[PATCH v3] malloc: Use C11 atomics on memusage

[PATCH v3] malloc: Use C11 atomics on memusage

[Adhemerval Zanella]

Checked on x86_64-linux-gnu.

Changes from previous version:
- Use stdatomic instead of glibc internal atomics and use relaxed MO
  instead of acquire.

---
 malloc/memusage.c | 193 ++++++++++++++++++++++++++--------------------
 1 file changed, 111 insertions(+), 82 deletions(-)

diff --git a/malloc/memusage.c b/malloc/memusage.c
index 6d71047154..2a3a508557 100644
--- a/malloc/memusage.c
+++ b/malloc/memusage.c
@@ -17,21 +17,16 @@
    <https://www.gnu.org/licenses/>.  */
 
 #include <assert.h>
-#include <atomic.h>
 #include <dlfcn.h>
-#include <errno.h>
 #include <fcntl.h>
-#include <inttypes.h>
-#include <signal.h>
-#include <stdarg.h>
+#include <stdatomic.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
-#include <unistd.h>
-#include <stdint.h>
+#include <stdarg.h>
 #include <sys/mman.h>
 #include <sys/time.h>
+#include <unistd.h>
 
 #include <hp-timing.h>
 #include <machine-sp.h>
@@ -73,20 +68,20 @@ struct header
 #define MAGIC 0xfeedbeaf
 
 
-static unsigned long int calls[idx_last];
-static unsigned long int failed[idx_last];
-static size_t total[idx_last];
-static size_t grand_total;
-static unsigned long int histogram[65536 / 16];
-static unsigned long int large;
-static unsigned long int calls_total;
-static unsigned long int inplace;
-static unsigned long int decreasing;
-static unsigned long int realloc_free;
-static unsigned long int inplace_mremap;
-static unsigned long int decreasing_mremap;
-static size_t current_heap;
-static size_t peak_use[3];
+static _Atomic unsigned long int calls[idx_last];
+static _Atomic unsigned long int failed[idx_last];
+static _Atomic size_t total[idx_last];
+static _Atomic size_t grand_total;
+static _Atomic unsigned long int histogram[65536 / 16];
+static _Atomic unsigned long int large;
+static _Atomic unsigned long int calls_total;
+static _Atomic unsigned long int inplace;
+static _Atomic unsigned long int decreasing;
+static _Atomic unsigned long int realloc_free;
+static _Atomic unsigned long int inplace_mremap;
+static _Atomic unsigned long int decreasing_mremap;
+static _Atomic size_t current_heap;
+static _Atomic size_t peak_use[3];
 static __thread uintptr_t start_sp;
 
 /* A few macros to make the source more readable.  */
@@ -113,7 +108,7 @@ struct entry
 };
 
 static struct entry buffer[2 * DEFAULT_BUFFER_SIZE];
-static uint32_t buffer_cnt;
+static _Atomic uint32_t buffer_cnt;
 static struct entry first;
 
 static void
@@ -134,6 +129,19 @@ gettime (struct entry *e)
 #endif
 }
 
+static inline void
+peak_atomic_max (_Atomic size_t *peak, size_t val)
+{
+  size_t v;
+  do
+    {
+      v = atomic_load_explicit (peak, memory_order_relaxed);
+      if (v >= val)
+	break;
+    }
+  while (! atomic_compare_exchange_weak (peak, &v, val));
+}
+
 /* Update the global data after a successful function call.  */
 static void
 update_data (struct header *result, size_t len, size_t old_len)
@@ -148,8 +156,9 @@ update_data (struct header *result, size_t len, size_t old_len)
 
   /* Compute current heap usage and compare it with the maximum value.  */
   size_t heap
-    = catomic_exchange_and_add (&current_heap, len - old_len) + len - old_len;
-  catomic_max (&peak_heap, heap);
+    = atomic_fetch_add_explicit (&current_heap, len - old_len,
+				 memory_order_relaxed) + len - old_len;
+  peak_atomic_max (&peak_heap, heap);
 
   /* Compute current stack usage and compare it with the maximum
      value.  The base stack pointer might not be set if this is not
@@ -172,15 +181,16 @@ update_data (struct header *result, size_t len, size_t old_len)
     start_sp = sp;
   size_t current_stack = start_sp - sp;
 #endif
-  catomic_max (&peak_stack, current_stack);
+  peak_atomic_max (&peak_stack, current_stack);
 
   /* Add up heap and stack usage and compare it with the maximum value.  */
-  catomic_max (&peak_total, heap + current_stack);
+  peak_atomic_max (&peak_total, heap + current_stack);
 
   /* Store the value only if we are writing to a file.  */
   if (fd != -1)
     {
-      uint32_t idx = catomic_exchange_and_add (&buffer_cnt, 1);
+      uint32_t idx = atomic_fetch_add_explicit (&buffer_cnt, 1,
+						memory_order_relaxed);
       if (idx + 1 >= 2 * buffer_size)
         {
           /* We try to reset the counter to the correct range.  If
@@ -188,7 +198,8 @@ update_data (struct header *result, size_t len, size_t old_len)
              counter it does not matter since that thread will take
              care of the correction.  */
           uint32_t reset = (idx + 1) % (2 * buffer_size);
-          catomic_compare_and_exchange_val_acq (&buffer_cnt, reset, idx + 1);
+	  uint32_t expected = idx + 1;
+	  atomic_compare_exchange_weak (&buffer_cnt, &expected, reset);
           if (idx >= 2 * buffer_size)
             idx = reset - 1;
         }
@@ -362,24 +373,25 @@ malloc (size_t len)
     return (*mallocp)(len);
 
   /* Keep track of number of calls.  */
-  catomic_increment (&calls[idx_malloc]);
+  atomic_fetch_add_explicit (&calls[idx_malloc], 1, memory_order_relaxed);
   /* Keep track of total memory consumption for `malloc'.  */
-  catomic_add (&total[idx_malloc], len);
+  atomic_fetch_add_explicit (&total[idx_malloc], len, memory_order_relaxed);
   /* Keep track of total memory requirement.  */
-  catomic_add (&grand_total, len);
+  atomic_fetch_add_explicit (&grand_total, len, memory_order_relaxed);
   /* Remember the size of the request.  */
   if (len < 65536)
-    catomic_increment (&histogram[len / 16]);
+    atomic_fetch_add_explicit (&histogram[len / 16], 1, memory_order_relaxed);
   else
-    catomic_increment (&large);
+    atomic_fetch_add_explicit (&large, 1, memory_order_relaxed);
   /* Total number of calls of any of the functions.  */
-  catomic_increment (&calls_total);
+  atomic_fetch_add_explicit (&calls_total, 1, memory_order_relaxed);
 
   /* Do the real work.  */
   result = (struct header *) (*mallocp)(len + sizeof (struct header));
   if (result == NULL)
     {
-      catomic_increment (&failed[idx_malloc]);
+      atomic_fetch_add_explicit (&failed[idx_malloc], 1,
+				 memory_order_relaxed);
       return NULL;
     }
 
@@ -430,21 +442,24 @@ realloc (void *old, size_t len)
     }
 
   /* Keep track of number of calls.  */
-  catomic_increment (&calls[idx_realloc]);
+  atomic_fetch_add_explicit (&calls[idx_realloc], 1, memory_order_relaxed);
   if (len > old_len)
     {
       /* Keep track of total memory consumption for `realloc'.  */
-      catomic_add (&total[idx_realloc], len - old_len);
+      atomic_fetch_add_explicit (&total[idx_realloc], len - old_len,
+				 memory_order_relaxed);
       /* Keep track of total memory requirement.  */
-      catomic_add (&grand_total, len - old_len);
+      atomic_fetch_add_explicit (&grand_total, len - old_len,
+				 memory_order_relaxed);
     }
 
   if (len == 0 && old != NULL)
     {
       /* Special case.  */
-      catomic_increment (&realloc_free);
+      atomic_fetch_add_explicit (&realloc_free, 1, memory_order_relaxed);
       /* Keep track of total memory freed using `free'.  */
-      catomic_add (&total[idx_free], real->length);
+      atomic_fetch_add_explicit (&total[idx_free], real->length,
+				 memory_order_relaxed);
 
       /* Update the allocation data and write out the records if necessary.  */
       update_data (NULL, 0, old_len);
@@ -457,26 +472,27 @@ realloc (void *old, size_t len)
 
   /* Remember the size of the request.  */
   if (len < 65536)
-    catomic_increment (&histogram[len / 16]);
+    atomic_fetch_add_explicit (&histogram[len / 16], 1, memory_order_relaxed);
   else
-    catomic_increment (&large);
+    atomic_fetch_add_explicit (&large, 1, memory_order_relaxed);
   /* Total number of calls of any of the functions.  */
-  catomic_increment (&calls_total);
+  atomic_fetch_add_explicit (&calls_total, 1, memory_order_relaxed);
 
   /* Do the real work.  */
   result = (struct header *) (*reallocp)(real, len + sizeof (struct header));
   if (result == NULL)
     {
-      catomic_increment (&failed[idx_realloc]);
+      atomic_fetch_add_explicit (&failed[idx_realloc], 1,
+				 memory_order_relaxed);
       return NULL;
     }
 
   /* Record whether the reduction/increase happened in place.  */
   if (real == result)
-    catomic_increment (&inplace);
+    atomic_fetch_add_explicit (&inplace, 1, memory_order_relaxed);
   /* Was the buffer increased?  */
   if (old_len > len)
-    catomic_increment (&decreasing);
+    atomic_fetch_add_explicit (&decreasing, 1, memory_order_relaxed);
 
   /* Update the allocation data and write out the records if necessary.  */
   update_data (result, len, old_len);
@@ -508,16 +524,17 @@ calloc (size_t n, size_t len)
     return (*callocp)(n, len);
 
   /* Keep track of number of calls.  */
-  catomic_increment (&calls[idx_calloc]);
+  atomic_fetch_add_explicit (&calls[idx_calloc], 1, memory_order_relaxed);
   /* Keep track of total memory consumption for `calloc'.  */
-  catomic_add (&total[idx_calloc], size);
+  atomic_fetch_add_explicit (&total[idx_calloc], size, memory_order_relaxed);
   /* Keep track of total memory requirement.  */
-  catomic_add (&grand_total, size);
+  atomic_fetch_add_explicit (&grand_total, size, memory_order_relaxed);
   /* Remember the size of the request.  */
   if (size < 65536)
-    catomic_increment (&histogram[size / 16]);
+    atomic_fetch_add_explicit (&histogram[size / 16], 1,
+			       memory_order_relaxed);
   else
-    catomic_increment (&large);
+    atomic_fetch_add_explicit (&large, 1, memory_order_relaxed);
   /* Total number of calls of any of the functions.  */
   ++calls_total;
 
@@ -525,7 +542,8 @@ calloc (size_t n, size_t len)
   result = (struct header *) (*mallocp)(size + sizeof (struct header));
   if (result == NULL)
     {
-      catomic_increment (&failed[idx_calloc]);
+      atomic_fetch_add_explicit (&failed[idx_calloc], 1,
+				 memory_order_relaxed);
       return NULL;
     }
 
@@ -563,7 +581,7 @@ free (void *ptr)
   /* `free (NULL)' has no effect.  */
   if (ptr == NULL)
     {
-      catomic_increment (&calls[idx_free]);
+      atomic_fetch_add_explicit (&calls[idx_free], 1, memory_order_relaxed);
       return;
     }
 
@@ -577,9 +595,10 @@ free (void *ptr)
     }
 
   /* Keep track of number of calls.  */
-  catomic_increment (&calls[idx_free]);
+  atomic_fetch_add_explicit (&calls[idx_free], 1, memory_order_relaxed);
   /* Keep track of total memory freed using `free'.  */
-  catomic_add (&total[idx_free], real->length);
+  atomic_fetch_add_explicit (&total[idx_free], real->length,
+			     memory_order_relaxed);
 
   /* Update the allocation data and write out the records if necessary.  */
   update_data (NULL, 0, real->length);
@@ -614,22 +633,23 @@ mmap (void *start, size_t len, int prot, int flags, int fd, off_t offset)
                  ? idx_mmap_a : prot & PROT_WRITE ? idx_mmap_w : idx_mmap_r);
 
       /* Keep track of number of calls.  */
-      catomic_increment (&calls[idx]);
+      atomic_fetch_add_explicit (&calls[idx], 1, memory_order_relaxed);
       /* Keep track of total memory consumption for `malloc'.  */
-      catomic_add (&total[idx], len);
+      atomic_fetch_add_explicit (&total[idx], len, memory_order_relaxed);
       /* Keep track of total memory requirement.  */
-      catomic_add (&grand_total, len);
+      atomic_fetch_add_explicit (&grand_total, len, memory_order_relaxed);
       /* Remember the size of the request.  */
       if (len < 65536)
-        catomic_increment (&histogram[len / 16]);
+        atomic_fetch_add_explicit (&histogram[len / 16], 1,
+				   memory_order_relaxed);
       else
-        catomic_increment (&large);
+        atomic_fetch_add_explicit (&large, 1, memory_order_relaxed);
       /* Total number of calls of any of the functions.  */
-      catomic_increment (&calls_total);
+      atomic_fetch_add_explicit (&calls_total, 1, memory_order_relaxed);
 
       /* Check for failures.  */
       if (result == NULL)
-        catomic_increment (&failed[idx]);
+        atomic_fetch_add_explicit (&failed[idx], 1, memory_order_relaxed);
       else if (idx == idx_mmap_w)
         /* Update the allocation data and write out the records if
            necessary.  Note the first parameter is NULL which means
@@ -667,22 +687,23 @@ mmap64 (void *start, size_t len, int prot, int flags, int fd, off64_t offset)
                  ? idx_mmap_a : prot & PROT_WRITE ? idx_mmap_w : idx_mmap_r);
 
       /* Keep track of number of calls.  */
-      catomic_increment (&calls[idx]);
+      atomic_fetch_add_explicit (&calls[idx], 1, memory_order_relaxed);
       /* Keep track of total memory consumption for `malloc'.  */
-      catomic_add (&total[idx], len);
+      atomic_fetch_add_explicit (&total[idx], len, memory_order_relaxed);
       /* Keep track of total memory requirement.  */
-      catomic_add (&grand_total, len);
+      atomic_fetch_add_explicit (&grand_total, len, memory_order_relaxed);
       /* Remember the size of the request.  */
       if (len < 65536)
-        catomic_increment (&histogram[len / 16]);
+        atomic_fetch_add_explicit (&histogram[len / 16], 1,
+				   memory_order_relaxed);
       else
-        catomic_increment (&large);
+        atomic_fetch_add_explicit (&large, 1, memory_order_relaxed);
       /* Total number of calls of any of the functions.  */
-      catomic_increment (&calls_total);
+      atomic_fetch_add_explicit (&calls_total, 1, memory_order_relaxed);
 
       /* Check for failures.  */
       if (result == NULL)
-        catomic_increment (&failed[idx]);
+        atomic_fetch_add_explicit (&failed[idx], 1, memory_order_relaxed);
       else if (idx == idx_mmap_w)
         /* Update the allocation data and write out the records if
            necessary.  Note the first parameter is NULL which means
@@ -722,33 +743,39 @@ mremap (void *start, size_t old_len, size_t len, int flags, ...)
   if (!not_me && trace_mmap)
     {
       /* Keep track of number of calls.  */
-      catomic_increment (&calls[idx_mremap]);
+      atomic_fetch_add_explicit (&calls[idx_mremap], 1, memory_order_relaxed);
       if (len > old_len)
         {
           /* Keep track of total memory consumption for `malloc'.  */
-          catomic_add (&total[idx_mremap], len - old_len);
+          atomic_fetch_add_explicit (&total[idx_mremap], len - old_len,
+				     memory_order_relaxed);
           /* Keep track of total memory requirement.  */
-          catomic_add (&grand_total, len - old_len);
+          atomic_fetch_add_explicit (&grand_total, len - old_len,
+				     memory_order_relaxed);
         }
       /* Remember the size of the request.  */
       if (len < 65536)
-        catomic_increment (&histogram[len / 16]);
+        atomic_fetch_add_explicit (&histogram[len / 16], 1,
+				   memory_order_relaxed);
       else
-        catomic_increment (&large);
+        atomic_fetch_add_explicit (&large, 1, memory_order_relaxed);
       /* Total number of calls of any of the functions.  */
-      catomic_increment (&calls_total);
+      atomic_fetch_add_explicit (&calls_total, 1, memory_order_relaxed);
 
       /* Check for failures.  */
       if (result == NULL)
-        catomic_increment (&failed[idx_mremap]);
+        atomic_fetch_add_explicit (&failed[idx_mremap], 1,
+				   memory_order_relaxed);
       else
         {
           /* Record whether the reduction/increase happened in place.  */
           if (start == result)
-            catomic_increment (&inplace_mremap);
+            atomic_fetch_add_explicit (&inplace_mremap, 1,
+				       memory_order_relaxed);
           /* Was the buffer increased?  */
           if (old_len > len)
-            catomic_increment (&decreasing_mremap);
+            atomic_fetch_add_explicit (&decreasing_mremap, 1,
+				       memory_order_relaxed);
 
           /* Update the allocation data and write out the records if
              necessary.  Note the first parameter is NULL which means
@@ -783,19 +810,21 @@ munmap (void *start, size_t len)
   if (!not_me && trace_mmap)
     {
       /* Keep track of number of calls.  */
-      catomic_increment (&calls[idx_munmap]);
+      atomic_fetch_add_explicit (&calls[idx_munmap], 1, memory_order_relaxed);
 
       if (__glibc_likely (result == 0))
         {
           /* Keep track of total memory freed using `free'.  */
-          catomic_add (&total[idx_munmap], len);
+          atomic_fetch_add_explicit (&total[idx_munmap], len,
+				     memory_order_relaxed);
 
           /* Update the allocation data and write out the records if
              necessary.  */
           update_data (NULL, 0, len);
         }
       else
-        catomic_increment (&failed[idx_munmap]);
+        atomic_fetch_add_explicit (&failed[idx_munmap], 1,
+				   memory_order_relaxed);
     }
 
   return result;
-- 
2.34.1

Re: [PATCH v3] malloc: Use C11 atomics on memusage

[DJ Delorie]

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

Adhemerval Zanella <adhemerval.zanella@linaro.org> writes:
> -#include <atomic.h>
> -#include <errno.h>
> -#include <inttypes.h>
> -#include <signal.h>
> -#include <stdarg.h>
> -#include <stdint.h>
> -#include <string.h>
> -#include <unistd.h>

> +#include <stdarg.h>
> +#include <stdatomic.h>
> +#include <unistd.h>

Ok.  I admit I'm also the kind of programmer that block-pastes a
#include list from existing source ;-)

> @@ -73,20 +68,20 @@ struct header
>  #define MAGIC 0xfeedbeaf
>  
>  
> -static unsigned long int calls[idx_last];
> -static unsigned long int failed[idx_last];
> -static size_t total[idx_last];
> -static size_t grand_total;
> -static unsigned long int histogram[65536 / 16];
> -static unsigned long int large;
> -static unsigned long int calls_total;
> -static unsigned long int inplace;
> -static unsigned long int decreasing;
> -static unsigned long int realloc_free;
> -static unsigned long int inplace_mremap;
> -static unsigned long int decreasing_mremap;
> -static size_t current_heap;
> -static size_t peak_use[3];

> +static _Atomic unsigned long int calls[idx_last];
> +static _Atomic unsigned long int failed[idx_last];
> +static _Atomic size_t total[idx_last];
> +static _Atomic size_t grand_total;
> +static _Atomic unsigned long int histogram[65536 / 16];
> +static _Atomic unsigned long int large;
> +static _Atomic unsigned long int calls_total;
> +static _Atomic unsigned long int inplace;
> +static _Atomic unsigned long int decreasing;
> +static _Atomic unsigned long int realloc_free;
> +static _Atomic unsigned long int inplace_mremap;
> +static _Atomic unsigned long int decreasing_mremap;
> +static _Atomic size_t current_heap;
> +static _Atomic size_t peak_use[3];
>  static __thread uintptr_t start_sp;

Ok.

> -static uint32_t buffer_cnt;
> +static _Atomic uint32_t buffer_cnt;

Ok.

> +static inline void
> +peak_atomic_max (_Atomic size_t *peak, size_t val)
> +{
> +  size_t v;
> +  do
> +    {
> +      v = atomic_load_explicit (peak, memory_order_relaxed);
> +      if (v >= val)
> +	break;
> +    }
> +  while (! atomic_compare_exchange_weak (peak, &v, val));
> +}

Ok.

>    /* Compute current heap usage and compare it with the maximum value.  */
>    size_t heap
> -    = catomic_exchange_and_add (&current_heap, len - old_len) + len - old_len;
> -  catomic_max (&peak_heap, heap);
> +    = atomic_fetch_add_explicit (&current_heap, len - old_len,
> +				 memory_order_relaxed) + len - old_len;
> +  peak_atomic_max (&peak_heap, heap);
>  

Ok.

> -  catomic_max (&peak_stack, current_stack);
> +  peak_atomic_max (&peak_stack, current_stack);

Ok.

>    /* Add up heap and stack usage and compare it with the maximum value.  */
> -  catomic_max (&peak_total, heap + current_stack);
> +  peak_atomic_max (&peak_total, heap + current_stack);

Ok.

>    /* Store the value only if we are writing to a file.  */
>    if (fd != -1)
>      {
> -      uint32_t idx = catomic_exchange_and_add (&buffer_cnt, 1);
> +      uint32_t idx = atomic_fetch_add_explicit (&buffer_cnt, 1,
> +						memory_order_relaxed);

Ok.

> -          catomic_compare_and_exchange_val_acq (&buffer_cnt, reset, idx + 1);
> +	  uint32_t expected = idx + 1;
> +	  atomic_compare_exchange_weak (&buffer_cnt, &expected, reset);

Ok.

>    /* Keep track of number of calls.  */
> -  catomic_increment (&calls[idx_malloc]);
> +  atomic_fetch_add_explicit (&calls[idx_malloc], 1, memory_order_relaxed);

Ok.

>    /* Keep track of total memory consumption for `malloc'.  */
> -  catomic_add (&total[idx_malloc], len);
> +  atomic_fetch_add_explicit (&total[idx_malloc], len, memory_order_relaxed);

Ok.

>    /* Keep track of total memory requirement.  */
> -  catomic_add (&grand_total, len);
> +  atomic_fetch_add_explicit (&grand_total, len, memory_order_relaxed);

Ok.

>    /* Remember the size of the request.  */
>    if (len < 65536)
> -    catomic_increment (&histogram[len / 16]);
> +    atomic_fetch_add_explicit (&histogram[len / 16], 1, memory_order_relaxed);
>    else
> -    catomic_increment (&large);
> +    atomic_fetch_add_explicit (&large, 1, memory_order_relaxed);

Ok.

>    /* Total number of calls of any of the functions.  */
> -  catomic_increment (&calls_total);
> +  atomic_fetch_add_explicit (&calls_total, 1, memory_order_relaxed);

Ok.

>    /* Do the real work.  */
>    result = (struct header *) (*mallocp)(len + sizeof (struct header));
>    if (result == NULL)
>      {
> -      catomic_increment (&failed[idx_malloc]);
> +      atomic_fetch_add_explicit (&failed[idx_malloc], 1,
> +				 memory_order_relaxed);
>        return NULL;
>      }

Ok.

>    /* Keep track of number of calls.  */
> -  catomic_increment (&calls[idx_realloc]);
> +  atomic_fetch_add_explicit (&calls[idx_realloc], 1, memory_order_relaxed);

Ok.

>        /* Keep track of total memory consumption for `realloc'.  */
> -      catomic_add (&total[idx_realloc], len - old_len);
> +      atomic_fetch_add_explicit (&total[idx_realloc], len - old_len,
> +				 memory_order_relaxed);

Ok.

>        /* Keep track of total memory requirement.  */
> -      catomic_add (&grand_total, len - old_len);
> +      atomic_fetch_add_explicit (&grand_total, len - old_len,
> +				 memory_order_relaxed);

Ok.

>        /* Special case.  */
> -      catomic_increment (&realloc_free);
> +      atomic_fetch_add_explicit (&realloc_free, 1, memory_order_relaxed);
>        /* Keep track of total memory freed using `free'.  */
> -      catomic_add (&total[idx_free], real->length);
> +      atomic_fetch_add_explicit (&total[idx_free], real->length,
> +				 memory_order_relaxed);

Ok.

>    /* Remember the size of the request.  */
>    if (len < 65536)
> -    catomic_increment (&histogram[len / 16]);
> +    atomic_fetch_add_explicit (&histogram[len / 16], 1, memory_order_relaxed);
>    else
> -    catomic_increment (&large);
> +    atomic_fetch_add_explicit (&large, 1, memory_order_relaxed);

Ok.

>    /* Total number of calls of any of the functions.  */
> -  catomic_increment (&calls_total);
> +  atomic_fetch_add_explicit (&calls_total, 1, memory_order_relaxed);

Ok.

> -      catomic_increment (&failed[idx_realloc]);
> +      atomic_fetch_add_explicit (&failed[idx_realloc], 1,
> +				 memory_order_relaxed);

Ok.

>    if (real == result)
> -    catomic_increment (&inplace);
> +    atomic_fetch_add_explicit (&inplace, 1, memory_order_relaxed);

Ok.

>    /* Was the buffer increased?  */
>    if (old_len > len)
> -    catomic_increment (&decreasing);
> +    atomic_fetch_add_explicit (&decreasing, 1, memory_order_relaxed);

Ok.

>    /* Keep track of number of calls.  */
> -  catomic_increment (&calls[idx_calloc]);
> +  atomic_fetch_add_explicit (&calls[idx_calloc], 1, memory_order_relaxed);

Ok.

>    /* Keep track of total memory consumption for `calloc'.  */
> -  catomic_add (&total[idx_calloc], size);
> +  atomic_fetch_add_explicit (&total[idx_calloc], size, memory_order_relaxed);

Ok.

>    /* Keep track of total memory requirement.  */
> -  catomic_add (&grand_total, size);
> +  atomic_fetch_add_explicit (&grand_total, size, memory_order_relaxed);

Ok.

>    /* Remember the size of the request.  */
>    if (size < 65536)
> -    catomic_increment (&histogram[size / 16]);
> +    atomic_fetch_add_explicit (&histogram[size / 16], 1,
> +			       memory_order_relaxed);

Ok.

>    else
> -    catomic_increment (&large);
> +    atomic_fetch_add_explicit (&large, 1, memory_order_relaxed);

Ok.

> -      catomic_increment (&failed[idx_calloc]);
> +      atomic_fetch_add_explicit (&failed[idx_calloc], 1,
> +				 memory_order_relaxed);

Ok.

> -      catomic_increment (&calls[idx_free]);
> +      atomic_fetch_add_explicit (&calls[idx_free], 1, memory_order_relaxed);

Ok.

>    /* Keep track of number of calls.  */
> -  catomic_increment (&calls[idx_free]);
> +  atomic_fetch_add_explicit (&calls[idx_free], 1, memory_order_relaxed);

Ok.

>    /* Keep track of total memory freed using `free'.  */
> -  catomic_add (&total[idx_free], real->length);
> +  atomic_fetch_add_explicit (&total[idx_free], real->length,
> +			     memory_order_relaxed);

Ok.

>        /* Keep track of number of calls.  */
> -      catomic_increment (&calls[idx]);
> +      atomic_fetch_add_explicit (&calls[idx], 1, memory_order_relaxed);

Ok.

>        /* Keep track of total memory consumption for `malloc'.  */
> -      catomic_add (&total[idx], len);
> +      atomic_fetch_add_explicit (&total[idx], len, memory_order_relaxed);

Ok.

>        /* Keep track of total memory requirement.  */
> -      catomic_add (&grand_total, len);
> +      atomic_fetch_add_explicit (&grand_total, len, memory_order_relaxed);

Ok.

>        /* Remember the size of the request.  */
>        if (len < 65536)
> -        catomic_increment (&histogram[len / 16]);
> +        atomic_fetch_add_explicit (&histogram[len / 16], 1,
> +				   memory_order_relaxed);

Ok.

>        else
> -        catomic_increment (&large);
> +        atomic_fetch_add_explicit (&large, 1, memory_order_relaxed);

Ok.

>        /* Total number of calls of any of the functions.  */
> -      catomic_increment (&calls_total);
> +      atomic_fetch_add_explicit (&calls_total, 1, memory_order_relaxed);

Ok.

>        /* Check for failures.  */
>        if (result == NULL)
> -        catomic_increment (&failed[idx]);
> +        atomic_fetch_add_explicit (&failed[idx], 1, memory_order_relaxed);

Ok.

>        /* Keep track of number of calls.  */
> -      catomic_increment (&calls[idx]);
> +      atomic_fetch_add_explicit (&calls[idx], 1, memory_order_relaxed);

Ok.

>        /* Keep track of total memory consumption for `malloc'.  */
> -      catomic_add (&total[idx], len);
> +      atomic_fetch_add_explicit (&total[idx], len, memory_order_relaxed);

Ok.

>        /* Keep track of total memory requirement.  */
> -      catomic_add (&grand_total, len);
> +      atomic_fetch_add_explicit (&grand_total, len, memory_order_relaxed);

Ok.

>        /* Remember the size of the request.  */
>        if (len < 65536)
> -        catomic_increment (&histogram[len / 16]);
> +        atomic_fetch_add_explicit (&histogram[len / 16], 1,
> +				   memory_order_relaxed);

Ok.

>        else
> -        catomic_increment (&large);
> +        atomic_fetch_add_explicit (&large, 1, memory_order_relaxed);

Ok.

>        /* Total number of calls of any of the functions.  */
> -      catomic_increment (&calls_total);
> +      atomic_fetch_add_explicit (&calls_total, 1, memory_order_relaxed);

Ok.

>        /* Check for failures.  */
>        if (result == NULL)
> -        catomic_increment (&failed[idx]);
> +        atomic_fetch_add_explicit (&failed[idx], 1, memory_order_relaxed);

Ok.

>        /* Keep track of number of calls.  */
> -      catomic_increment (&calls[idx_mremap]);
> +      atomic_fetch_add_explicit (&calls[idx_mremap], 1, memory_order_relaxed);

Ok.

>            /* Keep track of total memory consumption for `malloc'.  */
> -          catomic_add (&total[idx_mremap], len - old_len);
> +          atomic_fetch_add_explicit (&total[idx_mremap], len - old_len,
> +				     memory_order_relaxed);

Ok.

>            /* Keep track of total memory requirement.  */
> -          catomic_add (&grand_total, len - old_len);
> +          atomic_fetch_add_explicit (&grand_total, len - old_len,
> +				     memory_order_relaxed);

Ok.

>        if (len < 65536)
> -        catomic_increment (&histogram[len / 16]);
> +        atomic_fetch_add_explicit (&histogram[len / 16], 1,
> +				   memory_order_relaxed);

Ok.

>        else
> -        catomic_increment (&large);
> +        atomic_fetch_add_explicit (&large, 1, memory_order_relaxed);

Ok.

>        /* Total number of calls of any of the functions.  */
> -      catomic_increment (&calls_total);
> +      atomic_fetch_add_explicit (&calls_total, 1, memory_order_relaxed);

Ok.

>        /* Check for failures.  */
>        if (result == NULL)
> -        catomic_increment (&failed[idx_mremap]);
> +        atomic_fetch_add_explicit (&failed[idx_mremap], 1,
> +				   memory_order_relaxed);

Ok.

>            /* Record whether the reduction/increase happened in place.  */
>            if (start == result)
> -            catomic_increment (&inplace_mremap);
> +            atomic_fetch_add_explicit (&inplace_mremap, 1,
> +				       memory_order_relaxed);

Ok.

>            /* Was the buffer increased?  */
>            if (old_len > len)
> -            catomic_increment (&decreasing_mremap);
> +            atomic_fetch_add_explicit (&decreasing_mremap, 1,
> +				       memory_order_relaxed);

Ok.

>        /* Keep track of number of calls.  */
> -      catomic_increment (&calls[idx_munmap]);
> +      atomic_fetch_add_explicit (&calls[idx_munmap], 1, memory_order_relaxed);

Ok.

>            /* Keep track of total memory freed using `free'.  */
> -          catomic_add (&total[idx_munmap], len);
> +          atomic_fetch_add_explicit (&total[idx_munmap], len,
> +				     memory_order_relaxed);

Ok.

> -        catomic_increment (&failed[idx_munmap]);
> +        atomic_fetch_add_explicit (&failed[idx_munmap], 1,
> +				   memory_order_relaxed);

Ok.

Re: [PATCH v3] malloc: Use C11 atomics on memusage

[Wilco Dijkstra]

Hi,

>Adhemerval Zanella <adhemerval.zanella@linaro.org> writes:
>> -#include <atomic.h>

Just double checking, does this mean we are now happy with bypassing
the internal header, all its defines/checks and target implementations,
and require that all supported targets have correctly implemented C11
atomics?

This would make my outstanding patches on cleaning up atomics a lot
easier, however I'm wondering whether this will "just work" given the
intermediate state will be a mix between C11 atomics and various target
specific hacks. My patches tried hard to avoid such issues by taking
tiny steps in improving this and keeping everything consistent.

Cheers,
Wilco

Re: [PATCH v3] malloc: Use C11 atomics on memusage

[Adhemerval Zanella Netto]

On 03/04/23 10:10, Wilco Dijkstra wrote:
> Hi,
> 
>> Adhemerval Zanella <adhemerval.zanella@linaro.org> writes:
>>> -#include <atomic.h>
> 
> Just double checking, does this mean we are now happy with bypassing
> the internal header, all its defines/checks and target implementations,
> and require that all supported targets have correctly implemented C11
> atomics?

I did it for memusage mainly because it is standalone library that in
theory can be move out glibc (and I might do it, similar to what I did
for libSegfault).

> 
> This would make my outstanding patches on cleaning up atomics a lot
> easier, however I'm wondering whether this will "just work" given the
> intermediate state will be a mix between C11 atomics and various target
> specific hacks. My patches tried hard to avoid such issues by taking
> tiny steps in improving this and keeping everything consistent.

I think for internal usage, we might still use the internal atomic.h. 
Maybe what we can do it to fist move all the internal code to the
C11-like interface and then check if we can move to compiler builtins.