mm/slub.c:2142:15: warning: variable 'partial_slabs' set but not used

[kernel test robot <philip.li@intel.com>]

Hi Vlastimil,

FYI, the error/warning was bisected to this commit, please ignore it if it's irrelevant.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   3f86ed6ec0b390c033eae7f9c487a3fea268e027
commit: bb192ed9aa7191a5d65548f82c42b6750d65f569 mm/slub: Convert most struct page to struct slab by spatch
date:   1 year, 8 months ago
:::::: branch date: 12 hours ago
:::::: commit date: 1 year, 8 months ago
config: i386-allnoconfig (https://download.01.org/0day-ci/archive/20230905/202309051941.72ZiILCM-lkp@intel.com/config)
compiler: clang version 16.0.4 (https://github.com/llvm/llvm-project.git ae42196bc493ffe877a7e3dff8be32035dea4d07)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20230905/202309051941.72ZiILCM-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/r/202309051941.72ZiILCM-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> mm/slub.c:2142:15: warning: variable 'partial_slabs' set but not used [-Wunused-but-set-variable]
           unsigned int partial_slabs = 0;
                        ^
   mm/slub.c:1681:21: warning: unused function 'kmalloc_large_node_hook' [-Wunused-function]
   static inline void *kmalloc_large_node_hook(void *ptr, size_t size, gfp_t flags)
                       ^
   2 warnings generated.


vim +/partial_slabs +2142 mm/slub.c

49e2258586b423 Christoph Lameter 2011-08-09  2132  
81819f0fc8285a Christoph Lameter 2007-05-06  2133  /*
672bba3a4b2e65 Christoph Lameter 2007-05-09  2134   * Try to allocate a partial slab from a specific node.
81819f0fc8285a Christoph Lameter 2007-05-06  2135   */
8ba00bb68a067c Joonsoo Kim       2012-09-17  2136  static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
bb192ed9aa7191 Vlastimil Babka   2021-11-03  2137  			      struct slab **ret_slab, gfp_t gfpflags)
81819f0fc8285a Christoph Lameter 2007-05-06  2138  {
bb192ed9aa7191 Vlastimil Babka   2021-11-03  2139  	struct slab *slab, *slab2;
49e2258586b423 Christoph Lameter 2011-08-09  2140  	void *object = NULL;
4b1f449dedd2ff Vlastimil Babka   2021-05-11  2141  	unsigned long flags;
bb192ed9aa7191 Vlastimil Babka   2021-11-03 @2142  	unsigned int partial_slabs = 0;
81819f0fc8285a Christoph Lameter 2007-05-06  2143  
81819f0fc8285a Christoph Lameter 2007-05-06  2144  	/*
81819f0fc8285a Christoph Lameter 2007-05-06  2145  	 * Racy check. If we mistakenly see no partial slabs then we
81819f0fc8285a Christoph Lameter 2007-05-06  2146  	 * just allocate an empty slab. If we mistakenly try to get a
70b6d25ec59cbc Chen Tao          2020-10-15  2147  	 * partial slab and there is none available then get_partial()
672bba3a4b2e65 Christoph Lameter 2007-05-09  2148  	 * will return NULL.
81819f0fc8285a Christoph Lameter 2007-05-06  2149  	 */
81819f0fc8285a Christoph Lameter 2007-05-06  2150  	if (!n || !n->nr_partial)
81819f0fc8285a Christoph Lameter 2007-05-06  2151  		return NULL;
81819f0fc8285a Christoph Lameter 2007-05-06  2152  
4b1f449dedd2ff Vlastimil Babka   2021-05-11  2153  	spin_lock_irqsave(&n->list_lock, flags);
bb192ed9aa7191 Vlastimil Babka   2021-11-03  2154  	list_for_each_entry_safe(slab, slab2, &n->partial, slab_list) {
8ba00bb68a067c Joonsoo Kim       2012-09-17  2155  		void *t;
49e2258586b423 Christoph Lameter 2011-08-09  2156  
bb192ed9aa7191 Vlastimil Babka   2021-11-03  2157  		if (!pfmemalloc_match(slab, gfpflags))
8ba00bb68a067c Joonsoo Kim       2012-09-17  2158  			continue;
8ba00bb68a067c Joonsoo Kim       2012-09-17  2159  
bb192ed9aa7191 Vlastimil Babka   2021-11-03  2160  		t = acquire_slab(s, n, slab, object == NULL);
49e2258586b423 Christoph Lameter 2011-08-09  2161  		if (!t)
9b1ea29bc0d7b9 Linus Torvalds    2021-03-10  2162  			break;
49e2258586b423 Christoph Lameter 2011-08-09  2163  
12d79634f8d7af Alex Shi          2011-09-07  2164  		if (!object) {
bb192ed9aa7191 Vlastimil Babka   2021-11-03  2165  			*ret_slab = slab;
49e2258586b423 Christoph Lameter 2011-08-09  2166  			stat(s, ALLOC_FROM_PARTIAL);
49e2258586b423 Christoph Lameter 2011-08-09  2167  			object = t;
49e2258586b423 Christoph Lameter 2011-08-09  2168  		} else {
bb192ed9aa7191 Vlastimil Babka   2021-11-03  2169  			put_cpu_partial(s, slab, 0);
8028dcea8abbbd Alex Shi          2012-02-03  2170  			stat(s, CPU_PARTIAL_NODE);
bb192ed9aa7191 Vlastimil Babka   2021-11-03  2171  			partial_slabs++;
49e2258586b423 Christoph Lameter 2011-08-09  2172  		}
b47291ef02b0be Vlastimil Babka   2021-11-05  2173  #ifdef CONFIG_SLUB_CPU_PARTIAL
345c905d13a4ec Joonsoo Kim       2013-06-19  2174  		if (!kmem_cache_has_cpu_partial(s)
bb192ed9aa7191 Vlastimil Babka   2021-11-03  2175  			|| partial_slabs > s->cpu_partial_slabs / 2)
49e2258586b423 Christoph Lameter 2011-08-09  2176  			break;
b47291ef02b0be Vlastimil Babka   2021-11-05  2177  #else
b47291ef02b0be Vlastimil Babka   2021-11-05  2178  		break;
b47291ef02b0be Vlastimil Babka   2021-11-05  2179  #endif
49e2258586b423 Christoph Lameter 2011-08-09  2180  
497b66f2ecc978 Christoph Lameter 2011-08-09  2181  	}
4b1f449dedd2ff Vlastimil Babka   2021-05-11  2182  	spin_unlock_irqrestore(&n->list_lock, flags);
497b66f2ecc978 Christoph Lameter 2011-08-09  2183  	return object;
81819f0fc8285a Christoph Lameter 2007-05-06  2184  }
81819f0fc8285a Christoph Lameter 2007-05-06  2185  

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