From: Arnd Bergmann Date: Wed, 4 Oct 2006 15:26:15 +0000 (+0200) Subject: [POWERPC] spufs: Add infrastructure needed for gang scheduling X-Git-Tag: v2.6.19-rc1~3^2~9 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6263203ed6e9ff107129a1ebe613290b342a4465;p=linux-2.6 [POWERPC] spufs: Add infrastructure needed for gang scheduling Add the concept of a gang to spufs as a new type of object. So far, this has no impact whatsover on scheduling, but makes it possible to add that later. A new type of object in spufs is now a spu_gang. It is created with the spu_create system call with the flags argument set to SPU_CREATE_GANG (0x2). Inside of a spu_gang, it is then possible to create spu_context objects, which until now was only possible at the root of spufs. There is a new member in struct spu_context pointing to the spu_gang it belongs to, if any. The spu_gang maintains a list of spu_context structures that are its children. This information can then be used in the scheduler in the future. There is still a bug that needs to be resolved in this basic infrastructure regarding the order in which objects are removed. When the spu_gang file descriptor is closed before the spu_context descriptors, we leak the dentry and inode for the gang. Any ideas how to cleanly solve this are appreciated. Signed-off-by: Arnd Bergmann Signed-off-by: Paul Mackerras --- diff --git a/arch/powerpc/platforms/cell/spufs/Makefile b/arch/powerpc/platforms/cell/spufs/Makefile index bb5dc63427..ecdfbb35f8 100644 --- a/arch/powerpc/platforms/cell/spufs/Makefile +++ b/arch/powerpc/platforms/cell/spufs/Makefile @@ -2,7 +2,7 @@ obj-y += switch.o obj-$(CONFIG_SPU_FS) += spufs.o spufs-y += inode.o file.o context.o syscalls.o -spufs-y += sched.o backing_ops.o hw_ops.o run.o +spufs-y += sched.o backing_ops.o hw_ops.o run.o gang.o # Rules to build switch.o with the help of SPU tool chain SPU_CROSS := spu- diff --git a/arch/powerpc/platforms/cell/spufs/context.c b/arch/powerpc/platforms/cell/spufs/context.c index 36439c5e9f..034cf6af53 100644 --- a/arch/powerpc/platforms/cell/spufs/context.c +++ b/arch/powerpc/platforms/cell/spufs/context.c @@ -27,7 +27,7 @@ #include #include "spufs.h" -struct spu_context *alloc_spu_context(void) +struct spu_context *alloc_spu_context(struct spu_gang *gang) { struct spu_context *ctx; ctx = kzalloc(sizeof *ctx, GFP_KERNEL); @@ -51,6 +51,8 @@ struct spu_context *alloc_spu_context(void) ctx->state = SPU_STATE_SAVED; ctx->ops = &spu_backing_ops; ctx->owner = get_task_mm(current); + if (gang) + spu_gang_add_ctx(gang, ctx); goto out; out_free: kfree(ctx); @@ -67,6 +69,8 @@ void destroy_spu_context(struct kref *kref) spu_deactivate(ctx); up_write(&ctx->state_sema); spu_fini_csa(&ctx->csa); + if (ctx->gang) + spu_gang_remove_ctx(ctx->gang, ctx); kfree(ctx); } diff --git a/arch/powerpc/platforms/cell/spufs/gang.c b/arch/powerpc/platforms/cell/spufs/gang.c new file mode 100644 index 0000000000..212ea78f90 --- /dev/null +++ b/arch/powerpc/platforms/cell/spufs/gang.c @@ -0,0 +1,81 @@ +/* + * SPU file system + * + * (C) Copyright IBM Deutschland Entwicklung GmbH 2005 + * + * Author: Arnd Bergmann + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2, or (at your option) + * any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#include +#include + +#include "spufs.h" + +struct spu_gang *alloc_spu_gang(void) +{ + struct spu_gang *gang; + + gang = kzalloc(sizeof *gang, GFP_KERNEL); + if (!gang) + goto out; + + kref_init(&gang->kref); + mutex_init(&gang->mutex); + INIT_LIST_HEAD(&gang->list); + +out: + return gang; +} + +static void destroy_spu_gang(struct kref *kref) +{ + struct spu_gang *gang; + gang = container_of(kref, struct spu_gang, kref); + WARN_ON(gang->contexts || !list_empty(&gang->list)); + kfree(gang); +} + +struct spu_gang *get_spu_gang(struct spu_gang *gang) +{ + kref_get(&gang->kref); + return gang; +} + +int put_spu_gang(struct spu_gang *gang) +{ + return kref_put(&gang->kref, &destroy_spu_gang); +} + +void spu_gang_add_ctx(struct spu_gang *gang, struct spu_context *ctx) +{ + mutex_lock(&gang->mutex); + ctx->gang = get_spu_gang(gang); + list_add(&ctx->gang_list, &gang->list); + gang->contexts++; + mutex_unlock(&gang->mutex); +} + +void spu_gang_remove_ctx(struct spu_gang *gang, struct spu_context *ctx) +{ + mutex_lock(&gang->mutex); + WARN_ON(ctx->gang != gang); + list_del_init(&ctx->gang_list); + gang->contexts--; + mutex_unlock(&gang->mutex); + + put_spu_gang(gang); +} diff --git a/arch/powerpc/platforms/cell/spufs/inode.c b/arch/powerpc/platforms/cell/spufs/inode.c index 8cc615ff36..427d00a4f6 100644 --- a/arch/powerpc/platforms/cell/spufs/inode.c +++ b/arch/powerpc/platforms/cell/spufs/inode.c @@ -50,6 +50,10 @@ spufs_alloc_inode(struct super_block *sb) ei = kmem_cache_alloc(spufs_inode_cache, SLAB_KERNEL); if (!ei) return NULL; + + ei->i_gang = NULL; + ei->i_ctx = NULL; + return &ei->vfs_inode; } @@ -128,14 +132,19 @@ out: static void spufs_delete_inode(struct inode *inode) { - if (SPUFS_I(inode)->i_ctx) - put_spu_context(SPUFS_I(inode)->i_ctx); + struct spufs_inode_info *ei = SPUFS_I(inode); + + if (ei->i_ctx) + put_spu_context(ei->i_ctx); + if (ei->i_gang) + put_spu_gang(ei->i_gang); clear_inode(inode); } static void spufs_prune_dir(struct dentry *dir) { struct dentry *dentry, *tmp; + mutex_lock(&dir->d_inode->i_mutex); list_for_each_entry_safe(dentry, tmp, &dir->d_subdirs, d_u.d_child) { spin_lock(&dcache_lock); @@ -156,13 +165,13 @@ static void spufs_prune_dir(struct dentry *dir) mutex_unlock(&dir->d_inode->i_mutex); } -/* Caller must hold root->i_mutex */ -static int spufs_rmdir(struct inode *root, struct dentry *dir_dentry) +/* Caller must hold parent->i_mutex */ +static int spufs_rmdir(struct inode *parent, struct dentry *dir) { /* remove all entries */ - spufs_prune_dir(dir_dentry); + spufs_prune_dir(dir); - return simple_rmdir(root, dir_dentry); + return simple_rmdir(parent, dir); } static int spufs_fill_dir(struct dentry *dir, struct tree_descr *files, @@ -191,17 +200,17 @@ out: static int spufs_dir_close(struct inode *inode, struct file *file) { struct spu_context *ctx; - struct inode *dir; - struct dentry *dentry; + struct inode *parent; + struct dentry *dir; int ret; - dentry = file->f_dentry; - dir = dentry->d_parent->d_inode; - ctx = SPUFS_I(dentry->d_inode)->i_ctx; + dir = file->f_dentry; + parent = dir->d_parent->d_inode; + ctx = SPUFS_I(dir->d_inode)->i_ctx; - mutex_lock(&dir->i_mutex); - ret = spufs_rmdir(dir, dentry); - mutex_unlock(&dir->i_mutex); + mutex_lock(&parent->i_mutex); + ret = spufs_rmdir(parent, dir); + mutex_unlock(&parent->i_mutex); WARN_ON(ret); /* We have to give up the mm_struct */ @@ -240,7 +249,7 @@ spufs_mkdir(struct inode *dir, struct dentry *dentry, unsigned int flags, inode->i_gid = dir->i_gid; inode->i_mode &= S_ISGID; } - ctx = alloc_spu_context(); + ctx = alloc_spu_context(SPUFS_I(dir)->i_gang); /* XXX gang */ SPUFS_I(inode)->i_ctx = ctx; if (!ctx) goto out_iput; @@ -292,24 +301,177 @@ out: return ret; } +static int spufs_create_context(struct inode *inode, + struct dentry *dentry, + struct vfsmount *mnt, int flags, int mode) +{ + int ret; + + ret = spufs_mkdir(inode, dentry, flags, mode & S_IRWXUGO); + if (ret) + goto out_unlock; + + /* + * get references for dget and mntget, will be released + * in error path of *_open(). + */ + ret = spufs_context_open(dget(dentry), mntget(mnt)); + if (ret < 0) { + WARN_ON(spufs_rmdir(inode, dentry)); + mutex_unlock(&inode->i_mutex); + spu_forget(SPUFS_I(dentry->d_inode)->i_ctx); + goto out; + } + +out_unlock: + mutex_unlock(&inode->i_mutex); +out: + dput(dentry); + return ret; +} + +static int spufs_rmgang(struct inode *root, struct dentry *dir) +{ + /* FIXME: this fails if the dir is not empty, + which causes a leak of gangs. */ + return simple_rmdir(root, dir); +} + +static int spufs_gang_close(struct inode *inode, struct file *file) +{ + struct inode *parent; + struct dentry *dir; + int ret; + + dir = file->f_dentry; + parent = dir->d_parent->d_inode; + + ret = spufs_rmgang(parent, dir); + WARN_ON(ret); + + return dcache_dir_close(inode, file); +} + +struct file_operations spufs_gang_fops = { + .open = dcache_dir_open, + .release = spufs_gang_close, + .llseek = dcache_dir_lseek, + .read = generic_read_dir, + .readdir = dcache_readdir, + .fsync = simple_sync_file, +}; + +static int +spufs_mkgang(struct inode *dir, struct dentry *dentry, int mode) +{ + int ret; + struct inode *inode; + struct spu_gang *gang; + + ret = -ENOSPC; + inode = spufs_new_inode(dir->i_sb, mode | S_IFDIR); + if (!inode) + goto out; + + ret = 0; + if (dir->i_mode & S_ISGID) { + inode->i_gid = dir->i_gid; + inode->i_mode &= S_ISGID; + } + gang = alloc_spu_gang(); + SPUFS_I(inode)->i_ctx = NULL; + SPUFS_I(inode)->i_gang = gang; + if (!gang) + goto out_iput; + + inode->i_op = &spufs_dir_inode_operations; + inode->i_fop = &simple_dir_operations; + + d_instantiate(dentry, inode); + dget(dentry); + dir->i_nlink++; + dentry->d_inode->i_nlink++; + return ret; + +out_iput: + iput(inode); +out: + return ret; +} + +static int spufs_gang_open(struct dentry *dentry, struct vfsmount *mnt) +{ + int ret; + struct file *filp; + + ret = get_unused_fd(); + if (ret < 0) { + dput(dentry); + mntput(mnt); + goto out; + } + + filp = dentry_open(dentry, mnt, O_RDONLY); + if (IS_ERR(filp)) { + put_unused_fd(ret); + ret = PTR_ERR(filp); + goto out; + } + + filp->f_op = &spufs_gang_fops; + fd_install(ret, filp); +out: + return ret; +} + +static int spufs_create_gang(struct inode *inode, + struct dentry *dentry, + struct vfsmount *mnt, int mode) +{ + int ret; + + ret = spufs_mkgang(inode, dentry, mode & S_IRWXUGO); + if (ret) + goto out; + + /* + * get references for dget and mntget, will be released + * in error path of *_open(). + */ + ret = spufs_gang_open(dget(dentry), mntget(mnt)); + if (ret < 0) + WARN_ON(spufs_rmgang(inode, dentry)); + +out: + mutex_unlock(&inode->i_mutex); + dput(dentry); + return ret; +} + + static struct file_system_type spufs_type; -long spufs_create_thread(struct nameidata *nd, - unsigned int flags, mode_t mode) +long spufs_create(struct nameidata *nd, unsigned int flags, mode_t mode) { struct dentry *dentry; int ret; - /* need to be at the root of spufs */ ret = -EINVAL; - if (nd->dentry->d_sb->s_type != &spufs_type || - nd->dentry != nd->dentry->d_sb->s_root) + /* check if we are on spufs */ + if (nd->dentry->d_sb->s_type != &spufs_type) goto out; - /* all flags are reserved */ + /* don't accept undefined flags */ if (flags & (~SPU_CREATE_FLAG_ALL)) goto out; + /* only threads can be underneath a gang */ + if (nd->dentry != nd->dentry->d_sb->s_root) { + if ((flags & SPU_CREATE_GANG) || + !SPUFS_I(nd->dentry->d_inode)->i_gang) + goto out; + } + dentry = lookup_create(nd, 1); ret = PTR_ERR(dentry); if (IS_ERR(dentry)) @@ -320,22 +482,13 @@ long spufs_create_thread(struct nameidata *nd, goto out_dput; mode &= ~current->fs->umask; - ret = spufs_mkdir(nd->dentry->d_inode, dentry, flags, mode & S_IRWXUGO); - if (ret) - goto out_dput; - /* - * get references for dget and mntget, will be released - * in error path of *_open(). - */ - ret = spufs_context_open(dget(dentry), mntget(nd->mnt)); - if (ret < 0) { - WARN_ON(spufs_rmdir(nd->dentry->d_inode, dentry)); - mutex_unlock(&nd->dentry->d_inode->i_mutex); - spu_forget(SPUFS_I(dentry->d_inode)->i_ctx); - dput(dentry); - goto out; - } + if (flags & SPU_CREATE_GANG) + return spufs_create_gang(nd->dentry->d_inode, + dentry, nd->mnt, mode); + else + return spufs_create_context(nd->dentry->d_inode, + dentry, nd->mnt, flags, mode); out_dput: dput(dentry); diff --git a/arch/powerpc/platforms/cell/spufs/spufs.h b/arch/powerpc/platforms/cell/spufs/spufs.h index 2fb6a00991..f6624ceedf 100644 --- a/arch/powerpc/platforms/cell/spufs/spufs.h +++ b/arch/powerpc/platforms/cell/spufs/spufs.h @@ -39,6 +39,8 @@ struct spu_context_ops; #define SPU_CONTEXT_PREEMPT 0UL +struct spu_gang; + struct spu_context { struct spu *spu; /* pointer to a physical SPU */ struct spu_state csa; /* SPU context save area. */ @@ -68,6 +70,16 @@ struct spu_context { struct work_struct reap_work; unsigned long flags; unsigned long event_return; + + struct list_head gang_list; + struct spu_gang *gang; +}; + +struct spu_gang { + struct list_head list; + struct mutex mutex; + struct kref kref; + int contexts; }; struct mfc_dma_command { @@ -115,6 +127,7 @@ extern struct spu_context_ops spu_backing_ops; struct spufs_inode_info { struct spu_context *i_ctx; + struct spu_gang *i_gang; struct inode vfs_inode; }; #define SPUFS_I(inode) \ @@ -125,12 +138,19 @@ extern struct tree_descr spufs_dir_contents[]; /* system call implementation */ long spufs_run_spu(struct file *file, struct spu_context *ctx, u32 *npc, u32 *status); -long spufs_create_thread(struct nameidata *nd, +long spufs_create(struct nameidata *nd, unsigned int flags, mode_t mode); extern struct file_operations spufs_context_fops; +/* gang management */ +struct spu_gang *alloc_spu_gang(void); +struct spu_gang *get_spu_gang(struct spu_gang *gang); +int put_spu_gang(struct spu_gang *gang); +void spu_gang_remove_ctx(struct spu_gang *gang, struct spu_context *ctx); +void spu_gang_add_ctx(struct spu_gang *gang, struct spu_context *ctx); + /* context management */ -struct spu_context * alloc_spu_context(void); +struct spu_context * alloc_spu_context(struct spu_gang *gang); void destroy_spu_context(struct kref *kref); struct spu_context * get_spu_context(struct spu_context *ctx); int put_spu_context(struct spu_context *ctx); diff --git a/arch/powerpc/platforms/cell/spufs/syscalls.c b/arch/powerpc/platforms/cell/spufs/syscalls.c index ef33a0ca20..a6d1ae4dc2 100644 --- a/arch/powerpc/platforms/cell/spufs/syscalls.c +++ b/arch/powerpc/platforms/cell/spufs/syscalls.c @@ -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_thread(&nd, flags, mode); + ret = spufs_create(&nd, flags, mode); path_release(&nd); } putname(tmp); diff --git a/include/asm-powerpc/spu.h b/include/asm-powerpc/spu.h index 87cc21e219..83b6dae48e 100644 --- a/include/asm-powerpc/spu.h +++ b/include/asm-powerpc/spu.h @@ -181,7 +181,10 @@ extern struct spufs_calls { * Flags for sys_spu_create. */ #define SPU_CREATE_EVENTS_ENABLED 0x0001 -#define SPU_CREATE_FLAG_ALL 0x0001 /* mask of all valid flags */ +#define SPU_CREATE_GANG 0x0002 + +#define SPU_CREATE_FLAG_ALL 0x0003 /* mask of all valid flags */ + #ifdef CONFIG_SPU_FS_MODULE int register_spu_syscalls(struct spufs_calls *calls);