[016/212] mm, slub: dissolve new_slab_objects() into ___slab_alloc()

Commit Message

Andrew Morton Sept. 2, 2021, 9:50 p.m. UTC

From: Vlastimil Babka <[e-mail]>
Subject: mm, slub: dissolve new_slab_objects() into ___slab_alloc()

The later patches will need more fine grained control over individual
actions in ___slab_alloc(), the only caller of new_slab_objects(), so
dissolve it there.  This is a preparatory step with no functional change.

The only minor change is moving WARN_ON_ONCE() for using a constructor
together with __GFP_ZERO to new_slab(), which makes it somewhat less
frequent, but still able to catch a development change introducing a
systematic misuse.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Vlastimil Babka <[e-mail]>
Acked-by: Christoph Lameter <[e-mail]>
Acked-by: Mel Gorman <[e-mail]>
Cc: David Rientjes <[e-mail]>
Cc: Jann Horn <[e-mail]>
Cc: Jesper Dangaard Brouer <[e-mail]>
Cc: Joonsoo Kim <[e-mail]>
Cc: Mike Galbraith <[e-mail]>
Cc: Pekka Enberg <[e-mail]>
Cc: Sebastian Andrzej Siewior <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 mm/slub.c |   50 ++++++++++++++++++--------------------------------
 1 file changed, 18 insertions(+), 32 deletions(-)

Patch

--- a/mm/slub.c~mm-slub-dissolve-new_slab_objects-into-___slab_alloc
+++ a/mm/slub.c
@@ -1871,6 +1871,8 @@  static struct page *new_slab(struct kmem
 	if (unlikely(flags & GFP_SLAB_BUG_MASK))
 		flags = kmalloc_fix_flags(flags);
 
+	WARN_ON_ONCE(s->ctor && (flags & __GFP_ZERO));
+
 	return allocate_slab(s,
 		flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
 }
@@ -2596,36 +2598,6 @@  slab_out_of_memory(struct kmem_cache *s,
 #endif
 }
 
-static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags,
-			int node, struct kmem_cache_cpu **pc)
-{
-	void *freelist = NULL;
-	struct kmem_cache_cpu *c = *pc;
-	struct page *page;
-
-	WARN_ON_ONCE(s->ctor && (flags & __GFP_ZERO));
-
-	page = new_slab(s, flags, node);
-	if (page) {
-		c = raw_cpu_ptr(s->cpu_slab);
-		if (c->page)
-			flush_slab(s, c);
-
-		/*
-		 * No other reference to the page yet so we can
-		 * muck around with it freely without cmpxchg
-		 */
-		freelist = page->freelist;
-		page->freelist = NULL;
-
-		stat(s, ALLOC_SLAB);
-		c->page = page;
-		*pc = c;
-	}
-
-	return freelist;
-}
-
 static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags)
 {
 	if (unlikely(PageSlabPfmemalloc(page)))
@@ -2772,13 +2744,27 @@  new_slab:
 	if (freelist)
 		goto check_new_page;
 
-	freelist = new_slab_objects(s, gfpflags, node, &c);
+	page = new_slab(s, gfpflags, node);
 
-	if (unlikely(!freelist)) {
+	if (unlikely(!page)) {
 		slab_out_of_memory(s, gfpflags, node);
 		return NULL;
 	}
 
+	c = raw_cpu_ptr(s->cpu_slab);
+	if (c->page)
+		flush_slab(s, c);
+
+	/*
+	 * No other reference to the page yet so we can
+	 * muck around with it freely without cmpxchg
+	 */
+	freelist = page->freelist;
+	page->freelist = NULL;
+
+	stat(s, ALLOC_SLAB);
+	c->page = page;
+
 check_new_page:
 	page = c->page;
 	if (likely(!kmem_cache_debug(s) && pfmemalloc_match(page, gfpflags)))