Re: [PATCH v4 35/35] mm, slub: convert kmem_cpu_slab protection to local_lock
From: Vlastimil Babka <hidden>
Date: 2021-08-17 09:32:46
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On 8/17/21 11:12 AM, Sebastian Andrzej Siewior wrote:
On 2021-08-17 10:37:48 [+0200], Vlastimil Babka wrote:quoted
OK reproduced. Thanks, will investigate.With the local_lock at the top, the needed alignment gets broken for dbl cmpxchg.
Right. I wondered why the checks in __pcpu_double_call_return_bool didn't trigger. They are VM_BUG_ON() so they did trigger after enabling DEBUG_VM.
quoted hunk ↗ jump to hunk
diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h index b5bcac29b979c..cd14aa1f9bc3c 100644 --- a/include/linux/slub_def.h +++ b/include/linux/slub_def.h@@ -42,9 +42,9 @@ enum stat_item { NR_SLUB_STAT_ITEMS }; struct kmem_cache_cpu { - local_lock_t lock; /* Protects the fields below except stat */ void **freelist; /* Pointer to next available object */ unsigned long tid; /* Globally unique transaction id */ + local_lock_t lock; /* Protects the fields below except stat */ struct page *page; /* The slab from which we are allocating */ #ifdef CONFIG_SLUB_CPU_PARTIAL struct page *partial; /* Partially allocated frozen slabs */Sebastian