From: SeongJae Park <sjpark@xxxxxxxxx>
On Thu, 5 Aug 2021 17:43:04 -0700 Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> On Fri, 16 Jul 2021 08:14:43 +0000 SeongJae Park <sj38.park@xxxxxxxxx> wrote:
>
> > From: SeongJae Park <sjpark@xxxxxxxxx>
> >
> > DAMON is designed to be used by kernel space code such as the memory
> > management subsystems, and therefore it provides only kernel space API.
> > That said, letting the user space control DAMON could provide some
> > benefits to them. For example, it will allow user space to analyze
> > their specific workloads and make their own special optimizations.
> >
> > For such cases, this commit implements a simple DAMON application kernel
> > module, namely 'damon-dbgfs', which merely wraps the DAMON api and
> > exports those to the user space via the debugfs.
> >
> > ...
> >
> > +static int __init damon_dbgfs_init(void)
> > +{
> > + int rc;
> > +
> > + dbgfs_ctxs = kmalloc(sizeof(*dbgfs_ctxs), GFP_KERNEL);
> > + if (!dbgfs_ctxs) {
> > + pr_err("%s: dbgfs ctxs alloc failed\n", __func__);
> > + return -ENOMEM;
> > + }
> > + dbgfs_ctxs[0] = dbgfs_new_ctx();
> > + if (!dbgfs_ctxs[0]) {
> > + kfree(dbgfs_ctxs);
> > + pr_err("%s: dbgfs ctx alloc failed\n", __func__);
> > + return -ENOMEM;
> > + }
>
> checkpatch points out that the "alloc failed" messages are unneeded -
> kmalloc(GFP_KERNEL) will have already emitted a stack trace. Is this
> fixup OK?
Yes, of course. I also see you already kindly applied this in the -mm tree[1],
appreciate!
[1] https://www.ozlabs.org/~akpm/mmotm/broken-out/mm-damon-implement-a-debugfs-based-user-space-interface-fix.patch
Thanks,
SeongJae Park
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