Re: [PATCH v2] mm/zsmalloc: add statistics support

From: Minchan Kim
Date: Fri Dec 19 2014 - 19:10:57 EST


On Fri, Dec 19, 2014 at 04:06:48PM -0800, Andrew Morton wrote:
> On Sat, 20 Dec 2014 08:58:52 +0900 Minchan Kim <minchan@xxxxxxxxxx> wrote:
>
> > On Fri, Dec 19, 2014 at 03:45:48PM -0800, Andrew Morton wrote:
> > > On Sat, 20 Dec 2014 08:39:37 +0900 Minchan Kim <minchan@xxxxxxxxxx> wrote:
> > >
> > > > Then, we should fix debugfs_create_dir can return errno to propagate the error
> > > > to end user who can know it was failed ENOMEM or EEXIST.
> > >
> > > Impractical. Every caller of every debugfs interface will need to be
> > > changed!
> >
> > If you don't like changing of all of current caller, maybe, we can define
> > debugfs_create_dir_error and use it.
> >
> > struct dentry *debugfs_create_dir_err(const char *name, struct dentry *parent, int *err)
> > and tweak debugfs_create_dir.
> > struct dentry *debugfs_create_dir(const char *name, struct dentry *parent, int *err)

typo.

I meant this

static struct dentry *__create_file(const char *name, umode_t mode,
struct dentry *parent, void *data,
const struct file_operations *fops,
int *err)

> > {
> > ..
> > ..
> > if (error) {
> > *err = error;
> > dentry = NULL;
> > }
> > }
> >
> > Why not?
>
> It involves rehashing a lengthy argument with Greg.

Okay. Then, Ganesh,
please add warn message about duplicaed name possibility althoug
it's unlikely as it is.

Thanks.

>
> > >
> > > It's really irritating and dumb. What we're supposed to do is to
> > > optionally report the failure, then ignore it. This patch appears to
> > > be OK in that respect.
> >
> > At least, we should notify to the user why it was failed so he can fix
> > the name if it was duplicated. So if you don't want debugfs, at least
> > I want to warn all of reasons it can fail(at least, duplicated name)
> > to the user.
>
> Sure. The debugfs interface design is mistaken.
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