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Date:      Sat, 25 Feb 2017 16:39:21 +0000 (UTC)
From:      Andriy Gapon <avg@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r314272 - head/sys/vm
Message-ID:  <201702251639.v1PGdL9s032894@repo.freebsd.org>
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Author: avg
Date: Sat Feb 25 16:39:21 2017
New Revision: 314272
URL: https://svnweb.freebsd.org/changeset/base/314272

Log:
  call vm_lowmem hook in uma_reclaim_worker
  
  A comment near kmem_reclaim() implies that we already did that.
  Calling the hook is useful, because some handlers, e.g. ARC,
  might be able to release significant amounts of KVA.
  
  Now that we have more than one place where vm_lowmem hook is called,
  use this change as an opportunity to introduce flags that describe
  a reason for calling the hook.  No handler makes use of the flags yet.
  
  Reviewed by:	markj, kib
  MFC after:	1 week
  Sponsored by:	Panzura
  Differential Revision: https://reviews.freebsd.org/D9764

Modified:
  head/sys/vm/uma_core.c
  head/sys/vm/vm_kern.c
  head/sys/vm/vm_pageout.c
  head/sys/vm/vm_pageout.h

Modified: head/sys/vm/uma_core.c
==============================================================================
--- head/sys/vm/uma_core.c	Sat Feb 25 15:55:46 2017	(r314271)
+++ head/sys/vm/uma_core.c	Sat Feb 25 16:39:21 2017	(r314272)
@@ -64,6 +64,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/bitset.h>
+#include <sys/eventhandler.h>
 #include <sys/kernel.h>
 #include <sys/types.h>
 #include <sys/queue.h>
@@ -3199,6 +3200,9 @@ uma_reclaim_worker(void *arg __unused)
 		    "umarcl", 0);
 		if (uma_reclaim_needed) {
 			uma_reclaim_needed = 0;
+			sx_xunlock(&uma_drain_lock);
+			EVENTHANDLER_INVOKE(vm_lowmem, VM_LOW_KMEM);
+			sx_xlock(&uma_drain_lock);
 			uma_reclaim_locked(true);
 		}
 	}

Modified: head/sys/vm/vm_kern.c
==============================================================================
--- head/sys/vm/vm_kern.c	Sat Feb 25 15:55:46 2017	(r314271)
+++ head/sys/vm/vm_kern.c	Sat Feb 25 16:39:21 2017	(r314272)
@@ -552,11 +552,13 @@ debug_vm_lowmem(SYSCTL_HANDLER_ARGS)
 	error = sysctl_handle_int(oidp, &i, 0, req);
 	if (error)
 		return (error);
-	if (i)	 
-		EVENTHANDLER_INVOKE(vm_lowmem, 0);
+	if ((i & ~(VM_LOW_KMEM | VM_LOW_PAGES)) != 0)
+		return (EINVAL);
+	if (i != 0)
+		EVENTHANDLER_INVOKE(vm_lowmem, i);
 	return (0);
 }
 
 SYSCTL_PROC(_debug, OID_AUTO, vm_lowmem, CTLTYPE_INT | CTLFLAG_RW, 0, 0,
-    debug_vm_lowmem, "I", "set to trigger vm_lowmem event");
+    debug_vm_lowmem, "I", "set to trigger vm_lowmem event with given flags");
 #endif

Modified: head/sys/vm/vm_pageout.c
==============================================================================
--- head/sys/vm/vm_pageout.c	Sat Feb 25 15:55:46 2017	(r314271)
+++ head/sys/vm/vm_pageout.c	Sat Feb 25 16:39:21 2017	(r314272)
@@ -1332,7 +1332,7 @@ vm_pageout_scan(struct vm_domain *vmd, i
 		 * Decrease registered cache sizes.
 		 */
 		SDT_PROBE0(vm, , , vm__lowmem_scan);
-		EVENTHANDLER_INVOKE(vm_lowmem, 0);
+		EVENTHANDLER_INVOKE(vm_lowmem, VM_LOW_PAGES);
 		/*
 		 * We do this explicitly after the caches have been
 		 * drained above.

Modified: head/sys/vm/vm_pageout.h
==============================================================================
--- head/sys/vm/vm_pageout.h	Sat Feb 25 15:55:46 2017	(r314271)
+++ head/sys/vm/vm_pageout.h	Sat Feb 25 16:39:21 2017	(r314272)
@@ -87,6 +87,12 @@ extern bool vm_pages_needed;
 #define	VM_OOM_SWAPZ	2
 
 /*
+ * vm_lowmem flags.
+ */
+#define	VM_LOW_KMEM	0x01
+#define	VM_LOW_PAGES	0x02
+
+/*
  *	Exported routines.
  */

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