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Date:      Tue, 6 Mar 2018 16:10:47 +0000 (UTC)
From:      Mark Johnston <markj@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-user@freebsd.org
Subject:   svn commit: r330543 - user/markj/vm-playground/sys/vm
Message-ID:  <201803061610.w26GAlJ1073326@repo.freebsd.org>
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Author: markj
Date: Tue Mar  6 16:10:47 2018
New Revision: 330543
URL: https://svnweb.freebsd.org/changeset/base/330543

Log:
  Batch updates to a reservation's population map.
  
  Each such update causes the reservation to be requeued in the per-domain
  partially populated reservation queue, preserving LRU. The queue is
  protected by the per-domain reservation lock. Now that
  vm_reserv_extend() and vm_reserv_alloc_page() opportunistically return
  multiple consecutive pages to support vm_page_alloc_pages_after(), it is
  beneficial to requeue the reservation only after all popmap updates are
  finished, rather than requeuing once per page. This also helps with
  contiguous allocation requests, which may also return multiple pages
  depending on the request constraints.

Modified:
  user/markj/vm-playground/sys/vm/vm_reserv.c

Modified: user/markj/vm-playground/sys/vm/vm_reserv.c
==============================================================================
--- user/markj/vm-playground/sys/vm/vm_reserv.c	Tue Mar  6 15:52:43 2018	(r330542)
+++ user/markj/vm-playground/sys/vm/vm_reserv.c	Tue Mar  6 16:10:47 2018	(r330543)
@@ -280,7 +280,8 @@ static void		vm_reserv_depopulate(vm_reserv_t rv, int 
 static vm_reserv_t	vm_reserv_from_page(vm_page_t m);
 static boolean_t	vm_reserv_has_pindex(vm_reserv_t rv,
 			    vm_pindex_t pindex);
-static void		vm_reserv_populate(vm_reserv_t rv, int index);
+static void		vm_reserv_populate(vm_reserv_t rv, int index,
+			    int count);
 static void		vm_reserv_reclaim(vm_reserv_t rv);
 
 /*
@@ -523,10 +524,10 @@ vm_reserv_has_pindex(vm_reserv_t rv, vm_pindex_t pinde
  * Increases the given reservation's population count.  Moves the reservation
  * to the tail of the partially populated reservation queue.
  *
- * The free page queue must be locked.
+ * The reservation must be locked.
  */
 static void
-vm_reserv_populate(vm_reserv_t rv, int index)
+vm_reserv_populate(vm_reserv_t rv, int index, int count)
 {
 
 	vm_reserv_assert_locked(rv);
@@ -534,18 +535,21 @@ vm_reserv_populate(vm_reserv_t rv, int index)
 	    __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq);
 	KASSERT(rv->object != NULL,
 	    ("vm_reserv_populate: reserv %p is free", rv));
-	KASSERT(popmap_is_clear(rv->popmap, index),
-	    ("vm_reserv_populate: reserv %p's popmap[%d] is set", rv,
-	    index));
-	KASSERT(rv->popcnt < VM_LEVEL_0_NPAGES,
+	KASSERT(rv->popcnt >= 0 && rv->popcnt + count <= VM_LEVEL_0_NPAGES,
 	    ("vm_reserv_populate: reserv %p is already full", rv));
 	KASSERT(rv->pages->psind == 0,
 	    ("vm_reserv_populate: reserv %p is already promoted", rv));
 	KASSERT(rv->domain >= 0 && rv->domain < vm_ndomains,
 	    ("vm_reserv_populate: reserv %p's domain is corrupted %d",
 	    rv, rv->domain));
-	popmap_set(rv->popmap, index);
-	rv->popcnt++;
+
+	rv->popcnt += count;
+	for (; count > 0; count--, index++) {
+		KASSERT(popmap_is_clear(rv->popmap, index),
+		    ("vm_reserv_populate: reserv %p's popmap[%d] is set", rv,
+		    index));
+		popmap_set(rv->popmap, index);
+	}
 	vm_reserv_domain_lock(rv->domain);
 	if (rv->inpartpopq) {
 		TAILQ_REMOVE(&vm_rvq_partpop[rv->domain], rv, partpopq);
@@ -645,8 +649,7 @@ vm_reserv_extend_contig(int req, vm_object_t object, v
 	}
 	if (vm_domain_allocate(vmd, req, npages, false) == 0)
 		goto out;
-	for (i = 0; i < npages; i++)
-		vm_reserv_populate(rv, index + i);
+	vm_reserv_populate(rv, index, npages);
 	vm_reserv_unlock(rv);
 	return (m);
 
@@ -681,7 +684,7 @@ vm_reserv_alloc_contig(int req, vm_object_t object, vm
 	vm_pindex_t first, leftcap, rightcap;
 	vm_reserv_t rv;
 	u_long allocpages, maxpages, minpages;
-	int i, index, n;
+	int index, n;
 
 	VM_OBJECT_ASSERT_WLOCKED(object);
 	KASSERT(npages != 0, ("vm_reserv_alloc_contig: npages is 0"));
@@ -823,8 +826,7 @@ vm_reserv_alloc_contig(int req, vm_object_t object, vm
 		vm_reserv_lock(rv);
 		vm_reserv_insert(rv, object, first);
 		n = ulmin(VM_LEVEL_0_NPAGES - index, npages);
-		for (i = 0; i < n; i++)
-			vm_reserv_populate(rv, index + i);
+		vm_reserv_populate(rv, index, n);
 		npages -= n;
 		if (m_ret == NULL) {
 			m_ret = &rv->pages[index];
@@ -898,18 +900,16 @@ vm_reserv_extend(int req, vm_object_t object, vm_pinde
 	 */
 	nalloc = countp != NULL ? imin(VM_LEVEL_0_NPAGES - index, *countp) : 1;
 	if ((avail = vm_domain_allocate(vmd, req, nalloc, true)) > 0) {
-		vm_reserv_populate(rv, index);
 		if (countp != NULL) {
-			for (nalloc = 1; nalloc < avail; nalloc++) {
-				if (popmap_is_set(rv->popmap, ++index))
+			for (nalloc = 1; nalloc < avail; nalloc++)
+				if (popmap_is_set(rv->popmap, index + nalloc))
 					break;
-				vm_reserv_populate(rv, index);
-			}
 			if (nalloc < avail)
 				/* Return leftover pages. */
 				vm_domain_freecnt_inc(vmd, avail - nalloc);
 			*countp = nalloc;
 		}
+		vm_reserv_populate(rv, index, nalloc);
 	} else
 		m = NULL;
 out:
@@ -1033,19 +1033,17 @@ vm_reserv_alloc_page(int req, vm_object_t object, vm_p
 	KASSERT(rv->pages == m,
 	    ("vm_reserv_alloc_page: reserv %p's pages is corrupted", rv));
 	vm_reserv_insert(rv, object, first);
-	vm_reserv_populate(rv, index);
 	m = &rv->pages[index];
 	if (countp != NULL) {
-		for (nalloc = 1; nalloc < avail; nalloc++) {
-			if (popmap_is_set(rv->popmap, ++index))
+		for (nalloc = 1; nalloc < avail; nalloc++)
+			if (popmap_is_set(rv->popmap, index + nalloc))
 				break;
-			vm_reserv_populate(rv, index);
-		}
 		if (nalloc < avail)
 			/* Return leftover pages. */
 			vm_domain_freecnt_inc(vmd, avail - nalloc);
 		*countp = nalloc;
 	}
+	vm_reserv_populate(rv, index, nalloc);
 	vm_reserv_unlock(rv);
 
 	return (m);

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