From: Darrick J. Wong <djwong@kernel.org>
Date: Mon, 1 May 2023 23:16:12 +0000 (+1000)
Subject: xfs: check that per-cpu inodegc workers actually run on that cpu
X-Git-Tag: v6.4-rc2~21^2~2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=b37c4c8339cd394ea6b8b415026603320a185651;p=thirdparty%2Fkernel%2Flinux.git

xfs: check that per-cpu inodegc workers actually run on that cpu

Now that we've allegedly worked out the problem of the per-cpu inodegc
workers being scheduled on the wrong cpu, let's put in a debugging knob
to let us know if a worker ever gets mis-scheduled again.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
---

diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
index 58712113d5d6c..4b63c065ef19e 100644
--- a/fs/xfs/xfs_icache.c
+++ b/fs/xfs/xfs_icache.c
@@ -1856,6 +1856,8 @@ xfs_inodegc_worker(
 	struct xfs_inode	*ip, *n;
 	unsigned int		nofs_flag;
 
+	ASSERT(gc->cpu == smp_processor_id());
+
 	WRITE_ONCE(gc->items, 0);
 
 	if (!node)
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index f3269c0626f05..aaaf5ec13492d 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -66,6 +66,9 @@ struct xfs_inodegc {
 	/* approximate count of inodes in the list */
 	unsigned int		items;
 	unsigned int		shrinker_hits;
+#if defined(DEBUG) || defined(XFS_WARN)
+	unsigned int		cpu;
+#endif
 };
 
 /*
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 4d2e87462ac4a..7e706255f1650 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1095,6 +1095,9 @@ xfs_inodegc_init_percpu(
 
 	for_each_possible_cpu(cpu) {
 		gc = per_cpu_ptr(mp->m_inodegc, cpu);
+#if defined(DEBUG) || defined(XFS_WARN)
+		gc->cpu = cpu;
+#endif
 		init_llist_head(&gc->list);
 		gc->items = 0;
 		INIT_DELAYED_WORK(&gc->work, xfs_inodegc_worker);