Hi Nhat,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on akpm-mm/mm-everything]
[also build test ERROR on linus/master v6.1-rc2 next-20221027]
[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#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Nhat-Pham/Implement-writeback-for-zsmalloc/20221027-040711
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20221026200613.1031261-6-nphamcs%40gmail.com
patch subject: [PATCH 5/5] zsmalloc: Implement writeback mechanism for zsmalloc
config: csky-randconfig-r035-20221026
compiler: csky-linux-gcc (GCC) 12.1.0
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
        # https://github.com/intel-lab-lkp/linux/commit/2a23b8adb2a4ca453bb39a7991c93a803899c102
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Nhat-Pham/Implement-writeback-for-zsmalloc/20221027-040711
        git checkout 2a23b8adb2a4ca453bb39a7991c93a803899c102
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=csky SHELL=/bin/bash

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

All errors (new ones prefixed by >>):

   mm/zsmalloc.c: In function 'zs_reclaim_page':
>> mm/zsmalloc.c:2462:18: error: 'struct zs_pool' has no member named 'ops'
    2462 |         if (!pool->ops || !pool->ops->evict || list_empty(&pool->lru) ||
         |                  ^~
   mm/zsmalloc.c:2462:32: error: 'struct zs_pool' has no member named 'ops'
    2462 |         if (!pool->ops || !pool->ops->evict || list_empty(&pool->lru) ||
         |                                ^~
   mm/zsmalloc.c:2511:35: error: 'struct zs_pool' has no member named 'ops'
    2511 |                         ret = pool->ops->evict(pool, handle);
         |                                   ^~
   mm/zsmalloc.c: At top level:
   mm/zsmalloc.c:2452:12: warning: 'zs_reclaim_page' defined but not used [-Wunused-function]
    2452 | static int zs_reclaim_page(struct zs_pool *pool, unsigned int retries)
         |            ^~~~~~~~~~~~~~~


vim +2462 mm/zsmalloc.c

  2451	
  2452	static int zs_reclaim_page(struct zs_pool *pool, unsigned int retries)
  2453	{
  2454		int i, obj_idx, ret = 0;
  2455		unsigned long handle;
  2456		struct zspage *zspage;
  2457		struct page *page;
  2458		enum fullness_group fullness;
  2459	
  2460		/* Lock LRU and fullness list */
  2461		spin_lock(&pool->lock);
> 2462		if (!pool->ops || !pool->ops->evict || list_empty(&pool->lru) ||
  2463				retries == 0) {
  2464			spin_unlock(&pool->lock);
  2465			return -EINVAL;
  2466		}
  2467	
  2468		for (i = 0; i < retries; i++) {
  2469			struct size_class *class;
  2470	
  2471			zspage = list_last_entry(&pool->lru, struct zspage, lru);
  2472			list_del(&zspage->lru);
  2473	
  2474			/* zs_free may free objects, but not the zspage and handles */
  2475			zspage->under_reclaim = true;
  2476	
  2477			/* Lock backing pages into place */
  2478			lock_zspage(zspage);
  2479	
  2480			class = zspage_class(pool, zspage);
  2481			fullness = get_fullness_group(class, zspage);
  2482	
  2483			/* Lock out object allocations and object compaction */
  2484			remove_zspage(class, zspage, fullness);
  2485	
  2486			spin_unlock(&pool->lock);
  2487	
  2488			obj_idx = 0;
  2489			page = zspage->first_page;
  2490			while (1) {
  2491				handle = find_alloced_obj(class, page, &obj_idx);
  2492				if (!handle) {
  2493					page = get_next_page(page);
  2494					if (!page)
  2495						break;
  2496					obj_idx = 0;
  2497					continue;
  2498				}
  2499	
  2500				/*
  2501				 * This will write the object and call
  2502				 * zs_free.
  2503				 *
  2504				 * zs_free will free the object, but the
  2505				 * under_reclaim flag prevents it from freeing
  2506				 * the zspage altogether. This is necessary so
  2507				 * that we can continue working with the
  2508				 * zspage potentially after the last object
  2509				 * has been freed.
  2510				 */
  2511				ret = pool->ops->evict(pool, handle);
  2512				if (ret)
  2513					goto next;
  2514	
  2515				obj_idx++;
  2516			}
  2517	
  2518	next:
  2519			/* For freeing the zspage, or putting it back in the pool and LRU list. */
  2520			spin_lock(&pool->lock);
  2521			zspage->under_reclaim = false;
  2522	
  2523			if (!get_zspage_inuse(zspage)) {
  2524				/*
  2525				 * Fullness went stale as zs_free() won't touch it
  2526				 * while the page is removed from the pool. Fix it
  2527				 * up for the check in __free_zspage().
  2528				 */
  2529				zspage->fullness = ZS_EMPTY;
  2530	
  2531				__free_zspage(pool, class, zspage);
  2532				spin_unlock(&pool->lock);
  2533				return 0;
  2534			}
  2535	
  2536			putback_zspage(class, zspage);
  2537			list_add(&zspage->lru, &pool->lru);
  2538			unlock_zspage(zspage);
  2539		}
  2540	
  2541		spin_unlock(&pool->lock);
  2542		return -EAGAIN;
  2543	}
  2544	

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