[PATCH] Core: monitoring anonymous map on Darwin platform

[David Carlier]

# HG changeset patch
# User David Carlier <devnexen at gmail.com>
# Date 1566493379 -3600
#      Thu Aug 22 18:02:59 2019 +0100
# Node ID adc68231e590554860b11ee851b293e46ba652db
# Parent  9f1f9d6e056a4f85907957ef263f78a426ae4f9c
Core: monitoring anonymous map on Darwin platform.

Allows to highligh those pages from nginx process with
this identifier.

diff -r 9f1f9d6e056a -r adc68231e590 auto/os/darwin
--- a/auto/os/darwin	Mon Aug 19 15:16:06 2019 +0300
+++ b/auto/os/darwin	Thu Aug 22 18:02:59 2019 +0100
@@ -118,3 +118,21 @@
 ngx_feature_test="int32_t  lock = 0;
                   if (!OSAtomicCompareAndSwap32Barrier(0, 1, &lock)) return 1"
 . auto/feature
+
+# Darwin can tag anonymous pages to be tracked
+# with tools like vmmap
+# free ID are guaranteed to be free from 240 to 255
+# for userland applications
+
+ngx_feature="Darwin tags anonymous pages"
+ngx_feature_name=NGX_HAVE_MAP_ANON_TAG
+ngx_feature_run=yes
+ngx_feature_incs="#include <sys/mman.h>
+                  #include <mach/vm_statistics.h>"
+ngx_feature_path=
+ngx_feature_libs=
+ngx_feature_test="void *p = mmap(NULL, 16, PROT_READ, MAP_PRIVATE|MAP_ANON, VM_MAKE_TAG(240), 0);
+                  if (p == MAP_FAILED) return 1;
+                  munmap(p, 16)"
+
+. auto/feature
diff -r 9f1f9d6e056a -r adc68231e590 src/os/unix/ngx_darwin_config.h
--- a/src/os/unix/ngx_darwin_config.h	Mon Aug 19 15:16:06 2019 +0300
+++ b/src/os/unix/ngx_darwin_config.h	Thu Aug 22 18:02:59 2019 +0100
@@ -76,6 +76,10 @@
 #include <sys/event.h>
 #endif
 
+#if (NGX_HAVE_MAP_ANON_TAG)
+#include <mach/vm_statistics.h>
+#endif
+
 
 #define NGX_LISTEN_BACKLOG  -1
 
diff -r 9f1f9d6e056a -r adc68231e590 src/os/unix/ngx_shmem.c
--- a/src/os/unix/ngx_shmem.c	Mon Aug 19 15:16:06 2019 +0300
+++ b/src/os/unix/ngx_shmem.c	Thu Aug 22 18:02:59 2019 +0100
@@ -14,9 +14,16 @@
 ngx_int_t
 ngx_shm_alloc(ngx_shm_t *shm)
 {
+    ngx_fd_t fd;
+
+#if (NGX_HAVE_MAP_ANON_TAG)
+    fd = VM_MAKE_TAG(246);
+#else
+    fd = -1;
+#endif
     shm->addr = (u_char *) mmap(NULL, shm->size,
                                 PROT_READ|PROT_WRITE,
-                                MAP_ANON|MAP_SHARED, -1, 0);
+                                MAP_ANON|MAP_SHARED, fd, 0);
 
     if (shm->addr == MAP_FAILED) {
         ngx_log_error(NGX_LOG_ALERT, shm->log, ngx_errno,