Revert "mm/page_cache_limit: create kernel thread for page cache limit"

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4HOXK
CVE: NA

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

This reverts commit b072a9d4.
This feature will be reimplement.
Signed-off-by: NChen Wandun <chenwandun@huawei.com>
Reviewed-by: NTong Tiangen <tongtiangen@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

mm/page_cache_limit.c

 #include <linux/mm.h>
 #include <linux/sysctl.h>
-#include <linux/freezer.h>
-#include <linux/kthread.h>
-#include <linux/module.h>
-#include <linux/err.h>
 
 int pagecache_reclaim_enable;
 int pagecache_limit_ratio;
@@ -11,8 +7,6 @@ int pagecache_reclaim_ratio;
 
 static unsigned long pagecache_limit_pages;
 static unsigned long node_pagecache_limit_pages[MAX_NUMNODES];
-static wait_queue_head_t *pagecache_limitd_wait_queue[MAX_NUMNODES];
-static struct task_struct *pagecache_limitd_tasks[MAX_NUMNODES];
 
 static unsigned long get_node_total_pages(int nid)
 {
@@ -55,130 +49,3 @@ int proc_page_cache_limit(struct ctl_table *table, int write,
 
 	return ret;
 }
-
-void kpagecache_limitd_stop(int nid)
-{
-	if (nid < 0 || nid >= MAX_NUMNODES)
-		return;
-
-	if (pagecache_limitd_tasks[nid]) {
-		kthread_stop(pagecache_limitd_tasks[nid]);
-		pagecache_limitd_tasks[nid] = NULL;
-	}
-
-	if (pagecache_limitd_wait_queue[nid]) {
-		kvfree(pagecache_limitd_wait_queue[nid]);
-		pagecache_limitd_wait_queue[nid] = NULL;
-	}
-}
-
-static void wakeup_kpagecache_limitd(int nid)
-{
-	if (!pagecache_limitd_wait_queue[nid])
-		return;
-
-	if (!waitqueue_active(pagecache_limitd_wait_queue[nid]))
-		return;
-
-	wake_up_interruptible(pagecache_limitd_wait_queue[nid]);
-}
-
-static bool pagecache_overlimit(void)
-{
-	unsigned long total_pagecache;
-
-	total_pagecache = global_node_page_state(NR_FILE_PAGES);
-	total_pagecache -= global_node_page_state(NR_SHMEM);
-
-	return total_pagecache > pagecache_limit_pages;
-}
-
-void wakeup_all_kpagecache_limitd(void)
-{
-	int nid;
-
-	if (!pagecache_reclaim_enable || !pagecache_overlimit())
-		return;
-
-	for_each_node_state(nid, N_MEMORY)
-		wakeup_kpagecache_limitd(nid);
-}
-
-static void shrink_page_cache(void)
-{
-	if (!pagecache_overlimit())
-		return;
-}
-
-static DECLARE_COMPLETION(setup_done);
-static int pagecache_limitd(void *arg)
-{
-	DEFINE_WAIT(wait);
-	int nid = *(int *)arg;
-
-	if (nid < 0 || nid >= MAX_NUMNODES)
-		nid = numa_node_id();
-
-	complete(&setup_done);
-	set_freezable();
-	for (;;) {
-		try_to_freeze();
-		shrink_page_cache();
-
-		prepare_to_wait(pagecache_limitd_wait_queue[nid], &wait,
-				TASK_INTERRUPTIBLE);
-		if (kthread_should_stop())
-			break;
-		schedule();
-		finish_wait(pagecache_limitd_wait_queue[nid], &wait);
-	}
-
-	finish_wait(pagecache_limitd_wait_queue[nid], &wait);
-
-	return 0;
-}
-
-int kpagecache_limitd_run(int nid)
-{
-	int ret = 0;
-	wait_queue_head_t *queue_head = NULL;
-
-	if (pagecache_limitd_tasks[nid] && pagecache_limitd_wait_queue[nid])
-		return 0;
-
-	queue_head = kvmalloc(sizeof(wait_queue_head_t), GFP_KERNEL);
-	if (!queue_head)
-		return -ENOMEM;
-
-	init_waitqueue_head(queue_head);
-	pagecache_limitd_wait_queue[nid] = queue_head;
-	pagecache_limitd_tasks[nid] = kthread_run(pagecache_limitd,
-			(void *)&nid, "kpagecache_limitd%d", nid);
-
-	if (IS_ERR(pagecache_limitd_tasks[nid])) {
-		BUG_ON(system_state < SYSTEM_RUNNING);
-		ret = PTR_ERR(pagecache_limitd_tasks[nid]);
-		pr_err("Failed to start pagecache_limitd on node %d\n", nid);
-		pagecache_limitd_tasks[nid] = NULL;
-		kvfree(queue_head);
-	} else
-		wait_for_completion(&setup_done);
-
-	return ret;
-}
-
-static int __init kpagecache_limitd_init(void)
-{
-	int nid;
-	int ret;
-
-	for_each_node_state(nid, N_MEMORY) {
-		ret = kpagecache_limitd_run(nid);
-		if (ret == -ENOMEM)
-			break;
-	}
-
-	return 0;
-}
-
-module_init(kpagecache_limitd_init);