Merge tag 'slab-for-6.13-rc3' of git://git.kernel.org/pub/scm/linux/k…

…ernel/git/vbabka/slab

Pull slab fix from Vlastimil Babka:

 - Fix for memcg unreclaimable slab stats drift when post-charging large
   kmalloc allocations (Shakeel Butt)

* tag 'slab-for-6.13-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab:
  memcg: slub: fix SUnreclaim for post charged objects

mm/slub.c

@@ -2189,9 +2189,24 @@ bool memcg_slab_post_charge(void *p, gfp_t flags)
 
 	folio = virt_to_folio(p);
 	if (!folio_test_slab(folio)) {
-		return folio_memcg_kmem(folio) ||
-			(__memcg_kmem_charge_page(folio_page(folio, 0), flags,
-						  folio_order(folio)) == 0);
+		int size;
+
+		if (folio_memcg_kmem(folio))
+			return true;
+
+		if (__memcg_kmem_charge_page(folio_page(folio, 0), flags,
+					     folio_order(folio)))
+			return false;
+
+		/*
+		 * This folio has already been accounted in the global stats but
+		 * not in the memcg stats. So, subtract from the global and use
+		 * the interface which adds to both global and memcg stats.
+		 */
+		size = folio_size(folio);
+		node_stat_mod_folio(folio, NR_SLAB_UNRECLAIMABLE_B, -size);
+		lruvec_stat_mod_folio(folio, NR_SLAB_UNRECLAIMABLE_B, size);
+		return true;
 	}
 
 	slab = folio_slab(folio);