On Fri, May 22, 2020 at 03:52:39PM +0800, Muchun Song wrote:
> On Fri, May 22, 2020 at 12:47 AM Matthew Wilcox wrote:
> > > @@ -160,14 +168,23 @@ static int proc_fd_link(struct dentry *dentry,
> > > struct path *path)
> > > unsigned int fd = proc_fd(d_inode(dentry));
> > >
On Fri, May 22, 2020 at 12:47 AM Matthew Wilcox wrote:
>
> On Thu, May 21, 2020 at 08:38:35PM +0800, Muchun Song wrote:
> > +++ b/fs/proc/fd.c
> > @@ -34,19 +34,27 @@ static int seq_show(struct seq_file *m, void *v)
> > if (files) {
> > unsigned int fd = proc_fd(m->private);
>
On Thu, May 21, 2020 at 08:38:35PM +0800, Muchun Song wrote:
> +++ b/fs/proc/fd.c
> @@ -34,19 +34,27 @@ static int seq_show(struct seq_file *m, void *v)
> if (files) {
> unsigned int fd = proc_fd(m->private);
>
> - spin_lock(&files->file_lock);
> + rcu_
On Fri, May 22, 2020 at 12:06:46AM +0800, Muchun Song wrote:
> On Thu, May 21, 2020 at 11:21 PM Matthew Wilcox wrote:
> >
> > On Thu, May 21, 2020 at 08:38:35PM +0800, Muchun Song wrote:
> > > There is another safe way to get the file structure without
> > > holding the files->file_lock. That is r
On Thu, May 21, 2020 at 11:21 PM Matthew Wilcox wrote:
>
> On Thu, May 21, 2020 at 08:38:35PM +0800, Muchun Song wrote:
> > There is another safe way to get the file structure without
> > holding the files->file_lock. That is rcu lock, and this way
> > has better performance. So use the rcu lock i
On Thu, May 21, 2020 at 08:38:35PM +0800, Muchun Song wrote:
> There is another safe way to get the file structure without
> holding the files->file_lock. That is rcu lock, and this way
> has better performance. So use the rcu lock instead of the
> files->file_lock.
What makes you think this is sa
There is another safe way to get the file structure without
holding the files->file_lock. That is rcu lock, and this way
has better performance. So use the rcu lock instead of the
files->file_lock.
Signed-off-by: Muchun Song
---
fs/proc/fd.c | 31 ---
kernel/b
