# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1266256444 0
# Node ID 3a0bd7ca6b1146e2165e245cb0d4c2872771de17
# Parent cbb147631e8cda24fda36d8ab627e0d9f21c4547
When tmem is enabled, reserve a fraction of memory
for allocations of 0<order<9 to avoid fragmentation
issues.
Signed-off by: Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>
---
xen/common/page_alloc.c | 19 ++++++++++++++++++-
1 files changed, 18 insertions(+), 1 deletion(-)
diff -r cbb147631e8c -r 3a0bd7ca6b11 xen/common/page_alloc.c
--- a/xen/common/page_alloc.c Mon Feb 15 17:49:14 2010 +0000
+++ b/xen/common/page_alloc.c Mon Feb 15 17:54:04 2010 +0000
@@ -224,6 +224,10 @@ static unsigned long *avail[MAX_NUMNODES
static unsigned long *avail[MAX_NUMNODES];
static long total_avail_pages;
+/* TMEM: Reserve a fraction of memory for mid-size (0<order<9) allocations.*/
+static long midsize_alloc_zone_pages;
+#define MIDSIZE_ALLOC_FRAC 128
+
static DEFINE_SPINLOCK(heap_lock);
static unsigned long init_node_heap(int node, unsigned long mfn,
@@ -304,6 +308,14 @@ static struct page_info *alloc_heap_page
spin_lock(&heap_lock);
/*
+ * TMEM: When available memory is scarce, allow only mid-size allocations
+ * to avoid worst of fragmentation issues.
+ */
+ if ( opt_tmem && ((order == 0) || (order >= 9)) &&
+ (total_avail_pages <= midsize_alloc_zone_pages) )
+ goto fail;
+
+ /*
* Start with requested node, but exhaust all node memory in requested
* zone before failing, only calc new node value if we fail to find memory
* in target node, this avoids needless computation on fast-path.
@@ -336,6 +348,7 @@ static struct page_info *alloc_heap_page
return pg;
}
+ fail:
/* No suitable memory blocks. Fail the request. */
spin_unlock(&heap_lock);
return NULL;
@@ -504,6 +517,10 @@ static void free_heap_pages(
avail[node][zone] += 1 << order;
total_avail_pages += 1 << order;
+ if ( opt_tmem )
+ midsize_alloc_zone_pages = max(
+ midsize_alloc_zone_pages, total_avail_pages / MIDSIZE_ALLOC_FRAC);
+
/* Merge chunks as far as possible. */
while ( order < MAX_ORDER )
{
@@ -842,7 +859,7 @@ static unsigned long avail_heap_pages(
unsigned long total_free_pages(void)
{
- return total_avail_pages;
+ return total_avail_pages - midsize_alloc_zone_pages;
}
void __init end_boot_allocator(void)
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