shmem: Show reliable shmem info

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4SK3S
CVE: NA

------------------------------------------

Add ReliableShmem in /proc/meminfo to show reliable memory info
used by shmem.

- ReliableShmem: reliable memory used by shmem
Signed-off-by: NZhou Guanghui <zhouguanghui1@huawei.com>
Reviewed-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

Documentation/filesystems/proc.txt

@@ -884,6 +884,7 @@ ShmemHugePages:      0 kB
 ShmemPmdMapped:      0 kB
 ReliableTotal:     7340032 kB
 ReliableUsed:       418824 kB
+ReliableShmem:          96 kB
 
 
     MemTotal: Total usable ram (i.e. physical ram minus a few reserved
@@ -976,6 +977,7 @@ VmallocChunk: largest contiguous block of vmalloc area which is free
               allocations. This stat excludes the cost of metadata.
 ReliableTotal: Total reliable memory size
 ReliableUsed:  The used amount of reliable memory
+ReliableShmem: Reliable memory used by shmem
 
 ..............................................................................
 

include/linux/mem_reliable.h

@@ -7,6 +7,7 @@
 #include <linux/mmzone.h>
 #include <linux/mm_types.h>
 #include <linux/sched.h>
+#include <linux/percpu_counter.h>
 
 
 #ifdef CONFIG_MEMORY_RELIABLE
@@ -18,6 +19,7 @@ extern atomic_long_t reliable_user_used_nr_page;
 extern unsigned long task_reliable_limit __read_mostly;
 extern bool reliable_allow_fallback;
 extern bool shmem_reliable;
+extern struct percpu_counter reliable_shmem_used_nr_page;
 
 extern void add_reliable_mem_size(long sz);
 extern void mem_reliable_init(bool has_unmirrored_mem,
@@ -83,6 +85,12 @@ static inline bool shmem_reliable_is_enabled(void)
 	return shmem_reliable;
 }
 
+static inline void shmem_reliable_page_counter(struct page *page, int nr_page)
+{
+	if (shmem_reliable_is_enabled() && page_reliable(page))
+		percpu_counter_add(&reliable_shmem_used_nr_page, nr_page);
+}
+
 #else
 #define reliable_enabled 0
 #define reliable_allow_fb_enabled() false
@@ -114,6 +122,9 @@ static inline void mem_reliable_out_of_memory(gfp_t gfp_mask,
 					      int preferred_nid,
 					      nodemask_t *nodemask) {}
 static inline bool shmem_reliable_is_enabled(void) { return false; }
+static inline void shmem_reliable_page_counter(struct page *page, int nr_page)
+{
+}
 
 #endif
 

mm/mem_reliable.c

@@ -19,6 +19,7 @@ atomic_long_t reliable_user_used_nr_page;
 unsigned long task_reliable_limit = ULONG_MAX;
 bool reliable_allow_fallback __read_mostly = true;
 bool shmem_reliable __read_mostly = true;
+struct percpu_counter reliable_shmem_used_nr_page __read_mostly;
 
 void add_reliable_mem_size(long sz)
 {
@@ -97,7 +98,10 @@ void shmem_reliable_init(void)
 	if (!mem_reliable_is_enabled()) {
 		shmem_reliable = false;
 		pr_info("shmem reliable disabled.\n");
+		return;
 	}
+
+	percpu_counter_init(&reliable_shmem_used_nr_page, 0, GFP_KERNEL);
 }
 
 static unsigned long total_reliable_mem_sz(void)
@@ -124,6 +128,12 @@ void reliable_report_meminfo(struct seq_file *m)
 			   total_reliable_mem_sz() >> 10);
 		seq_printf(m, "ReliableUsed:     %8lu kB\n",
 			   used_reliable_mem_sz() >> 10);
+
+		if (shmem_reliable_is_enabled()) {
+			unsigned long shmem = (unsigned long)percpu_counter_sum(
+				&reliable_shmem_used_nr_page) << (PAGE_SHIFT - 10);
+			seq_printf(m, "ReliableShmem:    %8lu kB\n", shmem);
+		}
 	}
 }
 

mm/shmem.c

@@ -957,6 +957,8 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
 					truncate_inode_page(mapping, page);
 				}
 			}
+			shmem_reliable_page_counter(
+				page, -(1 << compound_order(page)));
 			unlock_page(page);
 		}
 		pagevec_remove_exceptionals(&pvec);
@@ -1067,6 +1069,8 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend,
 					break;
 				}
 			}
+			shmem_reliable_page_counter(
+				page, -(1 << compound_order(page)));
 			unlock_page(page);
 		}
 		pagevec_remove_exceptionals(&pvec);
@@ -1962,6 +1966,7 @@ static int shmem_getpage_gfp(struct inode *inode, pgoff_t index,
 		inode->i_blocks += BLOCKS_PER_PAGE << compound_order(page);
 		shmem_recalc_inode(inode);
 		spin_unlock_irq(&info->lock);
+		shmem_reliable_page_counter(page, 1 << compound_order(page));
 		alloced = true;
 
 		if (PageTransHuge(page) &&