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From:   chengming.zhou@linux.dev
To:     cl@linux.com, penberg@kernel.org
Cc:     rientjes@google.com, iamjoonsoo.kim@lge.com,
        akpm@linux-foundation.org, vbabka@suse.cz,
        roman.gushchin@linux.dev, 42.hyeyoo@gmail.com, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, chengming.zhou@linux.dev,
        Chengming Zhou <zhouchengming@bytedance.com>
Subject: [RFC PATCH v3 3/7] slub: Reflow ___slab_alloc()
Date:   Tue, 24 Oct 2023 09:33:41 +0000
Message-Id: <20231024093345.3676493-4-chengming.zhou@linux.dev>
In-Reply-To: <20231024093345.3676493-1-chengming.zhou@linux.dev>
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From: Chengming Zhou <zhouchengming@bytedance.com>

The get_partial() interface used in ___slab_alloc() may return a single
object in the "kmem_cache_debug(s)" case, in which we will just return
the "freelist" object.

Move this handling up to prepare for later changes.

And the "pfmemalloc_match()" part is not needed for node partial slab,
since we already check this in the get_partial_node().

Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
---
 mm/slub.c | 31 +++++++++++++++----------------
 1 file changed, 15 insertions(+), 16 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index f568a32d7332..cd8aa68c156e 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3218,8 +3218,21 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 	pc.slab = &slab;
 	pc.orig_size = orig_size;
 	freelist = get_partial(s, node, &pc);
-	if (freelist)
-		goto check_new_slab;
+	if (freelist) {
+		if (kmem_cache_debug(s)) {
+			/*
+			 * For debug caches here we had to go through
+			 * alloc_single_from_partial() so just store the
+			 * tracking info and return the object.
+			 */
+			if (s->flags & SLAB_STORE_USER)
+				set_track(s, freelist, TRACK_ALLOC, addr);
+
+			return freelist;
+		}
+
+		goto retry_load_slab;
+	}
 
 	slub_put_cpu_ptr(s->cpu_slab);
 	slab = new_slab(s, gfpflags, node);
@@ -3255,20 +3268,6 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
 
 	inc_slabs_node(s, slab_nid(slab), slab->objects);
 
-check_new_slab:
-
-	if (kmem_cache_debug(s)) {
-		/*
-		 * For debug caches here we had to go through
-		 * alloc_single_from_partial() so just store the tracking info
-		 * and return the object
-		 */
-		if (s->flags & SLAB_STORE_USER)
-			set_track(s, freelist, TRACK_ALLOC, addr);
-
-		return freelist;
-	}
-
 	if (unlikely(!pfmemalloc_match(slab, gfpflags))) {
 		/*
 		 * For !pfmemalloc_match() case we don't load freelist so that
-- 
2.40.1