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-rw-r--r--xen-mapcache.c29
1 files changed, 24 insertions, 5 deletions
diff --git a/xen-mapcache.c b/xen-mapcache.c
index 5b247ee092..7bcb86e4f8 100644
--- a/xen-mapcache.c
+++ b/xen-mapcache.c
@@ -40,6 +40,13 @@
#endif
#define MCACHE_BUCKET_SIZE (1UL << MCACHE_BUCKET_SHIFT)
+/* This is the size of the virtual address space reserve to QEMU that will not
+ * be use by MapCache.
+ * From empirical tests I observed that qemu use 75MB more than the
+ * max_mcache_size.
+ */
+#define NON_MCACHE_MEMORY_SIZE (80 * 1024 * 1024)
+
#define mapcache_lock() ((void)0)
#define mapcache_unlock() ((void)0)
@@ -92,15 +99,27 @@ void xen_map_cache_init(void)
QTAILQ_INIT(&mapcache->locked_entries);
mapcache->last_address_index = -1;
- getrlimit(RLIMIT_AS, &rlimit_as);
- if (rlimit_as.rlim_max < MCACHE_MAX_SIZE) {
- rlimit_as.rlim_cur = rlimit_as.rlim_max;
+ if (geteuid() == 0) {
+ rlimit_as.rlim_cur = RLIM_INFINITY;
+ rlimit_as.rlim_max = RLIM_INFINITY;
+ mapcache->max_mcache_size = MCACHE_MAX_SIZE;
} else {
- rlimit_as.rlim_cur = MCACHE_MAX_SIZE;
+ getrlimit(RLIMIT_AS, &rlimit_as);
+ rlimit_as.rlim_cur = rlimit_as.rlim_max;
+
+ if (rlimit_as.rlim_max != RLIM_INFINITY) {
+ fprintf(stderr, "Warning: QEMU's maximum size of virtual"
+ " memory is not infinity.\n");
+ }
+ if (rlimit_as.rlim_max < MCACHE_MAX_SIZE + NON_MCACHE_MEMORY_SIZE) {
+ mapcache->max_mcache_size = rlimit_as.rlim_max -
+ NON_MCACHE_MEMORY_SIZE;
+ } else {
+ mapcache->max_mcache_size = MCACHE_MAX_SIZE;
+ }
}
setrlimit(RLIMIT_AS, &rlimit_as);
- mapcache->max_mcache_size = rlimit_as.rlim_cur;
mapcache->nr_buckets =
(((mapcache->max_mcache_size >> XC_PAGE_SHIFT) +