From: Liu Shixin liushixin2@huawei.com

When a task in memcg readaheads file pages, page_cache_ra_unbounded() will try to readahead nr_to_read pages. Even if the new allocated page fails to charge, page_cache_ra_unbounded() still tries to readahead next page. This leads to too much memory reclaim.

Stop readahead if mem_cgroup_charge() fails, i.e. add_to_page_cache_lru() returns -ENOMEM.

Signed-off-by: Liu Shixin liushixin2@huawei.com Signed-off-by: Jinjiang Tu tujinjiang@huawei.com --- mm/readahead.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/mm/readahead.c b/mm/readahead.c index ed23d5dec123..22dd9c8fe808 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -220,11 +220,18 @@ void page_cache_ra_unbounded(struct readahead_control *ractl, if (mapping->a_ops->readpages) { page->index = index + i; list_add(&page->lru, &page_pool); - } else if (add_to_page_cache_lru(page, mapping, index + i, - gfp_mask) < 0) { - put_page(page); - read_pages(ractl, &page_pool, true); - continue; + } else { + int ret; + + ret = add_to_page_cache_lru(page, mapping, index + i, + gfp_mask); + if (ret < 0) { + put_page(page); + read_pages(ractl, &page_pool, true); + if (ret == -ENOMEM) + break; + continue; + } } if (i == nr_to_read - lookahead_size) SetPageReadahead(page);