Revert "mm: add page cache fallback statistic"

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

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

This reverts commit 925368d8.
Page cache fallback statistic will be replaced by other method.
Signed-off-by: NChen Wandun <chenwandun@huawei.com>
Reviewed-by: NXie XiuQi <xiexiuqi@huawei.com>
Reviewed-by: Kefeng Wang<wangkefeng.wang@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

include/linux/mem_reliable.h

@@ -21,11 +21,9 @@ extern bool reliable_allow_fallback;
 extern bool shmem_reliable;
 extern struct percpu_counter reliable_shmem_used_nr_page;
 extern bool pagecache_use_reliable_mem;
-extern atomic_long_t page_cache_fallback;
 DECLARE_PER_CPU(long, nr_reliable_buddy_pages);
 extern unsigned long nr_reliable_reserve_pages __read_mostly;
 extern long shmem_reliable_nr_page __read_mostly;
-extern void page_cache_fallback_inc(gfp_t gfp, struct page *page);
 
 extern void add_reliable_mem_size(long sz);
 extern void mem_reliable_init(bool has_unmirrored_mem,
@@ -166,7 +164,6 @@ static inline bool shmem_reliable_is_enabled(void) { return false; }
 static inline void shmem_reliable_page_counter(struct page *page, int nr_page)
 {
 }
-static inline void page_cache_fallback_inc(gfp_t gfp, struct page *page) {}
 
 static inline bool pagecache_reliable_is_enabled(void) { return false; }
 static inline bool mem_reliable_status(void) { return false; }

mm/filemap.c

@@ -1050,13 +1050,9 @@ struct page *__page_cache_alloc(gfp_t gfp)
 			page = __alloc_pages_node(n, gfp, 0);
 		} while (!page && read_mems_allowed_retry(cpuset_mems_cookie));
 
-		page_cache_fallback_inc(gfp, page);
 		return page;
 	}
-	page = alloc_pages(gfp, 0);
-	page_cache_fallback_inc(gfp, page);
-
-	return page;
+	return alloc_pages(gfp, 0);
 }
 EXPORT_SYMBOL(__page_cache_alloc);
 #endif

mm/mem_reliable.c

@@ -35,7 +35,6 @@ unsigned long nr_reliable_reserve_pages = MEM_RELIABLE_RESERVE_MIN / PAGE_SIZE;
 long shmem_reliable_nr_page = LONG_MAX;
 
 bool pagecache_use_reliable_mem __read_mostly = true;
-atomic_long_t page_cache_fallback = ATOMIC_LONG_INIT(0);
 DEFINE_PER_CPU(long, pagecache_reliable_pages);
 
 static unsigned long zero;
@@ -57,19 +56,6 @@ bool page_reliable(struct page *page)
 	return mem_reliable_is_enabled() && page_zonenum(page) < ZONE_MOVABLE;
 }
 
-static bool is_fallback_page(gfp_t gfp, struct page *page)
-{
-	bool ret = false;
-
-	if (!page)
-		return ret;
-
-	if ((gfp & ___GFP_RELIABILITY) && !page_reliable(page))
-		ret = true;
-
-	return ret;
-}
-
 static bool reliable_and_lru_check(enum lru_list lru, struct page *page)
 {
 	if (!page || !page_reliable(page))
@@ -89,21 +75,6 @@ void page_cache_reliable_lru_add(enum lru_list lru, struct page *page, int val)
 	this_cpu_add(pagecache_reliable_pages, val);
 }
 
-void page_cache_fallback_inc(gfp_t gfp, struct page *page)
-{
-	long num;
-
-	if (!pagecache_reliable_is_enabled())
-		return;
-
-	if (!is_fallback_page(gfp, page))
-		return;
-
-	num = atomic_long_inc_return(&page_cache_fallback);
-	if (num < 0)
-		atomic_long_set(&page_cache_fallback, 0);
-}
-
 static int reliable_mem_notifier(struct notifier_block *nb,
 				 unsigned long action, void *arg)
 {