From: xu xin <xu.xin16@zte.com.cn>

Users can obtain ksm_profit of a cgroup just by:

    'cat /sys/fs/cgroup/memory.stat | grep ksm_profit

Signed-off-by: xu xin <xu.xin16@zte.com.cn>
---
 mm/ksm.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/mm/ksm.c b/mm/ksm.c
index 4cc47ad1e887..c01567a3d5ca 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -3308,11 +3308,18 @@ long ksm_process_profit(struct mm_struct *mm)
 }
 #endif /* CONFIG_PROC_FS */

+static inline long ksm_general_profit(void)
+{
+	return (ksm_pages_sharing + atomic_long_read(&ksm_zero_pages)) * PAGE_SIZE -
+		ksm_rmap_items * sizeof(struct ksm_rmap_item);
+}
+
 #ifdef CONFIG_MEMCG
 struct memcg_ksm_stat {
 	unsigned long ksm_rmap_items;
 	long ksm_zero_pages;
 	unsigned long ksm_merging_pages;
+	long ksm_profit;
 };

 static int evaluate_memcg_ksm_stat(struct task_struct *task, void *arg)
@@ -3325,6 +3332,7 @@ static int evaluate_memcg_ksm_stat(struct task_struct *task, void *arg)
 		ksm_stat->ksm_rmap_items += mm->ksm_rmap_items;
 		ksm_stat->ksm_zero_pages += mm_ksm_zero_pages(mm);
 		ksm_stat->ksm_merging_pages += mm->ksm_merging_pages;
+		ksm_stat->ksm_profit += ksm_process_profit(mm);
 		mmput(mm);
 	}

@@ -3342,11 +3350,13 @@ void memcg_stat_ksm_show(struct mem_cgroup *memcg, struct seq_buf *s)
 		ksm_stat.ksm_zero_pages = atomic_long_read(&ksm_zero_pages);
 		ksm_stat.ksm_merging_pages = ksm_pages_shared +
 					     ksm_pages_sharing;
+		ksm_stat.ksm_profit = ksm_general_profit();
 	} else {
 		/* Initialization */
 		ksm_stat.ksm_rmap_items = 0;
 		ksm_stat.ksm_zero_pages = 0;
 		ksm_stat.ksm_merging_pages = 0;
+		ksm_stat.ksm_profit = 0;
 		/* Summing all processes'ksm statistic items */
 		mem_cgroup_scan_tasks(memcg, evaluate_memcg_ksm_stat, &ksm_stat);
 	}
@@ -3354,6 +3364,7 @@ void memcg_stat_ksm_show(struct mem_cgroup *memcg, struct seq_buf *s)
 	seq_buf_printf(s, "ksm_rmap_items %lu\n", ksm_stat.ksm_rmap_items);
 	seq_buf_printf(s, "ksm_zero_pages %lu\n", ksm_stat.ksm_zero_pages);
 	seq_buf_printf(s, "ksm_merging_pages %lu\n", ksm_stat.ksm_merging_pages);
+	seq_buf_printf(s, "ksm_profit %lu\n", ksm_stat.ksm_profit);
 }
 #endif

@@ -3648,12 +3659,7 @@ KSM_ATTR_RO(ksm_zero_pages);
 static ssize_t general_profit_show(struct kobject *kobj,
 				   struct kobj_attribute *attr, char *buf)
 {
-	long general_profit;
-
-	general_profit = (ksm_pages_sharing + atomic_long_read(&ksm_zero_pages)) * PAGE_SIZE -
-				ksm_rmap_items * sizeof(struct ksm_rmap_item);
-
-	return sysfs_emit(buf, "%ld\n", general_profit);
+	return sysfs_emit(buf, "%ld\n", ksm_general_profit());
 }
 KSM_ATTR_RO(general_profit);

-- 
2.25.1

Hi,

kernel test robot noticed the following build errors:

[auto build test ERROR on akpm-mm/mm-everything]
[also build test ERROR on tj-cgroup/for-next linus/master v6.17-rc5 next-20250912]
[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/xu-xin16-zte-com-cn/memcg-add-per-memcg-ksm_rmap_items-stat/20250914-181132
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20250914180750448qMRz3iTon78DoExPyZusD%40zte.com.cn
patch subject: [PATCH v2 4/5] memcg: add per-memcg ksm_profit
config: um-randconfig-001-20250914 (https://download.01.org/0day-ci/archive/20250914/202509142046.QatEaTQV-lkp@intel.com/config)
compiler: clang version 22.0.0git (https://github.com/llvm/llvm-project 21857ae337e0892a5522b6e7337899caa61de2a6)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250914/202509142046.QatEaTQV-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/oe-kbuild-all/202509142046.QatEaTQV-lkp@intel.com/

All errors (new ones prefixed by >>):

   /usr/bin/ld: warning: .tmp_vmlinux1 has a LOAD segment with RWX permissions
   /usr/bin/ld: mm/ksm.o: in function `evaluate_memcg_ksm_stat':
>> mm/ksm.c:3335:(.ltext+0x163d): undefined reference to `ksm_process_profit'
   clang: error: linker command failed with exit code 1 (use -v to see invocation)


vim +3335 mm/ksm.c

  3324	
  3325	static int evaluate_memcg_ksm_stat(struct task_struct *task, void *arg)
  3326	{
  3327		struct mm_struct *mm;
  3328		struct memcg_ksm_stat *ksm_stat = arg;
  3329	
  3330		mm = get_task_mm(task);
  3331		if (mm) {
  3332			ksm_stat->ksm_rmap_items += mm->ksm_rmap_items;
  3333			ksm_stat->ksm_zero_pages += mm_ksm_zero_pages(mm);
  3334			ksm_stat->ksm_merging_pages += mm->ksm_merging_pages;
> 3335			ksm_stat->ksm_profit += ksm_process_profit(mm);
  3336			mmput(mm);
  3337		}
  3338	
  3339		return 0;
  3340	}
  3341	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki