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?
--- a/mm/damon/dbgfs.c~mm-damon-implement-a-debugfs-based-user-space-interface-fix
+++ a/mm/damon/dbgfs.c
@@ -373,14 +373,11 @@ 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__);
+ if (!dbgfs_ctxs)
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;
}
dbgfs_nr_ctxs = 1;
_
