Additional Linux VM integration

Added support for Solaris swapfs_minfree, and swapfs_reserve tunables.
In additional availrmem is now available and return a reasonable value
which is reasonably analogous to the Solaris meaning.  On linux we
return the sun of free and inactive pages since these are all easily
reclaimable.

All tunables are available in /proc/sys/kernel/spl/vm/* and they may
need a little adjusting once we observe the real behavior.  Some of
the defaults are mapped to similar linux counterparts, others are
straight from the OpenSolaris defaults.

1 files changed, 77 insertions, 9 deletions

diff --git a/module/spl/spl-kmem.c b/module/spl/spl-kmem.c
index c39636e06..b5cd9fb12 100644
--- a/module/spl/spl-kmem.c
+++ b/module/spl/spl-kmem.c
@@ -64,18 +64,12 @@ EXPORT_SYMBOL(lotsfree);
 pgcnt_t needfree = 0;
 EXPORT_SYMBOL(needfree);
 
-pgcnt_t swapfs_desfree = 0;
-EXPORT_SYMBOL(swapfs_desfree);
-
 pgcnt_t swapfs_minfree = 0;
 EXPORT_SYMBOL(swapfs_minfree);
 
 pgcnt_t swapfs_reserve = 0;
 EXPORT_SYMBOL(swapfs_reserve);
 
-pgcnt_t availrmem = 0;
-EXPORT_SYMBOL(availrmem);
-
 vmem_t *heap_arena = NULL;
 EXPORT_SYMBOL(heap_arena);
 
@@ -86,14 +80,17 @@ vmem_t *zio_arena = NULL;
 EXPORT_SYMBOL(zio_arena);
 
 #ifndef HAVE_FIRST_ONLINE_PGDAT
-struct pglist_data *first_online_pgdat(void)
+struct pglist_data *
+first_online_pgdat(void)
 {
 	return NODE_DATA(first_online_node);
 }
+EXPORT_SYMBOL(first_online_pgdat);
 #endif /* HAVE_FIRST_ONLINE_PGDAT */
 
 #ifndef HAVE_NEXT_ONLINE_PGDAT
-struct pglist_data *next_online_pgdat(struct pglist_data *pgdat)
+struct pglist_data *
+next_online_pgdat(struct pglist_data *pgdat)
 {
 	int nid = next_online_node(pgdat->node_id);
 
@@ -102,10 +99,12 @@ struct pglist_data *next_online_pgdat(struct pglist_data *pgdat)
 
 	return NODE_DATA(nid);
 }
+EXPORT_SYMBOL(next_online_pgdat);
 #endif /* HAVE_NEXT_ONLINE_PGDAT */
 
 #ifndef HAVE_NEXT_ZONE
-struct zone *next_zone(struct zone *zone)
+struct zone *
+next_zone(struct zone *zone)
 {
 	pg_data_t *pgdat = zone->zone_pgdat;
 
@@ -120,8 +119,73 @@ struct zone *next_zone(struct zone *zone)
 	}
 	return zone;
 }
+EXPORT_SYMBOL(next_zone);
 #endif /* HAVE_NEXT_ZONE */
 
+#ifndef HAVE_GET_ZONE_COUNTS
+void
+__get_zone_counts(unsigned long *active, unsigned long *inactive,
+                  unsigned long *free, struct pglist_data *pgdat)
+{
+	struct zone *zones = pgdat->node_zones;
+	int i;
+
+	*active = 0;
+	*inactive = 0;
+	*free = 0;
+	for (i = 0; i < MAX_NR_ZONES; i++) {
+		*active += zones[i].nr_active;
+		*inactive += zones[i].nr_inactive;
+		*free += zones[i].free_pages;
+	}
+}
+
+void
+get_zone_counts(unsigned long *active, unsigned long *inactive,
+                unsigned long *free)
+{
+	struct pglist_data *pgdat;
+
+	*active = 0;
+	*inactive = 0;
+	*free = 0;
+	for_each_online_pgdat(pgdat) {
+		unsigned long l, m, n;
+		__get_zone_counts(&l, &m, &n, pgdat);
+		*active += l;
+		*inactive += m;
+		*free += n;
+	}
+}
+EXPORT_SYMBOL(get_zone_counts);
+#endif /* HAVE_GET_ZONE_COUNTS */
+
+pgcnt_t
+spl_kmem_availrmem(void)
+{
+	unsigned long active;
+	unsigned long inactive;
+	unsigned long free;
+
+	get_zone_counts(&active, &inactive, &free);
+
+	/* The amount of easily available memory */
+	return free + inactive;
+}
+EXPORT_SYMBOL(spl_kmem_availrmem);
+
+size_t
+vmem_size(vmem_t *vmp, int typemask)
+{
+	/* Arena's unsupported */
+	ASSERT(vmp == NULL);
+	ASSERT(typemask & (VMEM_ALLOC | VMEM_FREE));
+
+	return 0;
+}
+EXPORT_SYMBOL(vmem_size);
+
+
 /*
  * Memory allocation interfaces and debugging for basic kmem_*
  * and vmem_* style memory allocation.  When DEBUG_KMEM is enable
@@ -1707,6 +1771,10 @@ spl_kmem_init_globals(void)
 		desfree += zone->pages_low;
 		lotsfree += zone->pages_high;
 	}
+
+	/* Solaris default values */
+	swapfs_minfree = MAX(2*1024*1024 / PAGE_SIZE, physmem / 8);
+	swapfs_reserve = MIN(4*1024*1024 / PAGE_SIZE, physmem / 16);
 }
 
 int