c         |  5 +++++
>  nptl/Makefile           |  4 ++++
>  6 files changed, 56 insertions(+)


> diff --git a/elf/Makefile b/elf/Makefile
> +
> +tst-decorate-maps-ENV = \
> +  GLIBC_TUNABLES=glibc.malloc.arena_max=8:glibc.malloc.mmap_threshold=1024
> +tst-decorate-maps-ARGS = 8

Ok.

> diff --git a/elf/dl-minimal-malloc.c b/elf/dl-minimal-malloc.c
> +#include <setvmaname.h>

Ok.

>  		     MAP_ANON|MAP_PRIVATE, -1, 0);
>        if (page == MAP_FAILED)
>  	return NULL;
> +      __set_vma_name (page, nup, " glibc: loader malloc");
>        if (page != alloc_end)
>  	alloc_ptr = page;
>        alloc_end = page + nup;

Ok.

> diff --git a/elf/tst-decorate-maps.c b/elf/tst-decorate-maps.c
>  
> +static int expected_n_arenas;
> +
>  static void *
>  tf (void *closure)
>  {
> +  void *p = xmalloc (1024);
> +
>    /* Wait the thread startup, so thread stack is allocated.  */
>    xpthread_barrier_wait (&b);
>  
>    /* Wait the test to read the process mapiping.  */
> +
>    xpthread_barrier_wait (&b);
>  
> +  free (p);
> +
>    return NULL;
>  }

Ok.  Enough to create an arena, not enough to mmap the chunk.

> @@ -48,6 +55,9 @@ struct proc_maps_t
>  {
>    int n_def_threads;
>    int n_user_threads;
> +  int n_arenas;
> +  int n_malloc_mmap;
> +  int n_loader_malloc_mmap;
>  };

Ok.

> @@ -69,6 +79,12 @@ read_proc_maps (void)
>  	r.n_def_threads++;
>        else if (strstr (line, "[anon: glibc: pthread user stack:") != NULL)
>  	r.n_user_threads++;
> +      else if (strstr (line, "[anon: glibc: malloc arena]") != NULL)
> +	r.n_arenas++;
> +      else if (strstr (line, "[anon: glibc: malloc]") != NULL)
> +	r.n_malloc_mmap++;
> +      else if (strstr (line, "[anon: glibc: loader malloc]") != NULL)
> +	r.n_loader_malloc_mmap++;
>      }
>    free (line);
>    xfclose (f);

Ok.

> @@ -90,6 +106,9 @@ do_test_threads (bool set_guard)
>  
>    xpthread_barrier_init (&b, NULL, num_threads + 1);
>  
> +  /* Issue a large malloc to trigger a mmap call.  */
> +  void *p = xmalloc (256 * 1024);
> +
>    pthread_t thr[num_threads];
>    {
>      int i = 0;

Ok.

> @@ -128,6 +147,10 @@ do_test_threads (bool set_guard)
>      struct proc_maps_t r = read_proc_maps ();
>      TEST_COMPARE (r.n_def_threads, num_def_threads);
>      TEST_COMPARE (r.n_user_threads, num_user_threads);
> +    TEST_COMPARE (r.n_arenas, expected_n_arenas);
> +    TEST_COMPARE (r.n_malloc_mmap, 1);
> +    /* On some architectures the loader might use more than one page.  */
> +    TEST_VERIFY (r.n_loader_malloc_mmap >= 1);
>    }

Ok.

>    /* Let the threads finish.  */
> @@ -140,8 +163,22 @@ do_test_threads (bool set_guard)
>      struct proc_maps_t r = read_proc_maps ();
>      TEST_COMPARE (r.n_def_threads, 0);
>      TEST_COMPARE (r.n_user_threads, 0);
> +    TEST_COMPARE (r.n_arenas, expected_n_arenas);
> +    TEST_COMPARE (r.n_malloc_mmap, 1);
> +    TEST_VERIFY (r.n_loader_malloc_mmap >= 1);
>    }
> +
> +  free (p);
> +}

Ok.

> +static void
> +do_prepare (int argc, char *argv[])
> +{
> +  TEST_VERIFY_EXIT (argc == 2);
> +  expected_n_arenas = strtol (argv[1], NULL, 10);
> +  expected_n_arenas = expected_n_arenas - 1;
>  }
> +#define PREPARE do_prepare

Ok.

> diff --git a/malloc/arena.c b/malloc/arena.c
> index 6f03955ff2..d1e214ac2e 100644
> --- a/malloc/arena.c
> +++ b/malloc/arena.c
> @@ -17,6 +17,7 @@
>     not, see <https://www.gnu.org/licenses/>.  */
>  
>  #include <stdbool.h>
> +#include <setvmaname.h>

Ok.

>  #define TUNABLE_NAMESPACE malloc
>  #include <elf/dl-tunables.h>
> @@ -436,6 +437,9 @@ alloc_new_heap  (size_t size, size_t top_pad, size_t pagesize,
>        return 0;
>      }
>  
> +  /* Only considere the actual usable range.  */
> +  __set_vma_name (p2, size, " glibc: malloc arena");
> +
>    madvise_thp (p2, size);
>  

Ok.

> diff --git a/malloc/malloc.c b/malloc/malloc.c
>  #include <sys/sysinfo.h>
>  
>  #include <ldsodefs.h>
> +#include <setvmaname.h>

Ok.

> @@ -2428,6 +2429,8 @@ sysmalloc_mmap (INTERNAL_SIZE_T nb, size_t pagesize, int extra_flags, mstate av)
>      madvise_thp (mm, size);
>  #endif
>  
> +  __set_vma_name (mm, size, " glibc: malloc");
> +

Ok.

> @@ -2513,6 +2516,8 @@ sysmalloc_mmap_fallback (long int *s, INTERNAL_SIZE_T nb,
>      madvise_thp (mbrk, size);
>  #endif
>  
> +  __set_vma_name (mbrk, size, " glibc: malloc");
> +

Ok.

> diff --git a/nptl/Makefile b/nptl/Makefile
> +tst-pthread-proc-maps-ENV = \
> +  GLIBC_TUNABLES=glibc.malloc.arena_max=8:glibc.malloc.mmap_threshold=1024
> +tst-pthread-proc-maps-ARGS = 8
> +

Ok.