svn commit: r344269 - head/lib/libmemstat

[Gleb Smirnoff]

Author: glebius
Date: Mon Feb 18 21:27:13 2019
New Revision: 344269
URL: https://svnweb.freebsd.org/changeset/base/344269

Log:
  With r343051 UMA switched from atomic counts to counter(9) and now kernel
  reports snap counts of how much a zone alloced and how much it freed.  It
  may happen that snap values doesn't match, e.g alloced - freed < 0.
  Workaround that in memstat library.
  
  Reported by:	pho

Modified:
  head/lib/libmemstat/memstat_uma.c

Modified: head/lib/libmemstat/memstat_uma.c
==============================================================================
--- head/lib/libmemstat/memstat_uma.c	Mon Feb 18 20:29:19 2019	(r344268)
+++ head/lib/libmemstat/memstat_uma.c	Mon Feb 18 21:27:13 2019	(r344269)
@@ -213,6 +213,15 @@ retry:
 			mtp->mt_numfrees += upsp->ups_frees;
 		}
 
+		/*
+		 * Values for uth_allocs and uth_frees frees are snap.
+		 * It may happen that kernel reports that number of frees
+		 * is greater than number of allocs. See counter(9) for
+		 * details.
+		 */
+		if (mtp->mt_numallocs < mtp->mt_numfrees)
+			mtp->mt_numallocs = mtp->mt_numfrees;
+
 		mtp->mt_size = uthp->uth_size;
 		mtp->mt_rsize = uthp->uth_rsize;
 		mtp->mt_memalloced = mtp->mt_numallocs * uthp->uth_size;