Jan Beulich
2010-Feb-01 12:52 UTC
[Xen-devel] [PATCH] linux/balloon: fix accounting for HVM-with-PoD case
With PoD, ballooning down a guest to the target set through xenstore
based on its totalram_pages value isn''t sufficient, since that value
doesn''t include all the pages assigned to the guest. Since the delta
is static, determine it once at load time.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
--- sle11-2010-01-12.orig/drivers/xen/balloon/balloon.c 2009-08-31
11:48:33.000000000 +0200
+++ sle11-2010-01-12/drivers/xen/balloon/balloon.c 2010-02-01 13:35:47.000000000
+0100
@@ -90,6 +90,18 @@ static unsigned long frame_list[PAGE_SIZ
#define dec_totalhigh_pages() ((void)0)
#endif
+#ifndef CONFIG_XEN
+/*
+ * In HVM guests accounting here uses the Xen visible values, but the kernel
+ * determined totalram_pages value shouldn''t get altered. Since
totalram_pages
+ * includes neither the kernel static image nor any memory allocated prior to
+ * or from the bootmem allocator, we have to synchronize the two values.
+ */
+static unsigned long __read_mostly totalram_bias;
+#else
+#define totalram_bias 0
+#endif
+
/* List of ballooned pages, threaded through the mem_map array. */
static LIST_HEAD(ballooned_pages);
@@ -305,7 +317,7 @@ static int increase_reservation(unsigned
}
bs.current_pages += rc;
- totalram_pages = bs.current_pages;
+ totalram_pages = bs.current_pages - totalram_bias;
out:
balloon_unlock(flags);
@@ -385,7 +397,7 @@ static int decrease_reservation(unsigned
BUG_ON(ret != nr_pages);
bs.current_pages -= nr_pages;
- totalram_pages = bs.current_pages;
+ totalram_pages = bs.current_pages - totalram_bias;
balloon_unlock(flags);
@@ -524,7 +536,19 @@ static struct notifier_block xenstore_no
static int __init balloon_init(void)
{
-#if defined(CONFIG_X86) && defined(CONFIG_XEN)
+#if !defined(CONFIG_XEN)
+# ifndef XENMEM_get_pod_target
+# define XENMEM_get_pod_target 17
+ typedef struct xen_pod_target {
+ uint64_t target_pages;
+ uint64_t tot_pages;
+ uint64_t pod_cache_pages;
+ uint64_t pod_entries;
+ domid_t domid;
+ } xen_pod_target_t;
+# endif
+ xen_pod_target_t pod_target = { .domid = DOMID_SELF };
+#elif defined(CONFIG_X86)
unsigned long pfn;
struct page *page;
#endif
@@ -538,7 +562,20 @@ static int __init balloon_init(void)
bs.current_pages = min(xen_start_info->nr_pages, max_pfn);
totalram_pages = bs.current_pages;
#else
- bs.current_pages = totalram_pages;
+ totalram_bias = HYPERVISOR_memory_op(
+ HYPERVISOR_memory_op(XENMEM_get_pod_target,
+ &pod_target) != -ENOSYS
+ ? XENMEM_maximum_reservation
+ : XENMEM_current_reservation,
+ &pod_target.domid);
+ if ((long)totalram_bias != -ENOSYS) {
+ BUG_ON(totalram_bias < totalram_pages);
+ bs.current_pages = totalram_bias;
+ totalram_bias -= totalram_pages;
+ } else {
+ totalram_bias = 0;
+ bs.current_pages = totalram_pages;
+ }
#endif
bs.target_pages = bs.current_pages;
bs.balloon_low = 0;
@@ -671,7 +708,7 @@ struct page **alloc_empty_pages_and_page
goto err;
}
- totalram_pages = --bs.current_pages;
+ totalram_pages = --bs.current_pages - totalram_bias;
balloon_unlock(flags);
}
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