[libgtop] freebsd: rework system memory usage

[Ting-Wei Lan <lantw src gnome org>]

commit a206cfc72822ab45d19d9700ccb348fa1cd290d9
Author: Ting-Wei Lan <lantw src gnome org>
Date:   Sat May 2 21:36:22 2015 +0800

    freebsd: rework system memory usage
    
    Change the value of memory usage from:
    
      Used   = Wired
      Free   = Total - Wired
      Shared = 0
      Buffer = 0
      Cached = Cache
      User   = Wired - Cache
      Locked = Not Supported
    
    To:
    
      Used   = Total - Free
      Free   = Free
      Shared = 0
      Buffer = Buf
      Cached = Cache
      User   = Active + Wired
      Locked = Not Supported
    
    The left-hand side means fields in the glibtop_mem struct and the right-hand
    side means the value showed by `top' command. This change should make the value
    showed by gnome-system-monitor, which uses `User' field, become closer to
    the real memory usage.
    
    All sysctlbyname code in sysdeps/freebsd/mem.c has been moved to separate
    functions to make the code cleaner.

 sysdeps/freebsd/mem.c |   67 ++++++++++++++++++++++++++++--------------------
 1 files changed, 39 insertions(+), 28 deletions(-)
---
diff --git a/sysdeps/freebsd/mem.c b/sysdeps/freebsd/mem.c
index 3e1d4ab..a9e9d25 100644
--- a/sysdeps/freebsd/mem.c
+++ b/sysdeps/freebsd/mem.c
@@ -45,46 +45,57 @@ _glibtop_init_mem_s (glibtop *server)
        server->sysdeps.mem = _glibtop_sysdeps_mem;
 }
 
+static gulong mem_get_by_bytes (glibtop *server, const char *name) {
+       gulong result = 0;
+       size_t len = sizeof (result);
+
+       if (sysctlbyname (name, &result, &len, NULL, 0)) {
+               glibtop_warn_io_r (server, "sysctl (%s)", name);
+       }
+       return result;
+}
+
+static gulong mem_get_by_pages (glibtop *server, const char *name) {
+       guint result = 0;
+       size_t len = sizeof (result);
+
+       if (sysctlbyname (name, &result, &len, NULL, 0)) {
+               glibtop_warn_io_r (server, "sysctl (%s)", name);
+       }
+       return (gulong) result * pagesize;
+}
+
 void
 glibtop_get_mem_s (glibtop *server, glibtop_mem *buf)
 {
        gulong memtotal;
-       guint memused;
-       gulong buffers;
-       guint cached;
-       size_t len;
+       gulong memactive;
+       gulong meminactive;
+       gulong memwired;
+       gulong memcached;
+       gulong membuffer;
+       gulong memfree;
 
        glibtop_init_s (&server, GLIBTOP_SYSDEPS_MEM, 0);
 
        memset (buf, 0, sizeof *buf);
 
-       len = sizeof (memtotal);
-       if (sysctlbyname ("hw.physmem", &memtotal, &len, NULL, 0)) {
-               glibtop_warn_io_r (server, "sysctl (hw.physmem)");
-               return;
-       }
-
-       len = sizeof (memused);
-       if (sysctlbyname ("vm.stats.vm.v_wire_count", &memused, &len, NULL, 0)) {
-               glibtop_warn_io_r (server, "sysctl (vm.stats.vm.v_wire_count)");
-               return;
-       }
-
-       len = sizeof (cached);
-       if (sysctlbyname ("vm.stats.vm.v_cache_count", &cached, &len, NULL, 0)) {
-               glibtop_warn_io_r (server, "sysctl (vm.stats.vm.v_cache_count)");
-               return;
-       }
-
-       buffers = 0;
+       memtotal = mem_get_by_bytes (server, "hw.physmem");
+       memactive = mem_get_by_pages (server, "vm.stats.vm.v_active_count");
+       meminactive = mem_get_by_pages (server, "vm.stats.vm.v_inactive_count");
+       memwired = mem_get_by_pages (server, "vm.stats.vm.v_wire_count");
+       memcached = mem_get_by_pages (server, "vm.stats.vm.v_cache_count");
+       membuffer = mem_get_by_bytes (server, "vfs.bufspace");
+       memfree = mem_get_by_pages (server, "vm.stats.vm.v_free_count");
 
        buf->total = memtotal;
-       buf->used = (memused * (gulong) pagesize);
-       buf->free = (buf->total - buf->used);
+       buf->used = memtotal - memfree;
+       buf->free = memfree;
        buf->shared = 0;
-       buf->cached = (cached * (gulong) pagesize);
-       buf->buffer = buffers;
+       buf->buffer = membuffer;
+       buf->cached = memcached;
+       buf->locked = 0;
 
-       buf->user = buf->total - buf->free - buf->cached - buf->buffer;
+       buf->user = memactive + memwired;
        buf->flags = _glibtop_sysdeps_mem;
 }