p71924506
/
linux_old1
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

NFS: Convert lookups of the lock context to RCU 

Speed up lookups of an existing lock context by avoiding the inode->i_lock,
and using RCU instead.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
This commit is contained in:
Trond Myklebust 2018-09-02 15:11:57 -04:00
parent 28ced9a84c
commit 1db97eaa0b
2 changed files with 13 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
fs/nfs/inode.c
View File

@ -857,15 +857,14 @@ static void nfs_init_lock_context(struct nfs_lock_context *l_ctx)
static struct nfs_lock_context *__nfs_find_lock_context(struct nfs_open_context *ctx)
{
struct nfs_lock_context *head = &ctx->lock_context;
struct nfs_lock_context *pos = head;
struct nfs_lock_context *pos;
do {
list_for_each_entry_rcu(pos, &ctx->lock_context.list, list) {
if (pos->lockowner != current->files)
continue;
refcount_inc(&pos->count);
return pos;
} while ((pos = list_entry(pos->list.next, typeof(*pos), list)) != head);
if (refcount_inc_not_zero(&pos->count))
return pos;
}
return NULL;
}
@ -874,10 +873,10 @@ struct nfs_lock_context *nfs_get_lock_context(struct nfs_open_context *ctx)
struct nfs_lock_context *res, *new = NULL;
struct inode *inode = d_inode(ctx->dentry);
spin_lock(&inode->i_lock);
rcu_read_lock();
res = __nfs_find_lock_context(ctx);
rcu_read_unlock();
if (res == NULL) {
spin_unlock(&inode->i_lock);
new = kmalloc(sizeof(*new), GFP_KERNEL);
if (new == NULL)
return ERR_PTR(-ENOMEM);
@ -885,14 +884,14 @@ struct nfs_lock_context *nfs_get_lock_context(struct nfs_open_context *ctx)
spin_lock(&inode->i_lock);
res = __nfs_find_lock_context(ctx);
if (res == NULL) {
list_add_tail(&new->list, &ctx->lock_context.list);
list_add_tail_rcu(&new->list, &ctx->lock_context.list);
new->open_context = ctx;
res = new;
new = NULL;
}
spin_unlock(&inode->i_lock);
kfree(new);
}
spin_unlock(&inode->i_lock);
kfree(new);
return res;
}
EXPORT_SYMBOL_GPL(nfs_get_lock_context);
@ -904,9 +903,9 @@ void nfs_put_lock_context(struct nfs_lock_context *l_ctx)
if (!refcount_dec_and_lock(&l_ctx->count, &inode->i_lock))
return;
list_del(&l_ctx->list);
list_del_rcu(&l_ctx->list);
spin_unlock(&inode->i_lock);
kfree(l_ctx);
kfree_rcu(l_ctx, rcu_head);
}
EXPORT_SYMBOL_GPL(nfs_put_lock_context);

1
include/linux/nfs_fs.h
View File

@ -62,6 +62,7 @@ struct nfs_lock_context {
struct nfs_open_context *open_context;
fl_owner_t lockowner;
atomic_t io_count;
struct rcu_head rcu_head;
};
struct nfs4_state;