/*
* Xen implementation for transcendent memory (tmem)
*
- * Copyright (C) 2009-2010 Oracle Corp. All rights reserved.
+ * Copyright (C) 2009-2011 Oracle Corp. All rights reserved.
* Author: Dan Magenheimer
*/
#include <linux/types.h>
#include <linux/init.h>
#include <linux/pagemap.h>
+#include <linux/module.h>
#include <linux/cleancache.h>
+/* temporary ifdef until include/linux/frontswap.h is upstream */
+#ifdef CONFIG_FRONTSWAP
+#include <linux/frontswap.h>
+#endif
+
#include <xen/xen.h>
#include <xen/interface/xen.h>
#include <asm/xen/hypercall.h>
return xen_tmem_op(TMEM_FLUSH_OBJECT, pool_id, oid, 0, 0, 0, 0, 0);
}
-static int xen_tmem_destroy_pool(u32 pool_id)
-{
- struct tmem_oid oid = { { 0 } };
-
- return xen_tmem_op(TMEM_DESTROY_POOL, pool_id, oid, 0, 0, 0, 0, 0);
-}
-
-int tmem_enabled;
+int tmem_enabled __read_mostly;
+EXPORT_SYMBOL(tmem_enabled);
static int __init enable_tmem(char *s)
{
__setup("tmem", enable_tmem);
+#ifdef CONFIG_CLEANCACHE
+static int xen_tmem_destroy_pool(u32 pool_id)
+{
+ struct tmem_oid oid = { { 0 } };
+
+ return xen_tmem_op(TMEM_DESTROY_POOL, pool_id, oid, 0, 0, 0, 0, 0);
+}
+
/* cleancache ops */
static void tmem_cleancache_put_page(int pool, struct cleancache_filekey key,
.init_shared_fs = tmem_cleancache_init_shared_fs,
.init_fs = tmem_cleancache_init_fs
};
+#endif
-static int __init xen_tmem_init(void)
+#ifdef CONFIG_FRONTSWAP
+/* frontswap tmem operations */
+
+/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
+static int tmem_frontswap_poolid;
+
+/*
+ * Swizzling increases objects per swaptype, increasing tmem concurrency
+ * for heavy swaploads. Later, larger nr_cpus -> larger SWIZ_BITS
+ */
+#define SWIZ_BITS 4
+#define SWIZ_MASK ((1 << SWIZ_BITS) - 1)
+#define _oswiz(_type, _ind) ((_type << SWIZ_BITS) | (_ind & SWIZ_MASK))
+#define iswiz(_ind) (_ind >> SWIZ_BITS)
+
+static inline struct tmem_oid oswiz(unsigned type, u32 ind)
{
- struct cleancache_ops old_ops;
+ struct tmem_oid oid = { .oid = { 0 } };
+ oid.oid[0] = _oswiz(type, ind);
+ return oid;
+}
+/* returns 0 if the page was successfully put into frontswap, -1 if not */
+static int tmem_frontswap_put_page(unsigned type, pgoff_t offset,
+ struct page *page)
+{
+ u64 ind64 = (u64)offset;
+ u32 ind = (u32)offset;
+ unsigned long pfn = page_to_pfn(page);
+ int pool = tmem_frontswap_poolid;
+ int ret;
+
+ if (pool < 0)
+ return -1;
+ if (ind64 != ind)
+ return -1;
+ mb(); /* ensure page is quiescent; tmem may address it with an alias */
+ ret = xen_tmem_put_page(pool, oswiz(type, ind), iswiz(ind), pfn);
+ /* translate Xen tmem return values to linux semantics */
+ if (ret == 1)
+ return 0;
+ else
+ return -1;
+}
+
+/*
+ * returns 0 if the page was successfully gotten from frontswap, -1 if
+ * was not present (should never happen!)
+ */
+static int tmem_frontswap_get_page(unsigned type, pgoff_t offset,
+ struct page *page)
+{
+ u64 ind64 = (u64)offset;
+ u32 ind = (u32)offset;
+ unsigned long pfn = page_to_pfn(page);
+ int pool = tmem_frontswap_poolid;
+ int ret;
+
+ if (pool < 0)
+ return -1;
+ if (ind64 != ind)
+ return -1;
+ ret = xen_tmem_get_page(pool, oswiz(type, ind), iswiz(ind), pfn);
+ /* translate Xen tmem return values to linux semantics */
+ if (ret == 1)
+ return 0;
+ else
+ return -1;
+}
+
+/* flush a single page from frontswap */
+static void tmem_frontswap_flush_page(unsigned type, pgoff_t offset)
+{
+ u64 ind64 = (u64)offset;
+ u32 ind = (u32)offset;
+ int pool = tmem_frontswap_poolid;
+
+ if (pool < 0)
+ return;
+ if (ind64 != ind)
+ return;
+ (void) xen_tmem_flush_page(pool, oswiz(type, ind), iswiz(ind));
+}
+
+/* flush all pages from the passed swaptype */
+static void tmem_frontswap_flush_area(unsigned type)
+{
+ int pool = tmem_frontswap_poolid;
+ int ind;
+
+ if (pool < 0)
+ return;
+ for (ind = SWIZ_MASK; ind >= 0; ind--)
+ (void)xen_tmem_flush_object(pool, oswiz(type, ind));
+}
+
+static void tmem_frontswap_init(unsigned ignored)
+{
+ struct tmem_pool_uuid private = TMEM_POOL_PRIVATE_UUID;
+
+ /* a single tmem poolid is used for all frontswap "types" (swapfiles) */
+ if (tmem_frontswap_poolid < 0)
+ tmem_frontswap_poolid =
+ xen_tmem_new_pool(private, TMEM_POOL_PERSIST, PAGE_SIZE);
+}
+
+static int __initdata use_frontswap = 1;
+
+static int __init no_frontswap(char *s)
+{
+ use_frontswap = 0;
+ return 1;
+}
+
+__setup("nofrontswap", no_frontswap);
+
+static struct frontswap_ops tmem_frontswap_ops = {
+ .put_page = tmem_frontswap_put_page,
+ .get_page = tmem_frontswap_get_page,
+ .flush_page = tmem_frontswap_flush_page,
+ .flush_area = tmem_frontswap_flush_area,
+ .init = tmem_frontswap_init
+};
+#endif
+
+static int __init xen_tmem_init(void)
+{
if (!xen_domain())
return 0;
+#ifdef CONFIG_FRONTSWAP
+ if (tmem_enabled && use_frontswap) {
+ char *s = "";
+ struct frontswap_ops old_ops =
+ frontswap_register_ops(&tmem_frontswap_ops);
+
+ tmem_frontswap_poolid = -1;
+ if (old_ops.init != NULL)
+ s = " (WARNING: frontswap_ops overridden)";
+ printk(KERN_INFO "frontswap enabled, RAM provided by "
+ "Xen Transcendent Memory\n");
+ }
+#endif
#ifdef CONFIG_CLEANCACHE
BUG_ON(sizeof(struct cleancache_filekey) != sizeof(struct tmem_oid));
if (tmem_enabled && use_cleancache) {
char *s = "";
- old_ops = cleancache_register_ops(&tmem_cleancache_ops);
+ struct cleancache_ops old_ops =
+ cleancache_register_ops(&tmem_cleancache_ops);
if (old_ops.init_fs != NULL)
s = " (WARNING: cleancache_ops overridden)";
printk(KERN_INFO "cleancache enabled, RAM provided by "
git.openpandora.org / pandora-kernel.git / commitdiff