Recently, when install package in a docker which almost reached its memory limit, the installer has no respond severely for more than 15 minutes. During this period, I/O stays high(~1G/s) and influence the whole machine. I've constructed a use case as follows: 1. create a docker: $ cat test.sh #!/bin/bash docker rm centos7 --force docker create --name centos7 --memory 4G --memory-swap 6G centos:7 /usr/sbin/init docker start centos7 sleep 1 docker cp ./alloc_page centos7:/ docker cp ./reproduce.sh centos7:/ docker exec -it centos7 /bin/bash 2. try reproduce the problem in docker: $ cat reproduce.sh #!/bin/bash while true; do flag=$(ps -ef | grep -v grep | grep alloc_page| wc -l) if [ "$flag" -eq 0 ]; then /alloc_page & fi sleep 30 start_time=$(date +%s) yum install -y expect > /dev/null 2>&1 end_time=$(date +%s) elapsed_time=$((end_time - start_time)) echo "$elapsed_time seconds" yum remove -y expect > /dev/null 2>&1 done $ cat alloc_page.c: #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <string.h> #define SIZE 1*1024*1024 //1M int main() { void *addr = NULL; int i; for (i = 0; i < 1024 * 6 - 50;i++) { addr = (void *)malloc(SIZE); if (!addr) return -1; memset(addr, 0, SIZE); } sleep(99999); return 0; } We found that this problem is caused by a lot ot meaningless read-ahead. Since the docker is almost met memory limit, the page will be reclaimed immediately after read-ahead and will read-ahead again immediately. The program is executed slowly and waste a lot of I/O resource. These patches aim to break the read-ahead in above scenario. Liu Shixin (2): mm/readahead: break read-ahead loop if filemap_add_folio return -ENOMEM mm/readahead: don't decrease mmap_miss when folio has workingset flags mm/filemap.c | 9 ++++++++- mm/readahead.c | 17 ++++++++++++----- 2 files changed, 20 insertions(+), 6 deletions(-) -- 2.25.1