[RFC-2 PATCH 8/8] shared subtree

From: Ram Pai
Date: Mon Jul 18 2005 - 02:16:47 EST

code Optimization for pnode.c


fs/pnode.c | 478 ++++++++++++++++++++++++++++---------------------------------
1 files changed, 224 insertions(+), 254 deletions(-)

Index: 2.6.12.work1/fs/pnode.c
===================================================================
--- 2.6.12.work1.orig/fs/pnode.c
+++ 2.6.12.work1/fs/pnode.c
@@ -26,6 +26,7 @@
#include <asm/unistd.h>
#include <stdarg.h>

+
enum pnode_vfs_type {
PNODE_MEMBER_VFS = 0x01,
PNODE_SLAVE_VFS = 0x02
@@ -34,7 +35,7 @@ enum pnode_vfs_type {
static kmem_cache_t * pnode_cachep;

/* spinlock for pnode related operations */
- __cacheline_aligned_in_smp DEFINE_SPINLOCK(vfspnode_lock);
+__cacheline_aligned_in_smp DEFINE_SPINLOCK(vfspnode_lock);


void __init pnode_init(unsigned long mempages)
@@ -58,7 +59,7 @@ struct vfspnode * pnode_alloc(void)
return pnode;
}

-void pnode_free(struct vfspnode *pnode)
+void inline pnode_free(struct vfspnode *pnode)
{
kmem_cache_free(pnode_cachep, pnode);
}
@@ -147,7 +148,6 @@ static int pnode_next(struct pcontext *c
return 1;
}

-
static void inline pnode_add_mnt(struct vfspnode *pnode,
struct vfsmount *mnt, int slave)
{
@@ -180,6 +180,111 @@ void pnode_add_slave_mnt(struct vfspnode
pnode_add_mnt(pnode, mnt, 1);
}

+/*
+ * traverse the pnode tree and at each pnode encountered, execute the
+ * pnode_fnc(). For each vfsmount encountered call the vfs_fnc().
+ *
+ * @pnode: pnode tree to be traversed
+ * @in_data: input data
+ * @out_data: output data
+ * @pnode_func: function to be called when a new pnode is encountered.
+ * @vfs_func: function to be called on each slave and member vfs belonging
+ * to the pnode.
+ */
+static int pnode_traverse(struct vfspnode *pnode,
+ void *in_data,
+ void **out_data,
+ int (*pnode_pre_func)(struct vfspnode *,
+ void *, void **, va_list),
+ int (*pnode_post_func)(struct vfspnode *,
+ void *, va_list),
+ int (*vfs_func)(struct vfsmount *,
+ enum pnode_vfs_type, void *, va_list),
+ ...)
+{
+ va_list args;
+ int ret = 0, level;
+ void *my_data, *data_from_master;
+ struct vfspnode *master_pnode;
+ struct vfsmount *slave_mnt, *member_mnt, *t_m;
+ struct pcontext context;
+ static void *p_array[PNODE_MAX_SLAVE_LEVEL];
+
+ context.start = pnode;
+ context.pnode = NULL;
+ /*
+ * determine whether to process vfs first or the
+ * slave pnode first
+ */
+ while (pnode_next(&context)) {
+ level = context.level;
+ pnode = context.pnode;
+ master_pnode = context.master_pnode;
+
+ if (master_pnode) {
+ data_from_master = p_array[level-1];
+ my_data = NULL;
+ } else {
+ data_from_master = NULL;
+ my_data = in_data;
+ }
+
+ if (pnode_pre_func) {
+ va_start(args, vfs_func);
+ if((ret = pnode_pre_func(pnode,
+ data_from_master, &my_data, args)))
+ goto error;
+ va_end(args);
+ }
+
+ // traverse member vfsmounts
+ spin_lock(&vfspnode_lock);
+ list_for_each_entry_safe(member_mnt,
+ t_m, &pnode->pnode_vfs, mnt_pnode_mntlist) {
+
+ spin_unlock(&vfspnode_lock);
+ va_start(args, vfs_func);
+ if ((ret = vfs_func(member_mnt,
+ PNODE_MEMBER_VFS, my_data, args)))
+ goto error;
+ va_end(args);
+ spin_lock(&vfspnode_lock);
+ }
+ list_for_each_entry_safe(slave_mnt, t_m,
+ &pnode->pnode_slavevfs, mnt_pnode_mntlist) {
+
+ spin_unlock(&vfspnode_lock);
+ va_start(args, vfs_func);
+ if ((ret = vfs_func(slave_mnt, PNODE_SLAVE_VFS,
+ my_data, args)))
+ goto error;
+ va_end(args);
+ spin_lock(&vfspnode_lock);
+ }
+ spin_unlock(&vfspnode_lock);
+
+ if (pnode_post_func) {
+ va_start(args, vfs_func);
+ if((ret = pnode_post_func(pnode,
+ my_data, args)))
+ goto error;
+ va_end(args);
+ }
+
+ p_array[level] = my_data;
+ }
+out:
+ if (out_data)
+ *out_data = p_array[0];
+ return ret;
+error:
+ va_end(args);
+ if (out_data)
+ *out_data = NULL;
+ goto out;
+}
+
+
void pnode_add_slave_pnode(struct vfspnode *pnode,
struct vfspnode *slave_pnode)
{
@@ -219,6 +324,7 @@ void pnode_del_member_mnt(struct vfsmoun
CLEAR_MNT_SHARED(mnt);
}

+
void pnode_disassociate_mnt(struct vfsmount *mnt)
{
if (!mnt)
@@ -228,6 +334,7 @@ void pnode_disassociate_mnt(struct vfsmo
CLEAR_MNT_SLAVE(mnt);
}

+
// merge pnode into peer_pnode and get rid of pnode
int pnode_merge_pnode(struct vfspnode *pnode, struct vfspnode *peer_pnode)
{
@@ -268,15 +375,18 @@ int pnode_merge_pnode(struct vfspnode *p
* with some cost.
*/
for (i=0 ; i <count; i++)
- put_pnode_unlocked(pnode);
+ put_pnode_locked(pnode);
spin_unlock(&vfspnode_lock);
return 0;
}

-static int vfs_busy(struct vfsmount *mnt, struct dentry *dentry,
- struct dentry *rootdentry, struct vfsmount *origmnt,
- int refcnt)
+static int vfs_busy(struct vfsmount *mnt, enum pnode_vfs_type flag,
+ void *indata, va_list args)
{
+ struct dentry *dentry = va_arg(args, struct dentry *);
+ struct dentry *rootdentry = va_arg(args, struct dentry *);
+ struct vfsmount *origmnt = va_arg(args, struct vfsmount *);
+ int refcnt = va_arg(args, int);
struct vfsmount *child_mnt;
int ret=0;

@@ -290,7 +400,7 @@ static int vfs_busy(struct vfsmount *mnt
if (list_empty(&child_mnt->mnt_mounts)) {
if (origmnt == child_mnt)
ret = do_refcount_check(child_mnt, refcnt+1);
- else
+ else
ret = do_refcount_check(child_mnt, refcnt);
}
mntput(child_mnt);
@@ -300,52 +410,32 @@ static int vfs_busy(struct vfsmount *mnt
int pnode_mount_busy(struct vfspnode *pnode, struct dentry *mntpt,
struct dentry *root, struct vfsmount *mnt, int refcnt)
{
- int ret=0;
- struct vfsmount *slave_mnt, *member_mnt, *t_m;
- struct pcontext context;
-
- context.start = pnode;
- context.pnode = NULL;
- while (pnode_next(&context)) {
- pnode = context.pnode;
-
- // traverse member vfsmounts
- spin_lock(&vfspnode_lock);
- list_for_each_entry_safe(member_mnt,
- t_m, &pnode->pnode_vfs, mnt_pnode_mntlist) {
- spin_unlock(&vfspnode_lock);
- if ((ret = vfs_busy(member_mnt, mntpt,
- root, mnt)))
- goto out;
- spin_lock(&vfspnode_lock);
- }
- list_for_each_entry_safe(slave_mnt, t_m,
- &pnode->pnode_slavevfs, mnt_pnode_mntlist) {
- spin_unlock(&vfspnode_lock);
- if ((ret = vfs_busy(slave_mnt, mntpt,
- root, mnt)))
- goto out;
- spin_lock(&vfspnode_lock);
- }
- spin_unlock(&vfspnode_lock);
- }
-out:
- return ret;
+ return pnode_traverse(pnode, NULL, NULL,
+ NULL, NULL, vfs_busy, mntpt, root, mnt, refcnt);
}

-int vfs_umount(struct vfsmount *mnt, struct dentry *dentry,
- struct dentry *rootdentry)
+
+int vfs_umount(struct vfsmount *mnt, enum pnode_vfs_type flag,
+ void *indata, va_list args)
{
struct vfsmount *child_mnt;
+ struct dentry *dentry, *rootdentry;
+
+
+ dentry = va_arg(args, struct dentry *);
+ rootdentry = va_arg(args, struct dentry *);

spin_unlock(&vfsmount_lock);
child_mnt = __lookup_mnt(mnt, dentry, rootdentry);
spin_lock(&vfsmount_lock);
mntput(child_mnt);
if (child_mnt && list_empty(&child_mnt->mnt_mounts)) {
- do_detach_mount(child_mnt);
- if (child_mnt->mnt_pnode)
+ if (IS_MNT_SHARED(child_mnt) ||
+ IS_MNT_SLAVE(child_mnt)) {
+ BUG_ON(!child_mnt->mnt_pnode);
pnode_disassociate_mnt(child_mnt);
+ }
+ do_detach_mount(child_mnt);
}
return 0;
}
@@ -353,34 +443,54 @@ int vfs_umount(struct vfsmount *mnt, str
int pnode_umount(struct vfspnode *pnode, struct dentry *dentry,
struct dentry *rootdentry)
{
+ return pnode_traverse(pnode, NULL, (void *)NULL,
+ NULL, NULL, vfs_umount, dentry, rootdentry);
+}
+
+
+int pnode_mount_func(struct vfspnode *pnode, void *indata,
+ void **outdata, va_list args)
+{
+ struct vfspnode *pnode_slave, *pnode_master;
int ret=0;
- struct vfsmount *slave_mnt, *member_mnt, *t_m;
- struct pcontext context;

- context.start = pnode;
- context.pnode = NULL;
- while (pnode_next(&context)) {
- pnode = context.pnode;
- // traverse member vfsmounts
- spin_lock(&vfspnode_lock);
- list_for_each_entry_safe(member_mnt,
- t_m, &pnode->pnode_vfs, mnt_pnode_mntlist) {
- spin_unlock(&vfspnode_lock);
- if ((ret = vfs_umount(member_mnt,
- dentry, rootdentry)))
- goto out;
- spin_lock(&vfspnode_lock);
- }
- list_for_each_entry_safe(slave_mnt, t_m,
- &pnode->pnode_slavevfs, mnt_pnode_mntlist) {
- spin_unlock(&vfspnode_lock);
- if ((ret = vfs_umount(slave_mnt,
- dentry, rootdentry)))
- goto out;
- spin_lock(&vfspnode_lock);
- }
- spin_unlock(&vfspnode_lock);
+ pnode_master = indata;
+
+ if (*outdata)
+ pnode_slave = *outdata;
+ else if (!(pnode_slave = pnode_alloc()))
+ return -ENOMEM;
+
+ *outdata = pnode_slave;
+
+ if (pnode_slave && pnode_master)
+ pnode_add_slave_pnode(pnode_master, pnode_slave);
+ return ret;
+}
+
+int vfs_make_mounted_func(struct vfsmount *mnt, enum pnode_vfs_type flag,
+ void *indata, va_list args)
+{
+ struct dentry *target_dentry;
+ int ret=0;
+ struct vfsmount *child_mount;
+ struct vfspnode *pnode;
+
+ target_dentry = va_arg(args, struct dentry *);
+ if (!(child_mount = do_make_mounted(mnt, target_dentry))) {
+ ret = -ENOMEM;
+ goto out;
}
+ pnode = (struct vfspnode *)indata;
+ switch (flag) {
+ case PNODE_SLAVE_VFS :
+ pnode_add_slave_mnt(pnode, child_mount);
+ break;
+ case PNODE_MEMBER_VFS :
+ pnode_add_member_mnt(pnode, child_mount);
+ break;
+ }
+
out:
return ret;
}
@@ -399,72 +509,17 @@ struct vfsmount *pnode_make_mounted(stru
struct vfsmount *mnt, struct dentry *dentry)
{
struct vfsmount *child_mnt;
- int ret=0, level;
- struct vfspnode *master_pnode;
- struct vfspnode *child_pnode, *master_child_pnode;
- struct vfsmount *slave_mnt, *member_mnt, *t_m;
- struct pcontext context;
- static struct vfspnode *p_array[PNODE_MAX_SLAVE_LEVEL];
-
- context.start = pnode;
- context.pnode = NULL;
-
- while (pnode_next(&context)) {
- level = context.level;
- pnode = context.pnode;
- master_pnode = context.master_pnode;
-
- if (master_pnode)
- master_child_pnode = p_array[level-1];
- else
- master_child_pnode = NULL;
-
- if (!(child_pnode = pnode_alloc())) {
- ret = -ENOMEM;
- goto out;
- }
-
- if (child_pnode && master_child_pnode)
- pnode_add_slave_pnode(master_child_pnode,
- child_pnode);
-
- p_array[level] = child_pnode;
-
- spin_lock(&vfspnode_lock);
- list_for_each_entry_safe(member_mnt,
- t_m, &pnode->pnode_vfs, mnt_pnode_mntlist) {
- spin_unlock(&vfspnode_lock);
- if (!(child_mnt = do_make_mounted(member_mnt,
- dentry))) {
- ret = -ENOMEM;
- goto out;
- }
- spin_lock(&vfspnode_lock);
- pnode_add_member_mnt(child_pnode, child_mnt);
- }
- list_for_each_entry_safe(slave_mnt, t_m,
- &pnode->pnode_slavevfs, mnt_pnode_mntlist) {
- spin_unlock(&vfspnode_lock);
- if (!(child_mnt = do_make_mounted(slave_mnt,
- dentry))) {
- ret = -ENOMEM;
- goto out;
- }
- spin_lock(&vfspnode_lock);
- pnode_add_slave_mnt(child_pnode, child_mnt);
- }
- spin_unlock(&vfspnode_lock);
- }
-out:
- if (ret)
- return NULL;
+ if(pnode_traverse(pnode, NULL, (void *)NULL,
+ pnode_mount_func, NULL, vfs_make_mounted_func,
+ (void *)dentry))
+ return NULL;

child_mnt = __lookup_mnt(mnt, dentry, dentry);
mntput(child_mnt);
return child_mnt;
}

-int vfs_make_unmounted(struct vfsmount *mnt)
+int vfs_make_unmounted_func(struct vfsmount *mnt)
{
struct vfspnode *pnode;
int ret=0;
@@ -473,58 +528,36 @@ int vfs_make_unmounted(struct vfsmount *
ret = 1;
goto out;
}
+
pnode = mnt->mnt_pnode;
+ spin_lock(&vfspnode_lock);
list_del_init(&mnt->mnt_pnode_mntlist);
- put_pnode(pnode);
+ put_pnode_locked(pnode);
+ spin_unlock(&vfspnode_lock);
out:
return ret;
}

int pnode_make_unmounted(struct vfspnode *pnode)
{
- int ret=0;
- struct vfsmount *slave_mnt, *member_mnt, *t_m;
- struct pcontext context;
-
- context.start = pnode;
- context.pnode = NULL;
- while (pnode_next(&context)) {
- pnode = context.pnode;
- // traverse member vfsmounts
- spin_lock(&vfspnode_lock);
- list_for_each_entry_safe(member_mnt,
- t_m, &pnode->pnode_vfs, mnt_pnode_mntlist) {
- spin_unlock(&vfspnode_lock);
- if ((ret = vfs_make_unmounted(member_mnt)))
- goto out;
- spin_lock(&vfspnode_lock);
- }
- list_for_each_entry_safe(slave_mnt, t_m,
- &pnode->pnode_slavevfs, mnt_pnode_mntlist) {
- spin_unlock(&vfspnode_lock);
- if ((ret = vfs_make_unmounted(slave_mnt)))
- goto out;
- spin_lock(&vfspnode_lock);
- }
- spin_unlock(&vfspnode_lock);
- }
-out:
- return ret;
+ return pnode_traverse(pnode, NULL, (void *)NULL,
+ NULL, NULL, vfs_make_unmounted_func);
}

int vfs_prepare_mount_func(struct vfsmount *mnt, enum pnode_vfs_type flag,
- struct vfspnode *pnode,
- struct vfsmount *source_mnt,
- struct dentry *mountpoint_dentry,
- struct vfsmount *p_mnt)
-
+ void *indata, va_list args)
{
- struct vfsmount *child_mnt;
+ struct vfsmount *source_mnt, *child_mnt, *p_mnt;
+ struct dentry *mountpoint_dentry;
+ struct vfspnode *pnode = (struct vfspnode *)indata;
+
+ source_mnt = va_arg(args, struct vfsmount * );
+ mountpoint_dentry = va_arg(args, struct dentry *);
+ p_mnt = va_arg(args, struct vfsmount *);

if ((p_mnt != mnt) || (source_mnt == source_mnt->mnt_parent)) {
child_mnt = do_attach_prepare_mnt(mnt, mountpoint_dentry,
source_mnt, (p_mnt != mnt));
-
if (!child_mnt)
return -ENOMEM;

@@ -546,71 +579,43 @@ int vfs_prepare_mount_func(struct vfsmou
}

int pnode_prepare_mount(struct vfspnode *pnode,
- struct vfspnode *my_pnode,
+ struct vfspnode *master_child_pnode,
struct dentry *mountpoint_dentry,
struct vfsmount *source_mnt,
struct vfsmount *mnt)
{
- int ret=0, level;
- struct vfspnode *master_pnode, *child_pnode, *master_child_pnode;
- struct vfsmount *slave_mnt, *member_mnt, *t_m;
- struct pcontext context;
- static struct vfspnode *p_array[PNODE_MAX_SLAVE_LEVEL];
-
- context.start = pnode;
- context.pnode = NULL;
- while (pnode_next(&context)) {
- level = context.level;
- pnode = context.pnode;
- master_pnode = context.master_pnode;
-
- if (master_pnode) {
- master_child_pnode = p_array[level];
- child_pnode = NULL;
- } else {
- master_child_pnode = NULL;
- child_pnode = my_pnode;
- }
-
- if (!(child_pnode = pnode_alloc()))
- return -ENOMEM;
-
- if (master_child_pnode && child_pnode)
- pnode_add_slave_pnode(master_child_pnode,
- child_pnode);
- p_array[level] = child_pnode;
+ return pnode_traverse(pnode,
+ master_child_pnode,
+ (void *)NULL,
+ pnode_mount_func,
+ NULL,
+ vfs_prepare_mount_func,
+ source_mnt,
+ mountpoint_dentry,
+ mnt);
+}

+int pnode_real_mount_post_func(struct vfspnode *pnode, void *indata,
+ va_list args)
+{
+ if (va_arg(args, int)) {
spin_lock(&vfspnode_lock);
- list_for_each_entry_safe(member_mnt,
- t_m, &pnode->pnode_vfs, mnt_pnode_mntlist) {
- spin_unlock(&vfspnode_lock);
- if((ret=vfs_prepare_mount_func(member_mnt,
- PNODE_MEMBER_VFS, child_pnode,
- source_mnt, mountpoint_dentry, mnt)))
- goto out;
- spin_lock(&vfspnode_lock);
- }
- list_for_each_entry_safe(slave_mnt,
- t_m, &pnode->pnode_slavevfs,
- mnt_pnode_mntlist) {
- spin_unlock(&vfspnode_lock);
- if((ret = vfs_prepare_mount_func(slave_mnt,
- PNODE_SLAVE_VFS, child_pnode,
- source_mnt, mountpoint_dentry, mnt)))
- goto out;
- spin_lock(&vfspnode_lock);
- }
+ BUG_ON(!list_empty(&pnode->pnode_vfs));
+ BUG_ON(!list_empty(&pnode->pnode_slavevfs));
+ BUG_ON(!list_empty(&pnode->pnode_slavepnode));
+ list_del_init(&pnode->pnode_peer_slave);
+ put_pnode_locked(pnode);
spin_unlock(&vfspnode_lock);
}
-out:
- return ret;
+ return 0;
}

-int vfs_real_mount_func(struct vfsmount *mnt, int delflag)
+int vfs_real_mount_func(struct vfsmount *mnt, enum pnode_vfs_type flag,
+ void *indata, va_list args)
{
BUG_ON(mnt == mnt->mnt_parent);
do_attach_real_mnt(mnt);
- if (delflag) {
+ if (va_arg(args, int)) {
spin_lock(&vfspnode_lock);
list_del_init(&mnt->mnt_pnode_mntlist);
put_pnode_locked(mnt->mnt_pnode);
@@ -628,42 +633,7 @@ int vfs_real_mount_func(struct vfsmount
*/
int pnode_real_mount(struct vfspnode *pnode, int flag)
{
- int ret=0;
- struct vfsmount *slave_mnt, *member_mnt, *t_m;
- struct pcontext context;
-
- context.start = pnode;
- context.pnode = NULL;
- while (pnode_next(&context)) {
- pnode = context.pnode;
- // traverse member vfsmounts
- spin_lock(&vfspnode_lock);
- list_for_each_entry_safe(member_mnt,
- t_m, &pnode->pnode_vfs, mnt_pnode_mntlist) {
- spin_unlock(&vfspnode_lock);
- if ((ret = vfs_real_mount_func(member_mnt,
- flag)))
- goto out;
- spin_lock(&vfspnode_lock);
- }
- list_for_each_entry_safe(slave_mnt, t_m,
- &pnode->pnode_slavevfs, mnt_pnode_mntlist) {
- spin_unlock(&vfspnode_lock);
- if ((ret = vfs_real_mount_func(slave_mnt,
- flag)))
- goto out;
- spin_lock(&vfspnode_lock);
- }
-
- if (flag) {
- BUG_ON(!list_empty(&pnode->pnode_vfs));
- BUG_ON(!list_empty(&pnode->pnode_slavevfs));
- BUG_ON(!list_empty(&pnode->pnode_slavepnode));
- list_del_init(&pnode->pnode_peer_slave);
- put_pnode_locked(pnode);
- }
- spin_unlock(&vfspnode_lock);
- }
-out:
- return ret;
+ return pnode_traverse(pnode,
+ NULL, (void *)NULL, NULL, pnode_real_mount_post_func,
+ vfs_real_mount_func, flag);
}
-
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