2020-11-20 09:59:12

by Daniel Vetter

Subject: [PATCH 3/3] locking/selftests: Add testcases for fs_reclaim

Since I butchered this I figured better to make sure we have testcases
for this now. Since we only have a locking context for __GFP_FS that's
the only thing we're testing right now.

Cc: [email protected]
Cc: Dave Chinner <[email protected]>
Cc: Qian Cai <[email protected]>
Cc: [email protected]
Cc: Thomas Hellström (Intel) <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: Maarten Lankhorst <[email protected]>
Cc: Christian König <[email protected]>
Cc: "Matthew Wilcox (Oracle)" <[email protected]>
Signed-off-by: Daniel Vetter <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: [email protected]
---
lib/locking-selftest.c | 47 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 47 insertions(+)

diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c
index a899b3f0e2e5..ad47c3358e30 100644
--- a/lib/locking-selftest.c
+++ b/lib/locking-selftest.c
@@ -15,6 +15,7 @@
#include <linux/mutex.h>
#include <linux/ww_mutex.h>
#include <linux/sched.h>
+#include <linux/sched/mm.h>
#include <linux/delay.h>
#include <linux/lockdep.h>
#include <linux/spinlock.h>
@@ -2357,6 +2358,50 @@ static void queued_read_lock_tests(void)
pr_cont("\n");
}

+static void fs_reclaim_correct_nesting(void)
+{
+ fs_reclaim_acquire(GFP_KERNEL);
+ might_alloc(GFP_NOFS);
+ fs_reclaim_release(GFP_KERNEL);
+}
+
+static void fs_reclaim_wrong_nesting(void)
+{
+ fs_reclaim_acquire(GFP_KERNEL);
+ might_alloc(GFP_KERNEL);
+ fs_reclaim_release(GFP_KERNEL);
+}
+
+static void fs_reclaim_protected_nesting(void)
+{
+ unsigned int flags;
+
+ fs_reclaim_acquire(GFP_KERNEL);
+ flags = memalloc_nofs_save();
+ might_alloc(GFP_KERNEL);
+ memalloc_nofs_restore(flags);
+ fs_reclaim_release(GFP_KERNEL);
+}
+
+static void fs_reclaim_tests(void)
+{
+ printk(" --------------------\n");
+ printk(" | fs_reclaim tests |\n");
+ printk(" --------------------\n");
+
+ print_testname("correct nesting");
+ dotest(fs_reclaim_correct_nesting, SUCCESS, 0);
+ pr_cont("\n");
+
+ print_testname("wrong nesting");
+ dotest(fs_reclaim_wrong_nesting, FAILURE, 0);
+ pr_cont("\n");
+
+ print_testname("protected nesting");
+ dotest(fs_reclaim_protected_nesting, SUCCESS, 0);
+ pr_cont("\n");
+}
+
void locking_selftest(void)
{
/*
@@ -2478,6 +2523,8 @@ void locking_selftest(void)
if (IS_ENABLED(CONFIG_QUEUED_RWLOCKS))
queued_read_lock_tests();

+ fs_reclaim_tests();
+
if (unexpected_testcase_failures) {
printk("-----------------------------------------------------------------\n");
debug_locks = 0;
--
2.29.2

2020-11-20 12:35:27

by Peter Zijlstra

Subject: Re: [PATCH 3/3] locking/selftests: Add testcases for fs_reclaim

On Fri, Nov 20, 2020 at 10:54:44AM +0100, Daniel Vetter wrote:
> Since I butchered this I figured better to make sure we have testcases
> for this now. Since we only have a locking context for __GFP_FS that's
> the only thing we're testing right now.
>
> Cc: [email protected]
> Cc: Dave Chinner <[email protected]>
> Cc: Qian Cai <[email protected]>
> Cc: [email protected]
> Cc: Thomas Hellstr?m (Intel) <[email protected]>
> Cc: Andrew Morton <[email protected]>
> Cc: Jason Gunthorpe <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: Maarten Lankhorst <[email protected]>
> Cc: Christian K?nig <[email protected]>
> Cc: "Matthew Wilcox (Oracle)" <[email protected]>
> Signed-off-by: Daniel Vetter <[email protected]>
> Cc: Peter Zijlstra <[email protected]>
> Cc: Ingo Molnar <[email protected]>
> Cc: Will Deacon <[email protected]>
> Cc: [email protected]
> ---
> lib/locking-selftest.c | 47 ++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 47 insertions(+)

I have a few changes pending for this file, I don't think the conflicts
will be bad, but..

In any case:

Acked-by: Peter Zijlstra (Intel) <[email protected]>