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Date:      Thu, 8 Jun 2017 15:48:54 +0000 (UTC)
From:      Alan Cox <alc@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r319699 - head/sys/kern
Message-ID:  <201706081548.v58FmsJo053788@repo.freebsd.org>

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Author: alc
Date: Thu Jun  8 15:48:54 2017
New Revision: 319699
URL: https://svnweb.freebsd.org/changeset/base/319699

Log:
  When allocating swap blocks, if the available number of free blocks in a
  subtree is already zero, then setting the "largest contiguous free block"
  hint for that subtree to anything other than zero makes no sense.  To be
  clear, assigning a value to the hint that is too large is not a correctness
  problem, only a pessimization.
  
  Dragonfly BSD has applied the same change to blst_meta_alloc() but not
  blst_meta_fill().
  
  MFC after:	6 weeks

Modified:
  head/sys/kern/subr_blist.c

Modified: head/sys/kern/subr_blist.c
==============================================================================
--- head/sys/kern/subr_blist.c	Thu Jun  8 15:47:52 2017	(r319698)
+++ head/sys/kern/subr_blist.c	Thu Jun  8 15:48:54 2017	(r319699)
@@ -419,7 +419,7 @@ blst_meta_alloc(
 		/*
 		 * ALL-ALLOCATED special case
 		 */
-		scan->bm_bighint = count;
+		scan->bm_bighint = 0;
 		return(SWAPBLK_NONE);
 	}
 
@@ -774,7 +774,7 @@ blst_meta_fill(
 		 */
 		nblks = scan->u.bmu_avail;
 		scan->u.bmu_avail = 0;
-		scan->bm_bighint = count;
+		scan->bm_bighint = 0;
 		return nblks;
 	}
 



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