linux-kernel - Re: [question] hugetlb: how to find who use hugetlb?

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Date:   Tue, 20 Sep 2016 10:46:04 +0800
From:   Xishi Qiu <qiuxishi@...wei.com>
To:     Linux MM <linux-mm@...ck.org>, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [question] hugetlb: how to find who use hugetlb?

On 2016/9/19 10:39, Xishi Qiu wrote:

> On my system, I set HugePages_Total to 2G(1024 x 2M), and I use 1G hugetlb,
> but the HugePages_Free is not 1G(512 x 2M), it is 280(280 x 2M) left,
> HugePages_Rsvd is 0, it seems someone use 232(232 x 2M) hugetlb additionally.
> 
> So how to find who use the additional hugetlb? 
> 
> I search every process and find the total hugetlb size is only 1G,
> cat /proc/xx/smaps | grep KernelPageSize, then account the vma size
> which KernelPageSize is 2048 kB.
> 
> Thanks,
> Xishi Qiu
> 

I kill the processes which use hugetlb, and set 0 to nr_hugepages.
My kernel version is v3.10

meminfo:
HugePages_Total:     232
HugePages_Free:        0
HugePages_Rsvd:        0
HugePages_Surp:      232
Hugepagesize:       2048 kB

"cat /proc/*/smaps | grep KernelPageSize| grep 2048" shows nothing.

linux-ZSfbIr:/home # mount | grep hugetlb
cgroup on /sys/fs/cgroup/hugetlb type cgroup (rw,nosuid,nodev,noexec,relatime,hugetlb)
hugetlbfs on /dev/hugepages type hugetlbfs (rw,relatime)
nodev on /dev/hugepages type hugetlbfs (rw,relatime)

linux-ZSfbIr:/home # ll /dev/hugepages/
total 0

linux-ZSfbIr:/home # ll /sys/fs/cgroup/hugetlb/
total 0
-rw-r--r-- 1 root root 0 Sep 13 08:10 cgroup.clone_children
--w--w--w- 1 root root 0 Sep 13 08:10 cgroup.event_control
-rw-r--r-- 1 root root 0 Sep 13 08:10 cgroup.procs
-r--r--r-- 1 root root 0 Sep 13 08:10 cgroup.sane_behavior
-rw-r--r-- 1 root root 0 Sep 13 08:10 hugetlb.1GB.failcnt
-rw-r--r-- 1 root root 0 Sep 13 08:10 hugetlb.1GB.limit_in_bytes
-rw-r--r-- 1 root root 0 Sep 13 08:10 hugetlb.1GB.max_usage_in_bytes
-r--r--r-- 1 root root 0 Sep 13 08:10 hugetlb.1GB.usage_in_bytes
-rw-r--r-- 1 root root 0 Sep 13 08:10 hugetlb.2MB.failcnt
-rw-r--r-- 1 root root 0 Sep 13 08:10 hugetlb.2MB.limit_in_bytes
-rw-r--r-- 1 root root 0 Sep 13 08:10 hugetlb.2MB.max_usage_in_bytes
-r--r--r-- 1 root root 0 Sep 13 08:10 hugetlb.2MB.usage_in_bytes
-rw-r--r-- 1 root root 0 Sep 13 08:10 notify_on_release
-rw-r--r-- 1 root root 0 Sep 13 08:10 release_agent
-rw-r--r-- 1 root root 0 Sep 13 08:10 tasks
linux-ZSfbIr:/home #

> 
>