Hi Neil,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on v5.12-rc5]
[also build test ERROR on next-20210401]
[cannot apply to hnaz-linux-mm/master]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Neil-Sun/mm-vmscan-c-drop_slab_node-with-task-s-memcg/20210402-184123
base:    a5e13c6df0e41702d2b2c77c8ad41677ebb065b3
config: mips-randconfig-r006-20210402 (attached as .config)
compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project b23a314146956dd29b719ab537608ced736fc036)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install mips cross compiling tool for clang build
        # apt-get install binutils-mips-linux-gnu
        # https://github.com/0day-ci/linux/commit/73abc13485ec57de137f60535b5b2495c0bac570
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Neil-Sun/mm-vmscan-c-drop_slab_node-with-task-s-memcg/20210402-184123
        git checkout 73abc13485ec57de137f60535b5b2495c0bac570
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=mips 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All error/warnings (new ones prefixed by >>):

>> mm/vmscan.c:705:11: error: implicit declaration of function 'mem_cgroup_from_task' [-Werror,-Wimplicit-function-declaration]
                   memcg = mem_cgroup_from_task(current);
                           ^
>> mm/vmscan.c:705:9: warning: incompatible integer to pointer conversion assigning to 'struct mem_cgroup *' from 'int' [-Wint-conversion]
                   memcg = mem_cgroup_from_task(current);
                         ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   1 warning and 1 error generated.


vim +/mem_cgroup_from_task +705 mm/vmscan.c

   693	
   694	void drop_slab_node(int nid)
   695	{
   696		unsigned long freed;
   697	
   698		do {
   699			struct mem_cgroup *memcg = NULL;
   700	
   701			if (fatal_signal_pending(current))
   702				return;
   703	
   704			freed = 0;
 > 705			memcg = mem_cgroup_from_task(current);
   706			do {
   707				freed += shrink_slab(GFP_KERNEL, nid, memcg, 0);
   708			} while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)) != NULL);
   709		} while (freed > 10);
   710	}
   711	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org