svn commit: r319627 - head/sys/vm

[Alan Cox]

Author: alc
Date: Tue Jun  6 16:52:07 2017
New Revision: 319627
URL: https://svnweb.freebsd.org/changeset/base/319627

Log:
  Starting in r118390, swaponsomething() began to reserve the blocks at the
  beginning of a swap area for a disk label.  However, neither r118390 nor
  r118544, which increased the reservation from one to two blocks, correctly
  accounted for these blocks when updating the variable "swap_pager_avail".
  This change corrects that error.
  
  Reviewed by:	kib
  MFC after:	5 days

Modified:
  head/sys/vm/swap_pager.c

Modified: head/sys/vm/swap_pager.c
==============================================================================
--- head/sys/vm/swap_pager.c	Tue Jun  6 16:04:27 2017	(r319626)
+++ head/sys/vm/swap_pager.c	Tue Jun  6 16:52:07 2017	(r319627)
@@ -2203,7 +2203,7 @@ swaponsomething(struct vnode *vp, void *id, u_long nbl
 	sp->sw_end = dvbase + nblks;
 	TAILQ_INSERT_TAIL(&swtailq, sp, sw_list);
 	nswapdev++;
-	swap_pager_avail += nblks;
+	swap_pager_avail += nblks - 2;
 	swap_total += (vm_ooffset_t)nblks * PAGE_SIZE;
 	swapon_check_swzone(swap_total / PAGE_SIZE);
 	swp_sizecheck();