Commit 6263203e authored by Arnd Bergmann's avatar Arnd Bergmann Committed by Paul Mackerras
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[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: default avatarArnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent 9add11da
......@@ -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-
......
......@@ -27,7 +27,7 @@
#include <asm/spu_csa.h>
#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);
}
......
/*
* SPU file system
*
* (C) Copyright IBM Deutschland Entwicklung GmbH 2005
*
* Author: Arnd Bergmann <arndb@de.ibm.com>
*
* 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 <linux/list.h>
#include <linux/slab.h>
#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);
}
......@@ -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);
......
......@@ -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);
......
......@@ -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);
......
......@@ -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);
......
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