Re: [PATCH] mm: unhide vmstat_text definition for CONFIG_SMP

[Andrew Morton <akpm@linux-foundation.org>]

On Mon, 16 May 2016 16:23:33 +0200 Michal Hocko <mhocko@kernel.org> wrote:

> Andrew, I think that the following is more straightforward fix and
> should be folded in to the patch which has introduced vmstat_refresh.
> ---
> >From b8dd18fb7df040e1bfe61aadde1d903589de15e4 Mon Sep 17 00:00:00 2001
> From: Michal Hocko <mhocko@suse.com>
> Date: Mon, 16 May 2016 16:19:53 +0200
> Subject: [PATCH] mmotm: mm-proc-sys-vm-stat_refresh-to-force-vmstat-update-fix
> 
> Arnd has reported:
> In randconfig builds with sysfs, procfs and numa all disabled,
> but SMP enabled, we now get a link error in the newly introduced
> vmstat_refresh function:
> 
> mm/built-in.o: In function `vmstat_refresh':
> :(.text+0x15c78): undefined reference to `vmstat_text'
> 
> vmstat_refresh is proc_fs specific so there is no reason to define it
> when !CONFIG_PROC_FS.

I already had this:

From: Christoph Lameter <cl@linux.com>
Subject: Do not build vmstat_refresh if there is no procfs support

It makes no sense to build functionality into the kernel that
cannot be used and causes build issues.

Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1605111011260.9351@east.gentwo.org
Signed-off-by: Christoph Lameter <cl@linux.com>
Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/vmstat.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff -puN mm/vmstat.c~mm-proc-sys-vm-stat_refresh-to-force-vmstat-update-fix mm/vmstat.c
--- a/mm/vmstat.c~mm-proc-sys-vm-stat_refresh-to-force-vmstat-update-fix
+++ a/mm/vmstat.c
@@ -1371,7 +1371,6 @@ static const struct file_operations proc
 	.llseek		= seq_lseek,
 	.release	= seq_release,
 };
-#endif /* CONFIG_PROC_FS */
 
 #ifdef CONFIG_SMP
 static struct workqueue_struct *vmstat_wq;
@@ -1436,7 +1435,10 @@ int vmstat_refresh(struct ctl_table *tab
 		*lenp = 0;
 	return 0;
 }
+#endif /* CONFIG_SMP */
+#endif /* CONFIG_PROC_FS */
 
+#ifdef CONFIG_SMP
 static void vmstat_update(struct work_struct *w)
 {
 	if (refresh_cpu_vm_stats(true)) {
_