!3582 Add support for memory limit

Merge Pull Request from: @ci-robot 
 
PR sync from: Ze Zuo <zuoze1@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/CHIOHEN5YWFQTIHD2XK7QHCBGELXI26P/ 
To implement this feature, a new function called "shrink_memory" has been
added, which can recycle a specific amount of memory. This feature mainly
supports the following two functions:

1) add periodical memory reclaim
2) add pagecache limit

Above functionalities depend on CONFIG_PAGE_CACHE_LIMIT, and the interface
and functionality tests have been successfully completed.

ChangeLog:
- Some minor changes about description and code, no functional changes
- rename page_cache_shrink_memory to shrink_memory
- move the declaration of the 'shrink_memory' function to 'internal.h',
  no functional changes
- add description information for function "shrink_memory"
- update documentation for using feature alerts

Ze Zuo (2):
  mm: support periodical memory reclaim
  mm: support pagecache limit


-- 
2.25.1
 
https://gitee.com/openeuler/kernel/issues/I8NIKC 
 
Link:https://gitee.com/openeuler/kernel/pulls/3582

 

Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>