The pcstat tool can get page cache statistics for one file by the file's name, or all cached files for a process by the process's pid.
However, I often meet with a question: I know os cached memories by cat /proc/meminfo or free, but I can't find out those BIG files which is being cached. Of course I can use the ps aux command to get those processes who used a lot of memory and get the details by the pcstat --pid [pid], but pcstat does not sort the result, and it is not convenient.
So I add a feature to pcstat: you can use the option --top [X] to show the top X biggest cached files globally. After that, you can use lsof to find out the bad guy.
I also build a bin file. You can download it from here, have a try! I have tested it on centos7.2 and ubuntu 16.04.
hcache has the same options that is used by pcstat, and a new option --top [X]. Attention, you CANNOT use both -pid and -top.
hcache <-json <-pps>|-terse|-default> <-nohdr> <-bname> file file file
-json output will be JSON
-pps include the per-page information in the output (can be huge!)
-terse print terse machine-parseable output
-default print ascii tables
-histo print a histogram using unicode block characters
-nohdr don't print the column header in terse or default format
-bname use basename(file) in the output (use for long paths)
-plain return data with no box characters
-unicode return data with unicode box characters
-pid int show all open maps for the given pid
-top int show top x cached files in descending order
$ sudo hcache --top 3
[sudo] password for silenceshell:
+-------------------------------------------------+----------------+-------------+----------------+-------------+---------+
| Name | Size │ Pages │ Cached Size │ Cached Pages│ Percent │
|-------------------------------------------------+----------------+-------------+----------------+-------------+---------|
| /opt/apps/cn.google.chrome/files/chrome | 170.811M | 43728 | 120.652M | 30887 | 70.634 |
| /opt/apps/com.visualstudio.code/files/code/code | 125.409M | 32105 | 92.593M | 23704 | 73.833 |
| /usr/lib/i386-linux-gnu/libLLVM-11.so.1 | 74.384M | 19043 | 48.057M | 12303 | 64.606 |
|-------------------------------------------------+----------------+-------------+----------------+-------------+---------|
│ Sum │ 370.604M │ 94876 │ 261.301M │ 66894 │ 70.507 │
+-------------------------------------------------+----------------+-------------+----------------+-------------+---------+
$
$ sudo ./hcache --top 3 --bname
+-----------------+----------------+-------------+----------------+-------------+---------+
| Name | Size │ Pages │ Cached Size │ Cached Pages│ Percent │
|-----------------+----------------+-------------+----------------+-------------+---------|
| chrome | 170.811M | 43728 | 122.030M | 31240 | 71.442 |
| code | 125.409M | 32105 | 92.913M | 23786 | 74.088 |
| libLLVM-11.so.1 | 74.384M | 19043 | 44.486M | 11389 | 59.807 |
|-----------------+----------------+-------------+----------------+-------------+---------|
│ Sum │ 370.604M │ 94876 │ 259.430M │ 66415 │ 70.002 │
+-----------------+----------------+-------------+----------------+-------------+---------+
$
$ lsof /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4.10.2
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
quiterss 20630 silenceshell mem REG 8,5 36462184 3936610 /usr/lib/x86_64-linux-gnu/libQtWebKit.so.4.10.2
hcache needs go version > 1.12 for go mod
git clone https://github.com/silenceshell/hcache.git
cd hcache
make build
sudo cp hcache /usr/local/bin/
Go 1.4 or higher and golang.org/x/sys/unix.
From the mincore(2) man page:
- Available since Linux 2.3.99pre1 and glibc 2.2.
- mincore() is not specified in POSIX.1-2001, and it is not available on all UNIX implementations.
- Before kernel 2.6.21, mincore() did not return correct information some mappings.
silenceshell
Apache 2.0
@tobert for pcstat and @mitchellh for go-ps