svn commit: r234513 - stable/8/sys/fs/tmpfs

[Xin LI]

Author: delphij
Date: Fri Apr 20 22:27:10 2012
New Revision: 234513
URL: http://svn.freebsd.org/changeset/base/234513

Log:
  MFC r227802:
  
  Improve the way to calculate available pages in tmpfs:
  
   - Don't deduct wired pages from total usable counts because it does not
     make any sense.  To make things worse, on systems where swap size is
     smaller than physical memory and use a lot of wired pages (e.g. ZFS),
     tmpfs can suddenly have free space of 0 because of this;
   - Count cached pages as available; [1]
   - Don't count inactive pages as available, technically we could but that
     might be too aggressive; [1]
  
  [1] Suggested by kib@

Modified:
  stable/8/sys/fs/tmpfs/tmpfs.h
Directory Properties:
  stable/8/sys/   (props changed)

Modified: stable/8/sys/fs/tmpfs/tmpfs.h
==============================================================================
--- stable/8/sys/fs/tmpfs/tmpfs.h	Fri Apr 20 22:16:08 2012	(r234512)
+++ stable/8/sys/fs/tmpfs/tmpfs.h	Fri Apr 20 22:27:10 2012	(r234513)
@@ -483,11 +483,8 @@ int	tmpfs_truncate(struct vnode *, off_t
 static __inline size_t
 tmpfs_mem_info(void)
 {
-	size_t size;
 
-	size = swap_pager_avail + cnt.v_free_count + cnt.v_inactive_count;
-	size -= size > cnt.v_wire_count ? cnt.v_wire_count : size;
-	return size;
+	return (swap_pager_avail + cnt.v_free_count + cnt.v_cache_count);
 }
 
 /* Returns the maximum size allowed for a tmpfs file system.  This macro