linux-kernel - [PATCH 2/3] mm/slab: delete cache_alloc_debugcheck

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Date:   Sun,  5 Jun 2022 17:25:38 +0200
From:   Daniel Vetter <daniel.vetter@...ll.ch>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     DRI Development <dri-devel@...ts.freedesktop.org>,
        Daniel Vetter <daniel.vetter@...ll.ch>,
        Daniel Vetter <daniel.vetter@...el.com>,
        Christoph Lameter <cl@...ux.com>,
        Pekka Enberg <penberg@...nel.org>,
        David Rientjes <rientjes@...gle.com>,
        Joonsoo Kim <iamjoonsoo.kim@....com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Vlastimil Babka <vbabka@...e.cz>,
        Roman Gushchin <roman.gushchin@...ux.dev>, linux-mm@...ck.org
Subject: [PATCH 2/3] mm/slab: delete cache_alloc_debugcheck_before()

It only does a might_sleep_if(GFP_RECLAIM) check, which is already
covered by the might_alloc() in slab_pre_alloc_hook(). And all callers
of cache_alloc_debugcheck_before() call that beforehand already.

Signed-off-by: Daniel Vetter <daniel.vetter@...el.com>
Cc: Christoph Lameter <cl@...ux.com>
Cc: Pekka Enberg <penberg@...nel.org>
Cc: David Rientjes <rientjes@...gle.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@....com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Vlastimil Babka <vbabka@...e.cz>
Cc: Roman Gushchin <roman.gushchin@...ux.dev>
Cc: linux-mm@...ck.org
---
 mm/slab.c | 10 ----------
 1 file changed, 10 deletions(-)

diff --git a/mm/slab.c b/mm/slab.c
index b04e40078bdf..75779ac5f5ba 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2973,12 +2973,6 @@ static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags)
 	return ac->entry[--ac->avail];
 }
 
-static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep,
-						gfp_t flags)
-{
-	might_sleep_if(gfpflags_allow_blocking(flags));
-}
-
 #if DEBUG
 static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
 				gfp_t flags, void *objp, unsigned long caller)
@@ -3219,7 +3213,6 @@ slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid, size_t orig_
 	if (unlikely(ptr))
 		goto out_hooks;
 
-	cache_alloc_debugcheck_before(cachep, flags);
 	local_irq_save(save_flags);
 
 	if (nodeid == NUMA_NO_NODE)
@@ -3304,7 +3297,6 @@ slab_alloc(struct kmem_cache *cachep, struct list_lru *lru, gfp_t flags,
 	if (unlikely(objp))
 		goto out;
 
-	cache_alloc_debugcheck_before(cachep, flags);
 	local_irq_save(save_flags);
 	objp = __do_cache_alloc(cachep, flags);
 	local_irq_restore(save_flags);
@@ -3541,8 +3533,6 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
 	if (!s)
 		return 0;
 
-	cache_alloc_debugcheck_before(s, flags);
-
 	local_irq_disable();
 	for (i = 0; i < size; i++) {
 		void *objp = kfence_alloc(s, s->object_size, flags) ?: __do_cache_alloc(s, flags);
-- 
2.36.0