Initial import

1 files changed, 428 insertions, 0 deletions

diff --git a/drivers/xen/tmem.c b/drivers/xen/tmem.c
new file mode 100644
index 000000000..c4211a316
--- /dev/null
+++ b/drivers/xen/tmem.c
@@ -0,0 +1,428 @@
+/*
+ * Xen implementation for transcendent memory (tmem)
+ *
+ * Copyright (C) 2009-2011 Oracle Corp.  All rights reserved.
+ * Author: Dan Magenheimer
+ */
+
+#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/pagemap.h>
+#include <linux/cleancache.h>
+#include <linux/frontswap.h>
+
+#include <xen/xen.h>
+#include <xen/interface/xen.h>
+#include <asm/xen/hypercall.h>
+#include <asm/xen/page.h>
+#include <asm/xen/hypervisor.h>
+#include <xen/tmem.h>
+
+#ifndef CONFIG_XEN_TMEM_MODULE
+bool __read_mostly tmem_enabled = false;
+
+static int __init enable_tmem(char *s)
+{
+	tmem_enabled = true;
+	return 1;
+}
+__setup("tmem", enable_tmem);
+#endif
+
+#ifdef CONFIG_CLEANCACHE
+static bool cleancache __read_mostly = true;
+module_param(cleancache, bool, S_IRUGO);
+static bool selfballooning __read_mostly = true;
+module_param(selfballooning, bool, S_IRUGO);
+#endif /* CONFIG_CLEANCACHE */
+
+#ifdef CONFIG_FRONTSWAP
+static bool frontswap __read_mostly = true;
+module_param(frontswap, bool, S_IRUGO);
+#else /* CONFIG_FRONTSWAP */
+#define frontswap (0)
+#endif /* CONFIG_FRONTSWAP */
+
+#ifdef CONFIG_XEN_SELFBALLOONING
+static bool selfshrinking __read_mostly = true;
+module_param(selfshrinking, bool, S_IRUGO);
+#endif /* CONFIG_XEN_SELFBALLOONING */
+
+#define TMEM_CONTROL               0
+#define TMEM_NEW_POOL              1
+#define TMEM_DESTROY_POOL          2
+#define TMEM_NEW_PAGE              3
+#define TMEM_PUT_PAGE              4
+#define TMEM_GET_PAGE              5
+#define TMEM_FLUSH_PAGE            6
+#define TMEM_FLUSH_OBJECT          7
+#define TMEM_READ                  8
+#define TMEM_WRITE                 9
+#define TMEM_XCHG                 10
+
+/* Bits for HYPERVISOR_tmem_op(TMEM_NEW_POOL) */
+#define TMEM_POOL_PERSIST          1
+#define TMEM_POOL_SHARED           2
+#define TMEM_POOL_PAGESIZE_SHIFT   4
+#define TMEM_VERSION_SHIFT        24
+
+
+struct tmem_pool_uuid {
+	u64 uuid_lo;
+	u64 uuid_hi;
+};
+
+struct tmem_oid {
+	u64 oid[3];
+};
+
+#define TMEM_POOL_PRIVATE_UUID	{ 0, 0 }
+
+/* flags for tmem_ops.new_pool */
+#define TMEM_POOL_PERSIST          1
+#define TMEM_POOL_SHARED           2
+
+/* xen tmem foundation ops/hypercalls */
+
+static inline int xen_tmem_op(u32 tmem_cmd, u32 tmem_pool, struct tmem_oid oid,
+	u32 index, unsigned long gmfn, u32 tmem_offset, u32 pfn_offset, u32 len)
+{
+	struct tmem_op op;
+	int rc = 0;
+
+	op.cmd = tmem_cmd;
+	op.pool_id = tmem_pool;
+	op.u.gen.oid[0] = oid.oid[0];
+	op.u.gen.oid[1] = oid.oid[1];
+	op.u.gen.oid[2] = oid.oid[2];
+	op.u.gen.index = index;
+	op.u.gen.tmem_offset = tmem_offset;
+	op.u.gen.pfn_offset = pfn_offset;
+	op.u.gen.len = len;
+	set_xen_guest_handle(op.u.gen.gmfn, (void *)gmfn);
+	rc = HYPERVISOR_tmem_op(&op);
+	return rc;
+}
+
+static int xen_tmem_new_pool(struct tmem_pool_uuid uuid,
+				u32 flags, unsigned long pagesize)
+{
+	struct tmem_op op;
+	int rc = 0, pageshift;
+
+	for (pageshift = 0; pagesize != 1; pageshift++)
+		pagesize >>= 1;
+	flags |= (pageshift - 12) << TMEM_POOL_PAGESIZE_SHIFT;
+	flags |= TMEM_SPEC_VERSION << TMEM_VERSION_SHIFT;
+	op.cmd = TMEM_NEW_POOL;
+	op.u.new.uuid[0] = uuid.uuid_lo;
+	op.u.new.uuid[1] = uuid.uuid_hi;
+	op.u.new.flags = flags;
+	rc = HYPERVISOR_tmem_op(&op);
+	return rc;
+}
+
+/* xen generic tmem ops */
+
+static int xen_tmem_put_page(u32 pool_id, struct tmem_oid oid,
+			     u32 index, unsigned long pfn)
+{
+	unsigned long gmfn = xen_pv_domain() ? pfn_to_mfn(pfn) : pfn;
+
+	return xen_tmem_op(TMEM_PUT_PAGE, pool_id, oid, index,
+		gmfn, 0, 0, 0);
+}
+
+static int xen_tmem_get_page(u32 pool_id, struct tmem_oid oid,
+			     u32 index, unsigned long pfn)
+{
+	unsigned long gmfn = xen_pv_domain() ? pfn_to_mfn(pfn) : pfn;
+
+	return xen_tmem_op(TMEM_GET_PAGE, pool_id, oid, index,
+		gmfn, 0, 0, 0);
+}
+
+static int xen_tmem_flush_page(u32 pool_id, struct tmem_oid oid, u32 index)
+{
+	return xen_tmem_op(TMEM_FLUSH_PAGE, pool_id, oid, index,
+		0, 0, 0, 0);
+}
+
+static int xen_tmem_flush_object(u32 pool_id, struct tmem_oid oid)
+{
+	return xen_tmem_op(TMEM_FLUSH_OBJECT, pool_id, oid, 0, 0, 0, 0, 0);
+}
+
+
+#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,
+				     pgoff_t index, struct page *page)
+{
+	u32 ind = (u32) index;
+	struct tmem_oid oid = *(struct tmem_oid *)&key;
+	unsigned long pfn = page_to_pfn(page);
+
+	if (pool < 0)
+		return;
+	if (ind != index)
+		return;
+	mb(); /* ensure page is quiescent; tmem may address it with an alias */
+	(void)xen_tmem_put_page((u32)pool, oid, ind, pfn);
+}
+
+static int tmem_cleancache_get_page(int pool, struct cleancache_filekey key,
+				    pgoff_t index, struct page *page)
+{
+	u32 ind = (u32) index;
+	struct tmem_oid oid = *(struct tmem_oid *)&key;
+	unsigned long pfn = page_to_pfn(page);
+	int ret;
+
+	/* translate return values to linux semantics */
+	if (pool < 0)
+		return -1;
+	if (ind != index)
+		return -1;
+	ret = xen_tmem_get_page((u32)pool, oid, ind, pfn);
+	if (ret == 1)
+		return 0;
+	else
+		return -1;
+}
+
+static void tmem_cleancache_flush_page(int pool, struct cleancache_filekey key,
+				       pgoff_t index)
+{
+	u32 ind = (u32) index;
+	struct tmem_oid oid = *(struct tmem_oid *)&key;
+
+	if (pool < 0)
+		return;
+	if (ind != index)
+		return;
+	(void)xen_tmem_flush_page((u32)pool, oid, ind);
+}
+
+static void tmem_cleancache_flush_inode(int pool, struct cleancache_filekey key)
+{
+	struct tmem_oid oid = *(struct tmem_oid *)&key;
+
+	if (pool < 0)
+		return;
+	(void)xen_tmem_flush_object((u32)pool, oid);
+}
+
+static void tmem_cleancache_flush_fs(int pool)
+{
+	if (pool < 0)
+		return;
+	(void)xen_tmem_destroy_pool((u32)pool);
+}
+
+static int tmem_cleancache_init_fs(size_t pagesize)
+{
+	struct tmem_pool_uuid uuid_private = TMEM_POOL_PRIVATE_UUID;
+
+	return xen_tmem_new_pool(uuid_private, 0, pagesize);
+}
+
+static int tmem_cleancache_init_shared_fs(char *uuid, size_t pagesize)
+{
+	struct tmem_pool_uuid shared_uuid;
+
+	shared_uuid.uuid_lo = *(u64 *)uuid;
+	shared_uuid.uuid_hi = *(u64 *)(&uuid[8]);
+	return xen_tmem_new_pool(shared_uuid, TMEM_POOL_SHARED, pagesize);
+}
+
+static struct cleancache_ops tmem_cleancache_ops = {
+	.put_page = tmem_cleancache_put_page,
+	.get_page = tmem_cleancache_get_page,
+	.invalidate_page = tmem_cleancache_flush_page,
+	.invalidate_inode = tmem_cleancache_flush_inode,
+	.invalidate_fs = tmem_cleancache_flush_fs,
+	.init_shared_fs = tmem_cleancache_init_shared_fs,
+	.init_fs = tmem_cleancache_init_fs
+};
+#endif
+
+#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 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_store(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_load(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 struct frontswap_ops tmem_frontswap_ops = {
+	.store = tmem_frontswap_store,
+	.load = tmem_frontswap_load,
+	.invalidate_page = tmem_frontswap_flush_page,
+	.invalidate_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 && frontswap) {
+		char *s = "";
+		struct frontswap_ops *old_ops;
+
+		tmem_frontswap_poolid = -1;
+		old_ops = frontswap_register_ops(&tmem_frontswap_ops);
+		if (IS_ERR(old_ops) || old_ops) {
+			if (IS_ERR(old_ops))
+				return PTR_ERR(old_ops);
+			s = " (WARNING: frontswap_ops overridden)";
+		}
+		pr_info("frontswap enabled, RAM provided by Xen Transcendent Memory%s\n",
+			s);
+	}
+#endif
+#ifdef CONFIG_CLEANCACHE
+	BUG_ON(sizeof(struct cleancache_filekey) != sizeof(struct tmem_oid));
+	if (tmem_enabled && cleancache) {
+		int err;
+
+		err = cleancache_register_ops(&tmem_cleancache_ops);
+		if (err)
+			pr_warn("xen-tmem: failed to enable cleancache: %d\n",
+				err);
+		else
+			pr_info("cleancache enabled, RAM provided by "
+				"Xen Transcendent Memory\n");
+	}
+#endif
+#ifdef CONFIG_XEN_SELFBALLOONING
+	/*
+	 * There is no point of driving pages to the swap system if they
+	 * aren't going anywhere in tmem universe.
+	 */
+	if (!frontswap) {
+		selfshrinking = false;
+		selfballooning = false;
+	}
+	xen_selfballoon_init(selfballooning, selfshrinking);
+#endif
+	return 0;
+}
+
+module_init(xen_tmem_init)
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Dan Magenheimer <dan.magenheimer@oracle.com>");
+MODULE_DESCRIPTION("Shim to Xen transcendent memory");