[PATCH] mm/slub: Simplify get_partial_node()

From: sxwjean@me.com
To: Christoph Lameter <cl@linux.com>,
	Pekka Enberg <penberg@kernel.org>,
	David Rientjes <rientjes@google.com>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Vlastimil Babka <vbabka@suse.cz>,
	Roman Gushchin <roman.gushchin@linux.dev>,
	Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Xiongwei Song <xiongwei.song@windriver.com>
Subject: [PATCH] mm/slub: Simplify get_partial_node()
Date: Mon, 11 Mar 2024 21:27:20 +0800	[thread overview]
Message-ID: <20240311132720.37741-1-sxwjean@me.com> (raw)

From: Xiongwei Song <xiongwei.song@windriver.com>

Remove the check of !kmem_cache_has_cpu_partial() because it is always
false, we've known this by calling kmem_cache_debug() before calling
remove_partial(), so we can remove the check.

Meanwhile, redo filling cpu partial and add comment to improve the
readability.

Signed-off-by: Xiongwei Song <xiongwei.song@windriver.com>
---
 mm/slub.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index a3ab096c38c0..62388f2a0ac7 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2620,19 +2620,21 @@ static struct slab *get_partial_node(struct kmem_cache *s,
 		if (!partial) {
 			partial = slab;
 			stat(s, ALLOC_FROM_PARTIAL);
-		} else {
+
+			/* Fill cpu partial if needed from next iteration, or break */
+			if (IS_ENABLED(CONFIG_SLUB_CPU_PARTIAL))
+				continue;
+			else
+				break;
+		}
+
+		if (IS_ENABLED(CONFIG_SLUB_CPU_PARTIAL)) {
 			put_cpu_partial(s, slab, 0);
 			stat(s, CPU_PARTIAL_NODE);
-			partial_slabs++;
-		}
-#ifdef CONFIG_SLUB_CPU_PARTIAL
-		if (!kmem_cache_has_cpu_partial(s)
-			|| partial_slabs > s->cpu_partial_slabs / 2)
-			break;
-#else
-		break;
-#endif
 
+			if (++partial_slabs > s->cpu_partial_slabs/2)
+				break;
+		}
 	}
 	spin_unlock_irqrestore(&n->list_lock, flags);
 	return partial;
-- 
2.34.1

