linux-kernel - [RFC PATCH v4 1/9] slub: Reflow ___slab

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Message-Id: <20231031140741.79387-2-chengming.zhou@linux.dev>
Date:   Tue, 31 Oct 2023 14:07:33 +0000
From:   chengming.zhou@...ux.dev
To:     vbabka@...e.cz, cl@...ux.com, penberg@...nel.org,
        willy@...radead.org
Cc:     rientjes@...gle.com, iamjoonsoo.kim@....com,
        akpm@...ux-foundation.org, roman.gushchin@...ux.dev,
        42.hyeyoo@...il.com, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, chengming.zhou@...ux.dev,
        Chengming Zhou <zhouchengming@...edance.com>
Subject: [RFC PATCH v4 1/9] slub: Reflow ___slab_alloc()

From: Chengming Zhou <zhouchengming@...edance.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@...edance.com>
Reviewed-by: Vlastimil Babka <vbabka@...e.cz>
---
 mm/slub.c | 31 +++++++++++++++----------------
 1 file changed, 15 insertions(+), 16 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index 63d281dfacdb..0b0fdc8c189f 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3216,8 +3216,21 @@ 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);
@@ -3253,20 +3266,6 @@ 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
-- 
2.20.1