[CELL] spufs: extension of spu_create to support affinity definition

This patch adds support for additional flags at spu_create, which relate
to the establishment of affinity between contexts and contexts to memory.
A fourth, optional, parameter is supported. This parameter represent
a affinity neighbor of the context being created, and is used when defining
SPU-SPU affinity.
Affinity is represented as a doubly linked list of spu_contexts.

Signed-off-by: Andre Detsch <adetsch@br.ibm.com>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>

arch/powerpc/platforms/cell/spu_syscalls.c

@@ -34,14 +34,27 @@ struct spufs_calls spufs_calls = {
  * this file is not used and the syscalls directly enter the fs code */
 
 asmlinkage long sys_spu_create(const char __user *name,
-		unsigned int flags, mode_t mode)
+		unsigned int flags, mode_t mode, int neighbor_fd)
 {
 	long ret;
 	struct module *owner = spufs_calls.owner;
+	struct file *neighbor;
+	int fput_needed;
 
 	ret = -ENOSYS;
 	if (owner && try_module_get(owner)) {
-		ret = spufs_calls.create_thread(name, flags, mode);
+		if (flags & SPU_CREATE_AFFINITY_SPU) {
+			neighbor = fget_light(neighbor_fd, &fput_needed);
+			if (neighbor) {
+				ret = spufs_calls.create_thread(name, flags,
+								mode, neighbor);
+				fput_light(neighbor, fput_needed);
+			}
+		}
+		else {
+			ret = spufs_calls.create_thread(name, flags,
+							mode, NULL);
+		}
 		module_put(owner);
 	}
 	return ret;

arch/powerpc/platforms/cell/spufs/context.c

@@ -55,6 +55,7 @@ struct spu_context *alloc_spu_context(struct spu_gang *gang)
 	ctx->ops = &spu_backing_ops;
 	ctx->owner = get_task_mm(current);
 	INIT_LIST_HEAD(&ctx->rq);
+	INIT_LIST_HEAD(&ctx->aff_list);
 	if (gang)
 		spu_gang_add_ctx(gang, ctx);
 	ctx->cpus_allowed = current->cpus_allowed;

arch/powerpc/platforms/cell/spufs/gang.c

@@ -35,7 +35,9 @@ struct spu_gang *alloc_spu_gang(void)
 
 	kref_init(&gang->kref);
 	mutex_init(&gang->mutex);
+	mutex_init(&gang->aff_mutex);
 	INIT_LIST_HEAD(&gang->list);
+	INIT_LIST_HEAD(&gang->aff_list_head);
 
 out:
 	return gang;
@@ -73,6 +75,8 @@ void spu_gang_remove_ctx(struct spu_gang *gang, struct spu_context *ctx)
 {
 	mutex_lock(&gang->mutex);
 	WARN_ON(ctx->gang != gang);
+	if (!list_empty(&ctx->aff_list))
+		list_del_init(&ctx->aff_list);
 	list_del_init(&ctx->gang_list);
 	gang->contexts--;
 	mutex_unlock(&gang->mutex);

arch/powerpc/platforms/cell/spufs/inode.c

@@ -316,11 +316,107 @@ out:
 	return ret;
 }
 
-static int spufs_create_context(struct inode *inode,
-			struct dentry *dentry,
-			struct vfsmount *mnt, int flags, int mode)
+static struct spu_context *
+spufs_assert_affinity(unsigned int flags, struct spu_gang *gang,
+						struct file *filp)
+{
+	struct spu_context *tmp, *neighbor;
+	int count, node;
+	int aff_supp;
+
+	aff_supp = !list_empty(&(list_entry(cbe_spu_info[0].spus.next,
+					struct spu, cbe_list))->aff_list);
+
+	if (!aff_supp)
+		return ERR_PTR(-EINVAL);
+
+	if (flags & SPU_CREATE_GANG)
+		return ERR_PTR(-EINVAL);
+
+	if (flags & SPU_CREATE_AFFINITY_MEM &&
+	    gang->aff_ref_ctx &&
+	    gang->aff_ref_ctx->flags & SPU_CREATE_AFFINITY_MEM)
+		return ERR_PTR(-EEXIST);
+
+	if (gang->aff_flags & AFF_MERGED)
+		return ERR_PTR(-EBUSY);
+
+	neighbor = NULL;
+	if (flags & SPU_CREATE_AFFINITY_SPU) {
+		if (!filp || filp->f_op != &spufs_context_fops)
+			return ERR_PTR(-EINVAL);
+
+		neighbor = get_spu_context(
+				SPUFS_I(filp->f_dentry->d_inode)->i_ctx);
+
+		if (!list_empty(&neighbor->aff_list) && !(neighbor->aff_head) &&
+		    !list_is_last(&neighbor->aff_list, &gang->aff_list_head) &&
+		    !list_entry(neighbor->aff_list.next, struct spu_context,
+		    aff_list)->aff_head)
+			return ERR_PTR(-EEXIST);
+
+		if (gang != neighbor->gang)
+			return ERR_PTR(-EINVAL);
+
+		count = 1;
+		list_for_each_entry(tmp, &gang->aff_list_head, aff_list)
+			count++;
+		if (list_empty(&neighbor->aff_list))
+			count++;
+
+		for (node = 0; node < MAX_NUMNODES; node++) {
+			if ((cbe_spu_info[node].n_spus - atomic_read(
+				&cbe_spu_info[node].reserved_spus)) >= count)
+				break;
+		}
+
+		if (node == MAX_NUMNODES)
+			return ERR_PTR(-EEXIST);
+	}
+
+	return neighbor;
+}
+
+static void
+spufs_set_affinity(unsigned int flags, struct spu_context *ctx,
+					struct spu_context *neighbor)
+{
+	if (flags & SPU_CREATE_AFFINITY_MEM)
+		ctx->gang->aff_ref_ctx = ctx;
+
+	if (flags & SPU_CREATE_AFFINITY_SPU) {
+		if (list_empty(&neighbor->aff_list)) {
+			list_add_tail(&neighbor->aff_list,
+				&ctx->gang->aff_list_head);
+			neighbor->aff_head = 1;
+		}
+
+		if (list_is_last(&neighbor->aff_list, &ctx->gang->aff_list_head)
+		    || list_entry(neighbor->aff_list.next, struct spu_context,
+							aff_list)->aff_head) {
+			list_add(&ctx->aff_list, &neighbor->aff_list);
+		} else  {
+			list_add_tail(&ctx->aff_list, &neighbor->aff_list);
+			if (neighbor->aff_head) {
+				neighbor->aff_head = 0;
+				ctx->aff_head = 1;
+			}
+		}
+
+		if (!ctx->gang->aff_ref_ctx)
+			ctx->gang->aff_ref_ctx = ctx;
+	}
+}
+
+static int
+spufs_create_context(struct inode *inode, struct dentry *dentry,
+			struct vfsmount *mnt, int flags, int mode,
+			struct file *aff_filp)
 {
 	int ret;
+	int affinity;
+	struct spu_gang *gang;
+	struct spu_context *neighbor;
 
 	ret = -EPERM;
 	if ((flags & SPU_CREATE_NOSCHED) &&
@@ -336,9 +432,29 @@ static int spufs_create_context(struct inode *inode,
 	if ((flags & SPU_CREATE_ISOLATE) && !isolated_loader)
 		goto out_unlock;
 
+	gang = NULL;
+	neighbor = NULL;
+	affinity = flags & (SPU_CREATE_AFFINITY_MEM | SPU_CREATE_AFFINITY_SPU);
+	if (affinity) {
+		gang = SPUFS_I(inode)->i_gang;
+		ret = -EINVAL;
+		if (!gang)
+			goto out_unlock;
+		mutex_lock(&gang->aff_mutex);
+		neighbor = spufs_assert_affinity(flags, gang, aff_filp);
+		if (IS_ERR(neighbor)) {
+			ret = PTR_ERR(neighbor);
+			goto out_aff_unlock;
+		}
+	}
+
 	ret = spufs_mkdir(inode, dentry, flags, mode & S_IRWXUGO);
 	if (ret)
-		goto out_unlock;
+		goto out_aff_unlock;
+
+	if (affinity)
+		spufs_set_affinity(flags, SPUFS_I(dentry->d_inode)->i_ctx,
+								neighbor);
 
 	/*
 	 * get references for dget and mntget, will be released
@@ -352,6 +468,9 @@ static int spufs_create_context(struct inode *inode,
 		goto out;
 	}
 
+out_aff_unlock:
+	if (affinity)
+		mutex_unlock(&gang->aff_mutex);
 out_unlock:
 	mutex_unlock(&inode->i_mutex);
 out:
@@ -450,7 +569,8 @@ out:
 
 static struct file_system_type spufs_type;
 
-long spufs_create(struct nameidata *nd, unsigned int flags, mode_t mode)
+long spufs_create(struct nameidata *nd, unsigned int flags, mode_t mode,
+							struct file *filp)
 {
 	struct dentry *dentry;
 	int ret;
@@ -487,7 +607,7 @@ long spufs_create(struct nameidata *nd, unsigned int flags, mode_t mode)
 					dentry, nd->mnt, mode);
 	else
 		return spufs_create_context(nd->dentry->d_inode,
-					dentry, nd->mnt, flags, mode);
+					dentry, nd->mnt, flags, mode, filp);
 
 out_dput:
 	dput(dentry);

arch/powerpc/platforms/cell/spufs/spufs.h

@@ -109,6 +109,9 @@ struct spu_context {
 		unsigned long long class2_intr_base; /* # at last ctx switch */
 		unsigned long long libassist;
 	} stats;
+
+	struct list_head aff_list;
+	int aff_head;
 };
 
 struct spu_gang {
@@ -116,8 +119,17 @@ struct spu_gang {
 	struct mutex mutex;
 	struct kref kref;
 	int contexts;
+
+	struct spu_context *aff_ref_ctx;
+	struct list_head aff_list_head;
+	struct mutex aff_mutex;
+	int aff_flags;
 };
 
+/* Flag bits for spu_gang aff_flags */
+#define AFF_OFFSETS_SET		1
+#define AFF_MERGED		2
+
 struct mfc_dma_command {
 	int32_t pad;	/* reserved */
 	uint32_t lsa;	/* local storage address */
@@ -182,8 +194,8 @@ extern struct tree_descr spufs_dir_nosched_contents[];
 
 /* system call implementation */
 long spufs_run_spu(struct spu_context *ctx, u32 *npc, u32 *status);
-long spufs_create(struct nameidata *nd,
-			 unsigned int flags, mode_t mode);
+long spufs_create(struct nameidata *nd, unsigned int flags,
+			mode_t mode, struct file *filp);
 extern const struct file_operations spufs_context_fops;
 
 /* gang management */

arch/powerpc/platforms/cell/spufs/syscalls.c

@@ -76,8 +76,8 @@ asmlinkage long sys_spu_run(int fd, __u32 __user *unpc, __u32 __user *ustatus)
 }
 #endif
 
-asmlinkage long sys_spu_create(const char __user *pathname,
-					unsigned int flags, mode_t mode)
+asmlinkage long do_spu_create(const char __user *pathname, unsigned int flags,
+				mode_t mode, struct file *neighbor)
 {
 	char *tmp;
 	int ret;
@@ -90,7 +90,7 @@ asmlinkage long sys_spu_create(const char __user *pathname,
 		ret = path_lookup(tmp, LOOKUP_PARENT|
 				LOOKUP_OPEN|LOOKUP_CREATE, &nd);
 		if (!ret) {
-			ret = spufs_create(&nd, flags, mode);
+			ret = spufs_create(&nd, flags, mode, neighbor);
 			path_release(&nd);
 		}
 		putname(tmp);
@@ -99,8 +99,32 @@ asmlinkage long sys_spu_create(const char __user *pathname,
 	return ret;
 }
 
+#ifndef MODULE
+asmlinkage long sys_spu_create(const char __user *pathname, unsigned int flags,
+				mode_t mode, int neighbor_fd)
+{
+	int fput_needed;
+	struct file *neighbor;
+	long ret;
+
+	if (flags & SPU_CREATE_AFFINITY_SPU) {
+		ret = -EBADF;
+		neighbor = fget_light(neighbor_fd, &fput_needed);
+		if (neighbor) {
+			ret = do_spu_create(pathname, flags, mode, neighbor);
+			fput_light(neighbor, fput_needed);
+		}
+	}
+	else {
+		ret = do_spu_create(pathname, flags, mode, NULL);
+	}
+
+	return ret;
+}
+#endif
+
 struct spufs_calls spufs_calls = {
-	.create_thread = sys_spu_create,
+	.create_thread = do_spu_create,
 	.spu_run = do_spu_run,
 	.owner = THIS_MODULE,
 };

include/asm-powerpc/spu.h

@@ -196,6 +196,7 @@ extern struct cbe_spu_info cbe_spu_info[];
 
 struct spu *spu_alloc(void);
 struct spu *spu_alloc_node(int node);
+struct spu *spu_alloc_spu(struct spu *spu);
 void spu_free(struct spu *spu);
 int spu_irq_class_0_bottom(struct spu *spu);
 int spu_irq_class_1_bottom(struct spu *spu);
@@ -227,7 +228,8 @@ extern long spu_sys_callback(struct spu_syscall_block *s);
 struct file;
 extern struct spufs_calls {
 	asmlinkage long (*create_thread)(const char __user *name,
-					unsigned int flags, mode_t mode);
+					unsigned int flags, mode_t mode,
+					struct file *neighbor);
 	asmlinkage long (*spu_run)(struct file *filp, __u32 __user *unpc,
 						__u32 __user *ustatus);
 	struct module *owner;
@@ -254,8 +256,10 @@ struct spu_coredump_calls {
 #define SPU_CREATE_GANG			0x0002
 #define SPU_CREATE_NOSCHED		0x0004
 #define SPU_CREATE_ISOLATE		0x0008
+#define SPU_CREATE_AFFINITY_SPU		0x0010
+#define SPU_CREATE_AFFINITY_MEM		0x0020
 
-#define SPU_CREATE_FLAG_ALL		0x000f /* mask of all valid flags */
+#define SPU_CREATE_FLAG_ALL		0x003f /* mask of all valid flags */
 
 
 #ifdef CONFIG_SPU_FS_MODULE

include/linux/syscalls.h

@@ -549,7 +549,7 @@ asmlinkage long sys_inotify_rm_watch(int fd, u32 wd);
 asmlinkage long sys_spu_run(int fd, __u32 __user *unpc,
 				 __u32 __user *ustatus);
 asmlinkage long sys_spu_create(const char __user *name,
-		unsigned int flags, mode_t mode);
+		unsigned int flags, mode_t mode, int fd);
 
 asmlinkage long sys_mknodat(int dfd, const char __user * filename, int mode,
 			    unsigned dev);