From: Vlastimil Babka <vbabka@suse.cz>
Date: Mon, 23 Aug 2021 23:59:01 +0000 (+1000)
Subject: mm, slab: make flush_slab() possible to call with irqs enabled
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=71699265dd7f1fe3ab36d19bbae4cb47da4f2736;p=users%2Fjedix%2Flinux-maple.git

mm, slab: make flush_slab() possible to call with irqs enabled

Currently flush_slab() is always called with disabled IRQs if it's needed,
but the following patches will change that, so add a parameter to control
IRQ disabling within the function, which only protects the kmem_cache_cpu
manipulation and not the call to deactivate_slab() which doesn't need it.

Link: https://lkml.kernel.org/r/20210805152000.12817-29-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
---

diff --git a/mm/slub.c b/mm/slub.c
index ddcaddc5e8017..bb7e055437389 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2480,16 +2480,28 @@ static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
 #endif	/* CONFIG_SLUB_CPU_PARTIAL */
 }
 
-static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
+static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c,
+			      bool lock)
 {
-	void *freelist = c->freelist;
-	struct page *page = c->page;
+	unsigned long flags;
+	void *freelist;
+	struct page *page;
+
+	if (lock)
+		local_irq_save(flags);
+
+	freelist = c->freelist;
+	page = c->page;
 
 	c->page = NULL;
 	c->freelist = NULL;
 	c->tid = next_tid(c->tid);
 
-	deactivate_slab(s, page, freelist);
+	if (lock)
+		local_irq_restore(flags);
+
+	if (page)
+		deactivate_slab(s, page, freelist);
 
 	stat(s, CPUSLAB_FLUSH);
 }
@@ -2499,7 +2511,7 @@ static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
 	struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
 
 	if (c->page)
-		flush_slab(s, c);
+		flush_slab(s, c, false);
 
 	unfreeze_partials_cpu(s, c);
 }
@@ -2515,7 +2527,7 @@ static void flush_cpu_slab(void *d)
 	struct kmem_cache_cpu *c = this_cpu_ptr(s->cpu_slab);
 
 	if (c->page)
-		flush_slab(s, c);
+		flush_slab(s, c, false);
 
 	unfreeze_partials(s);
 }