mm: make page cache use reliable memory by default

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

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

__page_cache_alloc is used to alloc page cache in most file system,
such as ext4, f2fs, so add ___GFP_RELIABILITY flag to support feature
CONFIG_MEMORY_RELIABLE when alloc page.
Signed-off-by: NChen Wandun <chenwandun@huawei.com>
Reviewed-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

include/linux/pagemap.h

@@ -249,6 +249,7 @@ extern struct page *__page_cache_alloc(gfp_t gfp);
 #else
 static inline struct page *__page_cache_alloc(gfp_t gfp)
 {
+	gfp |= ___GFP_RELIABILITY;
 	return alloc_pages(gfp, 0);
 }
 #endif

mm/filemap.c

@@ -1042,6 +1042,7 @@ struct page *__page_cache_alloc(gfp_t gfp)
 	int n;
 	struct page *page;
 
+	gfp |= ___GFP_RELIABILITY;
 	if (cpuset_do_page_mem_spread()) {
 		unsigned int cpuset_mems_cookie;
 		do {