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Subject[RFC v2 08/34] mm, slub: dissolve new_slab_objects() into ___slab_alloc()
Date
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.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
---
mm/slub.c | 50 ++++++++++++++++++--------------------------------
1 file changed, 18 insertions(+), 32 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index 38256e87dde8..87f652bf8e4d 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1825,6 +1825,8 @@ static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
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);
}
@@ -2550,36 +2552,6 @@ slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
#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)))
@@ -2726,13 +2698,27 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
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)))
--
2.31.1
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