staging: ramster: ramster-specific new files

RAMster implements peer-to-peer transcendent memory, allowing a "cluster"
of kernels to dynamically pool their RAM.

This patch adds new files necessary for ramster support:  The file
ramster.h declares externs and some pampd bitfield manipulation.  The
file zcache.h declares some zcache functions that now must be accessed
from the ramster glue code.  The file r2net.c is the glue between zcache
and the messaging layer, providing routines called from zcache that
initiate messages, and routines that handle messages by calling zcache.
TODO explains future plans for merging.

Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/ramster/TODO

@@ -0,0 +1,13 @@
+For this staging driver, RAMster duplicates code from drivers/staging/zcache
+then incorporates changes to the local copy of the code.  For V5, it also
+directly incorporates the soon-to-be-removed drivers/staging/zram/xvmalloc.[ch]
+as all testing has been done with xvmalloc rather than the new zsmalloc.
+Before RAMster can be promoted from staging, the zcache and RAMster drivers
+should be either merged or reorganized to separate out common code.
+
+Until V4, RAMster duplicated code from fs/ocfs2/cluster, but this made
+RAMster incompatible with ocfs2 running in the same kernel and included
+lots of code that could be removed.  As of V5, the ocfs2 code has been
+mined and made RAMster-specific, made to communicate with a userland
+ramster-tools package rather than ocfs2-tools, and can co-exist with ocfs2
+both in the same kernel and in userland on the same machine.

drivers/staging/ramster/r2net.c

@@ -0,0 +1,401 @@
+/*
+ * r2net.c
+ *
+ * Copyright (c) 2011, Dan Magenheimer, Oracle Corp.
+ *
+ * Ramster_r2net provides an interface between zcache and r2net.
+ *
+ * FIXME: support more than two nodes
+ */
+
+#include <linux/list.h>
+#include "cluster/tcp.h"
+#include "cluster/nodemanager.h"
+#include "tmem.h"
+#include "zcache.h"
+#include "ramster.h"
+
+#define RAMSTER_TESTING
+
+#define RMSTR_KEY	0x77347734
+
+enum {
+	RMSTR_TMEM_PUT_EPH = 100,
+	RMSTR_TMEM_PUT_PERS,
+	RMSTR_TMEM_ASYNC_GET_REQUEST,
+	RMSTR_TMEM_ASYNC_GET_AND_FREE_REQUEST,
+	RMSTR_TMEM_ASYNC_GET_REPLY,
+	RMSTR_TMEM_FLUSH,
+	RMSTR_TMEM_FLOBJ,
+	RMSTR_TMEM_DESTROY_POOL,
+};
+
+#define RMSTR_R2NET_MAX_LEN \
+		(R2NET_MAX_PAYLOAD_BYTES - sizeof(struct tmem_xhandle))
+
+#include "cluster/tcp_internal.h"
+
+static struct r2nm_node *r2net_target_node;
+static int r2net_target_nodenum;
+
+int r2net_remote_target_node_set(int node_num)
+{
+	int ret = -1;
+
+	r2net_target_node = r2nm_get_node_by_num(node_num);
+	if (r2net_target_node != NULL) {
+		r2net_target_nodenum = node_num;
+		r2nm_node_put(r2net_target_node);
+		ret = 0;
+	}
+	return ret;
+}
+
+/* FIXME following buffer should be per-cpu, protected by preempt_disable */
+static char ramster_async_get_buf[R2NET_MAX_PAYLOAD_BYTES];
+
+static int ramster_remote_async_get_request_handler(struct r2net_msg *msg,
+				u32 len, void *data, void **ret_data)
+{
+	char *pdata;
+	struct tmem_xhandle xh;
+	int found;
+	size_t size = RMSTR_R2NET_MAX_LEN;
+	u16 msgtype = be16_to_cpu(msg->msg_type);
+	bool get_and_free = (msgtype == RMSTR_TMEM_ASYNC_GET_AND_FREE_REQUEST);
+	unsigned long flags;
+
+	xh = *(struct tmem_xhandle *)msg->buf;
+	if (xh.xh_data_size > RMSTR_R2NET_MAX_LEN)
+		BUG();
+	pdata = ramster_async_get_buf;
+	*(struct tmem_xhandle *)pdata = xh;
+	pdata += sizeof(struct tmem_xhandle);
+	local_irq_save(flags);
+	found = zcache_get(xh.client_id, xh.pool_id, &xh.oid, xh.index,
+				pdata, &size, 1, get_and_free ? 1 : -1);
+	local_irq_restore(flags);
+	if (found < 0) {
+		/* a zero size indicates the get failed */
+		size = 0;
+	}
+	if (size > RMSTR_R2NET_MAX_LEN)
+		BUG();
+	*ret_data = pdata - sizeof(struct tmem_xhandle);
+	/* now make caller (r2net_process_message) handle specially */
+	r2net_force_data_magic(msg, RMSTR_TMEM_ASYNC_GET_REPLY, RMSTR_KEY);
+	return size + sizeof(struct tmem_xhandle);
+}
+
+static int ramster_remote_async_get_reply_handler(struct r2net_msg *msg,
+				u32 len, void *data, void **ret_data)
+{
+	char *in = (char *)msg->buf;
+	int datalen = len - sizeof(struct r2net_msg);
+	int ret = -1;
+	struct tmem_xhandle *xh = (struct tmem_xhandle *)in;
+
+	in += sizeof(struct tmem_xhandle);
+	datalen -= sizeof(struct tmem_xhandle);
+	BUG_ON(datalen < 0 || datalen > PAGE_SIZE);
+	ret = zcache_localify(xh->pool_id, &xh->oid, xh->index,
+				in, datalen, xh->extra);
+#ifdef RAMSTER_TESTING
+	if (ret == -EEXIST)
+		pr_err("TESTING ArrgREP, aborted overwrite on racy put\n");
+#endif
+	return ret;
+}
+
+int ramster_remote_put_handler(struct r2net_msg *msg,
+				u32 len, void *data, void **ret_data)
+{
+	struct tmem_xhandle *xh;
+	char *p = (char *)msg->buf;
+	int datalen = len - sizeof(struct r2net_msg) -
+				sizeof(struct tmem_xhandle);
+	u16 msgtype = be16_to_cpu(msg->msg_type);
+	bool ephemeral = (msgtype == RMSTR_TMEM_PUT_EPH);
+	unsigned long flags;
+	int ret;
+
+	xh = (struct tmem_xhandle *)p;
+	p += sizeof(struct tmem_xhandle);
+	zcache_autocreate_pool(xh->client_id, xh->pool_id, ephemeral);
+	local_irq_save(flags);
+	ret = zcache_put(xh->client_id, xh->pool_id, &xh->oid, xh->index,
+				p, datalen, 1, ephemeral ? 1 : -1);
+	local_irq_restore(flags);
+	return ret;
+}
+
+int ramster_remote_flush_handler(struct r2net_msg *msg,
+				u32 len, void *data, void **ret_data)
+{
+	struct tmem_xhandle *xh;
+	char *p = (char *)msg->buf;
+
+	xh = (struct tmem_xhandle *)p;
+	p += sizeof(struct tmem_xhandle);
+	(void)zcache_flush(xh->client_id, xh->pool_id, &xh->oid, xh->index);
+	return 0;
+}
+
+int ramster_remote_flobj_handler(struct r2net_msg *msg,
+				u32 len, void *data, void **ret_data)
+{
+	struct tmem_xhandle *xh;
+	char *p = (char *)msg->buf;
+
+	xh = (struct tmem_xhandle *)p;
+	p += sizeof(struct tmem_xhandle);
+	(void)zcache_flush_object(xh->client_id, xh->pool_id, &xh->oid);
+	return 0;
+}
+
+int ramster_remote_async_get(struct tmem_xhandle *xh, bool free, int remotenode,
+				size_t expect_size, uint8_t expect_cksum,
+				void *extra)
+{
+	int ret = -1, status;
+	struct r2nm_node *node = NULL;
+	struct kvec vec[1];
+	size_t veclen = 1;
+	u32 msg_type;
+
+	node = r2nm_get_node_by_num(remotenode);
+	if (node == NULL)
+		goto out;
+	xh->client_id = r2nm_this_node(); /* which node is getting */
+	xh->xh_data_cksum = expect_cksum;
+	xh->xh_data_size = expect_size;
+	xh->extra = extra;
+	vec[0].iov_len = sizeof(*xh);
+	vec[0].iov_base = xh;
+	if (free)
+		msg_type = RMSTR_TMEM_ASYNC_GET_AND_FREE_REQUEST;
+	else
+		msg_type = RMSTR_TMEM_ASYNC_GET_REQUEST;
+	ret = r2net_send_message_vec(msg_type, RMSTR_KEY,
+					vec, veclen, remotenode, &status);
+	r2nm_node_put(node);
+	if (ret < 0) {
+		/* FIXME handle bad message possibilities here? */
+		pr_err("UNTESTED ret<0 in ramster_remote_async_get\n");
+	}
+	ret = status;
+out:
+	return ret;
+}
+
+#ifdef RAMSTER_TESTING
+/* leave me here to see if it catches a weird crash */
+static void ramster_check_irq_counts(void)
+{
+	static int last_hardirq_cnt, last_softirq_cnt, last_preempt_cnt;
+	int cur_hardirq_cnt, cur_softirq_cnt, cur_preempt_cnt;
+
+	cur_hardirq_cnt = hardirq_count() >> HARDIRQ_SHIFT;
+	if (cur_hardirq_cnt > last_hardirq_cnt) {
+		last_hardirq_cnt = cur_hardirq_cnt;
+		if (!(last_hardirq_cnt&(last_hardirq_cnt-1)))
+			pr_err("RAMSTER TESTING RRP hardirq_count=%d\n",
+				last_hardirq_cnt);
+	}
+	cur_softirq_cnt = softirq_count() >> SOFTIRQ_SHIFT;
+	if (cur_softirq_cnt > last_softirq_cnt) {
+		last_softirq_cnt = cur_softirq_cnt;
+		if (!(last_softirq_cnt&(last_softirq_cnt-1)))
+			pr_err("RAMSTER TESTING RRP softirq_count=%d\n",
+				last_softirq_cnt);
+	}
+	cur_preempt_cnt = preempt_count() & PREEMPT_MASK;
+	if (cur_preempt_cnt > last_preempt_cnt) {
+		last_preempt_cnt = cur_preempt_cnt;
+		if (!(last_preempt_cnt&(last_preempt_cnt-1)))
+			pr_err("RAMSTER TESTING RRP preempt_count=%d\n",
+				last_preempt_cnt);
+	}
+}
+#endif
+
+int ramster_remote_put(struct tmem_xhandle *xh, char *data, size_t size,
+				bool ephemeral, int *remotenode)
+{
+	int nodenum, ret = -1, status;
+	struct r2nm_node *node = NULL;
+	struct kvec vec[2];
+	size_t veclen = 2;
+	u32 msg_type;
+#ifdef RAMSTER_TESTING
+	struct r2net_node *nn;
+#endif
+
+	BUG_ON(size > RMSTR_R2NET_MAX_LEN);
+	xh->client_id = r2nm_this_node(); /* which node is putting */
+	vec[0].iov_len = sizeof(*xh);
+	vec[0].iov_base = xh;
+	vec[1].iov_len = size;
+	vec[1].iov_base = data;
+	node = r2net_target_node;
+	if (!node)
+		goto out;
+
+	nodenum = r2net_target_nodenum;
+
+	r2nm_node_get(node);
+
+#ifdef RAMSTER_TESTING
+	nn = r2net_nn_from_num(nodenum);
+	WARN_ON_ONCE(nn->nn_persistent_error || !nn->nn_sc_valid);
+#endif
+
+	if (ephemeral)
+		msg_type = RMSTR_TMEM_PUT_EPH;
+	else
+		msg_type = RMSTR_TMEM_PUT_PERS;
+#ifdef RAMSTER_TESTING
+	/* leave me here to see if it catches a weird crash */
+	ramster_check_irq_counts();
+#endif
+
+	ret = r2net_send_message_vec(msg_type, RMSTR_KEY, vec, veclen,
+						nodenum, &status);
+#ifdef RAMSTER_TESTING
+	if (ret != 0) {
+		static unsigned long cnt;
+		cnt++;
+		if (!(cnt&(cnt-1)))
+			pr_err("ramster_remote_put: message failed, "
+				"ret=%d, cnt=%lu\n", ret, cnt);
+		ret = -1;
+	}
+#endif
+	if (ret < 0)
+		ret = -1;
+	else {
+		ret = status;
+		*remotenode = nodenum;
+	}
+
+	r2nm_node_put(node);
+out:
+	return ret;
+}
+
+int ramster_remote_flush(struct tmem_xhandle *xh, int remotenode)
+{
+	int ret = -1, status;
+	struct r2nm_node *node = NULL;
+	struct kvec vec[1];
+	size_t veclen = 1;
+
+	node = r2nm_get_node_by_num(remotenode);
+	BUG_ON(node == NULL);
+	xh->client_id = r2nm_this_node(); /* which node is flushing */
+	vec[0].iov_len = sizeof(*xh);
+	vec[0].iov_base = xh;
+	BUG_ON(irqs_disabled());
+	BUG_ON(in_softirq());
+	ret = r2net_send_message_vec(RMSTR_TMEM_FLUSH, RMSTR_KEY,
+					vec, veclen, remotenode, &status);
+	r2nm_node_put(node);
+	return ret;
+}
+
+int ramster_remote_flush_object(struct tmem_xhandle *xh, int remotenode)
+{
+	int ret = -1, status;
+	struct r2nm_node *node = NULL;
+	struct kvec vec[1];
+	size_t veclen = 1;
+
+	node = r2nm_get_node_by_num(remotenode);
+	BUG_ON(node == NULL);
+	xh->client_id = r2nm_this_node(); /* which node is flobjing */
+	vec[0].iov_len = sizeof(*xh);
+	vec[0].iov_base = xh;
+	ret = r2net_send_message_vec(RMSTR_TMEM_FLOBJ, RMSTR_KEY,
+					vec, veclen, remotenode, &status);
+	r2nm_node_put(node);
+	return ret;
+}
+
+/*
+ * Handler registration
+ */
+
+static LIST_HEAD(r2net_unreg_list);
+
+static void r2net_unregister_handlers(void)
+{
+	r2net_unregister_handler_list(&r2net_unreg_list);
+}
+
+int r2net_register_handlers(void)
+{
+	int status;
+
+	status = r2net_register_handler(RMSTR_TMEM_PUT_EPH, RMSTR_KEY,
+				RMSTR_R2NET_MAX_LEN,
+				ramster_remote_put_handler,
+				NULL, NULL, &r2net_unreg_list);
+	if (status)
+		goto bail;
+
+	status = r2net_register_handler(RMSTR_TMEM_PUT_PERS, RMSTR_KEY,
+				RMSTR_R2NET_MAX_LEN,
+				ramster_remote_put_handler,
+				NULL, NULL, &r2net_unreg_list);
+	if (status)
+		goto bail;
+
+	status = r2net_register_handler(RMSTR_TMEM_ASYNC_GET_REQUEST, RMSTR_KEY,
+				RMSTR_R2NET_MAX_LEN,
+				ramster_remote_async_get_request_handler,
+				NULL, NULL,
+				&r2net_unreg_list);
+	if (status)
+		goto bail;
+
+	status = r2net_register_handler(RMSTR_TMEM_ASYNC_GET_AND_FREE_REQUEST,
+				RMSTR_KEY, RMSTR_R2NET_MAX_LEN,
+				ramster_remote_async_get_request_handler,
+				NULL, NULL,
+				&r2net_unreg_list);
+	if (status)
+		goto bail;
+
+	status = r2net_register_handler(RMSTR_TMEM_ASYNC_GET_REPLY, RMSTR_KEY,
+				RMSTR_R2NET_MAX_LEN,
+				ramster_remote_async_get_reply_handler,
+				NULL, NULL,
+				&r2net_unreg_list);
+	if (status)
+		goto bail;
+
+	status = r2net_register_handler(RMSTR_TMEM_FLUSH, RMSTR_KEY,
+				RMSTR_R2NET_MAX_LEN,
+				ramster_remote_flush_handler,
+				NULL, NULL,
+				&r2net_unreg_list);
+	if (status)
+		goto bail;
+
+	status = r2net_register_handler(RMSTR_TMEM_FLOBJ, RMSTR_KEY,
+				RMSTR_R2NET_MAX_LEN,
+				ramster_remote_flobj_handler,
+				NULL, NULL,
+				&r2net_unreg_list);
+	if (status)
+		goto bail;
+
+	pr_info("ramster: r2net handlers registered\n");
+
+bail:
+	if (status) {
+		r2net_unregister_handlers();
+		pr_err("ramster: couldn't register r2net handlers\n");
+	}
+	return status;
+}

drivers/staging/ramster/ramster.h

@@ -0,0 +1,118 @@
+/*
+ * ramster.h
+ *
+ * Peer-to-peer transcendent memory
+ *
+ * Copyright (c) 2009-2012, Dan Magenheimer, Oracle Corp.
+ */
+
+#ifndef _RAMSTER_H_
+#define _RAMSTER_H_
+
+/*
+ * format of remote pampd:
+ *   bit 0 == intransit
+ *   bit 1 == is_remote... if this bit is set, then
+ *   bit 2-9 == remotenode
+ *   bit 10-22 == size
+ *   bit 23-30 == cksum
+ */
+#define FAKE_PAMPD_INTRANSIT_BITS	1
+#define FAKE_PAMPD_ISREMOTE_BITS	1
+#define FAKE_PAMPD_REMOTENODE_BITS	8
+#define FAKE_PAMPD_REMOTESIZE_BITS	13
+#define FAKE_PAMPD_CHECKSUM_BITS	8
+
+#define FAKE_PAMPD_INTRANSIT_SHIFT	0
+#define FAKE_PAMPD_ISREMOTE_SHIFT	(FAKE_PAMPD_INTRANSIT_SHIFT + \
+					 FAKE_PAMPD_INTRANSIT_BITS)
+#define FAKE_PAMPD_REMOTENODE_SHIFT	(FAKE_PAMPD_ISREMOTE_SHIFT + \
+					 FAKE_PAMPD_ISREMOTE_BITS)
+#define FAKE_PAMPD_REMOTESIZE_SHIFT	(FAKE_PAMPD_REMOTENODE_SHIFT + \
+					 FAKE_PAMPD_REMOTENODE_BITS)
+#define FAKE_PAMPD_CHECKSUM_SHIFT	(FAKE_PAMPD_REMOTESIZE_SHIFT + \
+					 FAKE_PAMPD_REMOTESIZE_BITS)
+
+#define FAKE_PAMPD_MASK(x)		((1UL << (x)) - 1)
+
+static inline void *pampd_make_remote(int remotenode, size_t size,
+					unsigned char cksum)
+{
+	unsigned long fake_pampd = 0;
+	fake_pampd |= 1UL << FAKE_PAMPD_ISREMOTE_SHIFT;
+	fake_pampd |= ((unsigned long)remotenode &
+			FAKE_PAMPD_MASK(FAKE_PAMPD_REMOTENODE_BITS)) <<
+				FAKE_PAMPD_REMOTENODE_SHIFT;
+	fake_pampd |= ((unsigned long)size &
+			FAKE_PAMPD_MASK(FAKE_PAMPD_REMOTESIZE_BITS)) <<
+				FAKE_PAMPD_REMOTESIZE_SHIFT;
+	fake_pampd |= ((unsigned long)cksum &
+			FAKE_PAMPD_MASK(FAKE_PAMPD_CHECKSUM_BITS)) <<
+				FAKE_PAMPD_CHECKSUM_SHIFT;
+	return (void *)fake_pampd;
+}
+
+static inline unsigned int pampd_remote_node(void *pampd)
+{
+	unsigned long fake_pampd = (unsigned long)pampd;
+	return (fake_pampd >> FAKE_PAMPD_REMOTENODE_SHIFT) &
+		FAKE_PAMPD_MASK(FAKE_PAMPD_REMOTENODE_BITS);
+}
+
+static inline unsigned int pampd_remote_size(void *pampd)
+{
+	unsigned long fake_pampd = (unsigned long)pampd;
+	return (fake_pampd >> FAKE_PAMPD_REMOTESIZE_SHIFT) &
+		FAKE_PAMPD_MASK(FAKE_PAMPD_REMOTESIZE_BITS);
+}
+
+static inline unsigned char pampd_remote_cksum(void *pampd)
+{
+	unsigned long fake_pampd = (unsigned long)pampd;
+	return (fake_pampd >> FAKE_PAMPD_CHECKSUM_SHIFT) &
+		FAKE_PAMPD_MASK(FAKE_PAMPD_CHECKSUM_BITS);
+}
+
+static inline bool pampd_is_remote(void *pampd)
+{
+	unsigned long fake_pampd = (unsigned long)pampd;
+	return (fake_pampd >> FAKE_PAMPD_ISREMOTE_SHIFT) &
+		FAKE_PAMPD_MASK(FAKE_PAMPD_ISREMOTE_BITS);
+}
+
+static inline bool pampd_is_intransit(void *pampd)
+{
+	unsigned long fake_pampd = (unsigned long)pampd;
+	return (fake_pampd >> FAKE_PAMPD_INTRANSIT_SHIFT) &
+		FAKE_PAMPD_MASK(FAKE_PAMPD_INTRANSIT_BITS);
+}
+
+/* note that it is a BUG for intransit to be set without isremote also set */
+static inline void *pampd_mark_intransit(void *pampd)
+{
+	unsigned long fake_pampd = (unsigned long)pampd;
+
+	fake_pampd |= 1UL << FAKE_PAMPD_ISREMOTE_SHIFT;
+	fake_pampd |= 1UL << FAKE_PAMPD_INTRANSIT_SHIFT;
+	return (void *)fake_pampd;
+}
+
+static inline void *pampd_mask_intransit_and_remote(void *marked_pampd)
+{
+	unsigned long pampd = (unsigned long)marked_pampd;
+
+	pampd &= ~(1UL << FAKE_PAMPD_INTRANSIT_SHIFT);
+	pampd &= ~(1UL << FAKE_PAMPD_ISREMOTE_SHIFT);
+	return (void *)pampd;
+}
+
+extern int ramster_remote_async_get(struct tmem_xhandle *,
+				bool, int, size_t, uint8_t, void *extra);
+extern int ramster_remote_put(struct tmem_xhandle *, char *, size_t,
+				bool, int *);
+extern int ramster_remote_flush(struct tmem_xhandle *, int);
+extern int ramster_remote_flush_object(struct tmem_xhandle *, int);
+extern int r2net_register_handlers(void);
+extern int r2net_remote_target_node_set(int);
+
+#endif /* _TMEM_H */

drivers/staging/ramster/zcache.h

@@ -0,0 +1,22 @@
+/*
+ * zcache.h
+ *
+ * External zcache functions
+ *
+ * Copyright (c) 2009-2012, Dan Magenheimer, Oracle Corp.
+ */
+
+#ifndef _ZCACHE_H_
+#define _ZCACHE_H_
+
+extern int zcache_put(int, int, struct tmem_oid *, uint32_t,
+			char *, size_t, bool, int);
+extern int zcache_autocreate_pool(int, int, bool);
+extern int zcache_get(int, int, struct tmem_oid *, uint32_t,
+			char *, size_t *, bool, int);
+extern int zcache_flush(int, int, struct tmem_oid *, uint32_t);
+extern int zcache_flush_object(int, int, struct tmem_oid *);
+extern int zcache_localify(int, struct tmem_oid *, uint32_t,
+			char *, size_t, void *);
+
+#endif /* _ZCACHE_H */