summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorIgor Redko <redkoi@virtuozzo.com>2016-03-17 14:19:05 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-03-17 15:09:34 -0700
commitd02bd27bd33dd7e8d22594cd568b81be0cb584cd (patch)
treee8bbd51013b90f2b9cf6ea239128f9da1f714e55
parent7eb50292d7f74ccb89155960d62b2697f2536b28 (diff)
mm/page_alloc.c: calculate 'available' memory in a separate function
Add a new field, VIRTIO_BALLOON_S_AVAIL, to virtio_balloon memory statistics protocol, corresponding to 'Available' in /proc/meminfo. It indicates to the hypervisor how big the balloon can be inflated without pushing the guest system to swap. This metric would be very useful in VM orchestration software to improve memory management of different VMs under overcommit. This patch (of 2): Factor out calculation of the available memory counter into a separate exportable function, in order to be able to use it in other parts of the kernel. In particular, it appears a relevant metric to report to the hypervisor via virtio-balloon statistics interface (in a followup patch). Signed-off-by: Igor Redko <redkoi@virtuozzo.com> Signed-off-by: Denis V. Lunev <den@openvz.org> Reviewed-by: Roman Kagan <rkagan@virtuozzo.com> Cc: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/proc/meminfo.c31
-rw-r--r--include/linux/mm.h1
-rw-r--r--mm/page_alloc.c43
3 files changed, 45 insertions, 30 deletions
diff --git a/fs/proc/meminfo.c b/fs/proc/meminfo.c
index df4661abadc4..83720460c5bc 100644
--- a/fs/proc/meminfo.c
+++ b/fs/proc/meminfo.c
@@ -29,10 +29,7 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
unsigned long committed;
long cached;
long available;
- unsigned long pagecache;
- unsigned long wmark_low = 0;
unsigned long pages[NR_LRU_LISTS];
- struct zone *zone;
int lru;
/*
@@ -51,33 +48,7 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
for (lru = LRU_BASE; lru < NR_LRU_LISTS; lru++)
pages[lru] = global_page_state(NR_LRU_BASE + lru);
- for_each_zone(zone)
- wmark_low += zone->watermark[WMARK_LOW];
-
- /*
- * Estimate the amount of memory available for userspace allocations,
- * without causing swapping.
- */
- available = i.freeram - totalreserve_pages;
-
- /*
- * Not all the page cache can be freed, otherwise the system will
- * start swapping. Assume at least half of the page cache, or the
- * low watermark worth of cache, needs to stay.
- */
- pagecache = pages[LRU_ACTIVE_FILE] + pages[LRU_INACTIVE_FILE];
- pagecache -= min(pagecache / 2, wmark_low);
- available += pagecache;
-
- /*
- * Part of the reclaimable slab consists of items that are in use,
- * and cannot be freed. Cap this estimate at the low watermark.
- */
- available += global_page_state(NR_SLAB_RECLAIMABLE) -
- min(global_page_state(NR_SLAB_RECLAIMABLE) / 2, wmark_low);
-
- if (available < 0)
- available = 0;
+ available = si_mem_available();
/*
* Tagged format, for easy grepping and expansion.
diff --git a/include/linux/mm.h b/include/linux/mm.h
index b3202612bb95..db9df3f78de1 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1875,6 +1875,7 @@ extern int __meminit init_per_zone_wmark_min(void);
extern void mem_init(void);
extern void __init mmap_init(void);
extern void show_mem(unsigned int flags);
+extern long si_mem_available(void);
extern void si_meminfo(struct sysinfo * val);
extern void si_meminfo_node(struct sysinfo *val, int nid);
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 25a75da53c27..941b802e11ec 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3713,6 +3713,49 @@ static inline void show_node(struct zone *zone)
printk("Node %d ", zone_to_nid(zone));
}
+long si_mem_available(void)
+{
+ long available;
+ unsigned long pagecache;
+ unsigned long wmark_low = 0;
+ unsigned long pages[NR_LRU_LISTS];
+ struct zone *zone;
+ int lru;
+
+ for (lru = LRU_BASE; lru < NR_LRU_LISTS; lru++)
+ pages[lru] = global_page_state(NR_LRU_BASE + lru);
+
+ for_each_zone(zone)
+ wmark_low += zone->watermark[WMARK_LOW];
+
+ /*
+ * Estimate the amount of memory available for userspace allocations,
+ * without causing swapping.
+ */
+ available = global_page_state(NR_FREE_PAGES) - totalreserve_pages;
+
+ /*
+ * Not all the page cache can be freed, otherwise the system will
+ * start swapping. Assume at least half of the page cache, or the
+ * low watermark worth of cache, needs to stay.
+ */
+ pagecache = pages[LRU_ACTIVE_FILE] + pages[LRU_INACTIVE_FILE];
+ pagecache -= min(pagecache / 2, wmark_low);
+ available += pagecache;
+
+ /*
+ * Part of the reclaimable slab consists of items that are in use,
+ * and cannot be freed. Cap this estimate at the low watermark.
+ */
+ available += global_page_state(NR_SLAB_RECLAIMABLE) -
+ min(global_page_state(NR_SLAB_RECLAIMABLE) / 2, wmark_low);
+
+ if (available < 0)
+ available = 0;
+ return available;
+}
+EXPORT_SYMBOL_GPL(si_mem_available);
+
void si_meminfo(struct sysinfo *val)
{
val->totalram = totalram_pages;