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Message-ID: <400e2b89-1ad7-4626-9ee0-e45a9e5b5227@suswa.mountain>
Date: Tue, 24 Jun 2025 17:47:14 +0300
From: Dan Carpenter <dan.carpenter@...aro.org>
To: oe-kbuild@...ts.linux.dev, Zhongkun He <hezhongkun.hzk@...edance.com>,
akpm@...ux-foundation.org, tytso@....edu, jack@...e.com,
hannes@...xchg.org, mhocko@...nel.org
Cc: lkp@...el.com, oe-kbuild-all@...ts.linux.dev, muchun.song@...ux.dev,
linux-ext4@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-mm@...ck.org, cgroups@...r.kernel.org,
Zhongkun He <hezhongkun.hzk@...edance.com>,
Muchun Song <songmuchun@...edance.com>
Subject: Re: [PATCH 1/2] mm: memcg: introduce PF_MEMALLOC_ACCOUNTFORCE to
postpone reclaim to return-to-userland path
Hi Zhongkun,
kernel test robot noticed the following build warnings:
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Zhongkun-He/mm-memcg-introduce-PF_MEMALLOC_ACCOUNTFORCE-to-postpone-reclaim-to-return-to-userland-path/20250618-194101
base: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link: https://lore.kernel.org/r/71a4bbc284048ceb38eaac53dfa1031f92ac52b7.1750234270.git.hezhongkun.hzk%40bytedance.com
patch subject: [PATCH 1/2] mm: memcg: introduce PF_MEMALLOC_ACCOUNTFORCE to postpone reclaim to return-to-userland path
config: i386-randconfig-141-20250619 (https://download.01.org/0day-ci/archive/20250624/202506242032.uShv7ASV-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
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@...el.com>
| Reported-by: Dan Carpenter <dan.carpenter@...aro.org>
| Closes: https://lore.kernel.org/r/202506242032.uShv7ASV-lkp@intel.com/
smatch warnings:
mm/memcontrol.c:2341 mem_cgroup_handle_over_max() warn: use 'gfp_mask' here instead of GFP_KERNEL?
vim +/gfp_mask +2341 mm/memcontrol.c
b5db553cc19549 Zhongkun He 2025-06-18 2320 void mem_cgroup_handle_over_max(gfp_t gfp_mask)
^^^^^^^^
b5db553cc19549 Zhongkun He 2025-06-18 2321 {
b5db553cc19549 Zhongkun He 2025-06-18 2322 unsigned long nr_reclaimed = 0;
b5db553cc19549 Zhongkun He 2025-06-18 2323 unsigned int nr_pages = current->memcg_nr_pages_over_max;
b5db553cc19549 Zhongkun He 2025-06-18 2324 int nr_retries = MAX_RECLAIM_RETRIES;
b5db553cc19549 Zhongkun He 2025-06-18 2325 struct mem_cgroup *memcg, *mem_over_limit;
b5db553cc19549 Zhongkun He 2025-06-18 2326
b5db553cc19549 Zhongkun He 2025-06-18 2327 if (likely(!nr_pages))
b5db553cc19549 Zhongkun He 2025-06-18 2328 return;
b5db553cc19549 Zhongkun He 2025-06-18 2329
b5db553cc19549 Zhongkun He 2025-06-18 2330 memcg = get_mem_cgroup_from_mm(current->mm);
b5db553cc19549 Zhongkun He 2025-06-18 2331 current->memcg_nr_pages_over_max = 0;
b5db553cc19549 Zhongkun He 2025-06-18 2332
b5db553cc19549 Zhongkun He 2025-06-18 2333 retry:
b5db553cc19549 Zhongkun He 2025-06-18 2334 mem_over_limit = get_over_limit_memcg(memcg);
b5db553cc19549 Zhongkun He 2025-06-18 2335 if (!mem_over_limit)
b5db553cc19549 Zhongkun He 2025-06-18 2336 goto out;
b5db553cc19549 Zhongkun He 2025-06-18 2337
b5db553cc19549 Zhongkun He 2025-06-18 2338 while (nr_reclaimed < nr_pages) {
b5db553cc19549 Zhongkun He 2025-06-18 2339 unsigned long reclaimed;
b5db553cc19549 Zhongkun He 2025-06-18 2340
b5db553cc19549 Zhongkun He 2025-06-18 @2341 reclaimed = try_to_free_mem_cgroup_pages(mem_over_limit,
b5db553cc19549 Zhongkun He 2025-06-18 2342 nr_pages, GFP_KERNEL,
I guess GFP_KERNEL is fine. The gfp_mask is used below. Don't worry
about this one if the GFP_KERNEL is intended. Just ignore the warning
message.
b5db553cc19549 Zhongkun He 2025-06-18 2343 MEMCG_RECLAIM_MAY_SWAP,
b5db553cc19549 Zhongkun He 2025-06-18 2344 NULL);
b5db553cc19549 Zhongkun He 2025-06-18 2345
b5db553cc19549 Zhongkun He 2025-06-18 2346 if (!reclaimed && !nr_retries--)
b5db553cc19549 Zhongkun He 2025-06-18 2347 break;
b5db553cc19549 Zhongkun He 2025-06-18 2348
b5db553cc19549 Zhongkun He 2025-06-18 2349 nr_reclaimed += reclaimed;
b5db553cc19549 Zhongkun He 2025-06-18 2350 }
b5db553cc19549 Zhongkun He 2025-06-18 2351
b5db553cc19549 Zhongkun He 2025-06-18 2352 if ((nr_reclaimed < nr_pages) &&
b5db553cc19549 Zhongkun He 2025-06-18 2353 (page_counter_read(&mem_over_limit->memory) >
b5db553cc19549 Zhongkun He 2025-06-18 2354 READ_ONCE(mem_over_limit->memory.max)) &&
b5db553cc19549 Zhongkun He 2025-06-18 2355 mem_cgroup_oom(mem_over_limit, gfp_mask,
b5db553cc19549 Zhongkun He 2025-06-18 2356 get_order((nr_pages - nr_reclaimed) * PAGE_SIZE))) {
b5db553cc19549 Zhongkun He 2025-06-18 2357 nr_retries = MAX_RECLAIM_RETRIES;
b5db553cc19549 Zhongkun He 2025-06-18 2358 goto retry;
b5db553cc19549 Zhongkun He 2025-06-18 2359 }
b5db553cc19549 Zhongkun He 2025-06-18 2360
b5db553cc19549 Zhongkun He 2025-06-18 2361 out:
b5db553cc19549 Zhongkun He 2025-06-18 2362 css_put(&memcg->css);
b5db553cc19549 Zhongkun He 2025-06-18 2363 }
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
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