How do I install vmtouch on Slackware?

[mgutt]

Sadly I'm not able to find a tgz package and I don't know how to build one.

[mgutt]

Ok, I'm not sure if this is the correct way, but I did the following:

cd /tmp
# deb2tgz
wget https://packages.slackonly.com/pub/packages/14.2-x86_64/misc/deb2tgz/deb2tgz-0.2-noarch-1_slonly.txz
upgradepkg --install-new deb2tgz-0.2-noarch-1_slonly.txz
# ar (needed by deb2tgz)
wget http://slackware.cs.utah.edu/pub/slackware/slackware64-14.2/slackware64/d/binutils-2.26-x86_64-3.txz
upgradepkg --install-new binutils-2.26-x86_64-3.txz
# download vmtouch deb package
wget http://archive.ubuntu.com/ubuntu/pool/universe/v/vmtouch/vmtouch_1.3.1-1_amd64.deb
# deb to tgz conversion
deb2tgz "vmtouch_1.3.1-1_amd64.deb"
# install vmtouch
upgradepkg --install-new vmtouch_1.3.1-1_amd64.txz

Sources:
https://slackware.pkgs.org/14.2/slackonly-x86_64/deb2tgz-0.2-noarch-1_slonly.txz.html
https://slackware.pkgs.org/14.2/slackware-x86_64/binutils-2.26-x86_64-3.txz.html
https://ubuntu.pkgs.org/20.04/ubuntu-universe-amd64/vmtouch_1.3.1-1_amd64.deb.html

[mgutt]

Hmm. Seems not to work (RAM usage was extremely high, too)

vmtouch -v -d -l "/mnt/user/movies/file.mkv"

vmtouch -v -t -p -60M "/mnt/user/movies/file.mkv"
/mnt/user/movies/file.mkv
[OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO] 15360/15360

           Files: 1
     Directories: 0
   Touched Pages: 15360 (60M)
         Elapsed: 0.019109 seconds

vmtouch "/mnt/user/movies/file.mkv"
           Files: 1
     Directories: 0
  Resident Pages: 0/6207469  0/23G  0%
         Elapsed: 2.5259 seconds

[hoytech]

I'm not sure exactly the process on slackware, but if it's running and you're seeing output I guess it installed correctly.

Can you please expand on why you don't believe it's working? The first command looks like you are trying to lock a 23G file in memory? And you are then checking if the first 60M are resident (which it seems they are?).

[mgutt]

why you don't believe it's working

I don't know why, but now it works. I'm not sure how, but I think I triggered a race condition somehow while testing different variantes of the command while the daemon was still crawling the file. Sadly I'm not able to reproduce it. The final result was as you see it above. Although I executed different commands, the last command returned "Resident Pages: 0/6207469 0/23G 0%" which should be "100%" or at least return the "60M" of the second command.

EDIT: Hmm.. this is strange, too:

vmtouch "/mnt/disk1/Movie/OP"
           Files: 213
     Directories: 137
  Resident Pages: 13053541/850054462  49G/3242G  1.54%
         Elapsed: 13.49 seconds

As you can see 49G is in the page cache.

Now I lock it:
vmtouch -v -d -l -m 60M "/mnt/disk1/Movie/OP"

But of 62GiB are still 60GiB available:

free -h
              total        used        free      shared  buff/cache   available
Mem:           62Gi       927Mi       623Mi       818Mi        61Gi        60Gi
Swap:         127Gi        22Mi       127Gi

Isn't it possible to lock files that are already present in the RAM? Let's test it by emptying the cache:
sync; echo 1 > /proc/sys/vm/drop_caches

Status after cache cleaning:

vmtouch "/mnt/disk1/Movie/OP"
           Files: 213
     Directories: 137
  Resident Pages: 386/850054462  1M/3242G  4.54e-05%
         Elapsed: 12.575 seconds

Repeat crawl:
vmtouch -v -d -l -m 60M "/mnt/disk1/Movie/OP"

Check after some minutes:

vmtouch "/mnt/disk1/Movie/OP"
           Files: 213
     Directories: 137
  Resident Pages: 386/850054462  1M/3242G  4.54e-05%
         Elapsed: 12.488 seconds

Ok, now I'm confused ^^ Let's try with -p:
vmtouch -v -d -l -p 0M-60M "/mnt/disk1/Movie/OP"

vmtouch "/mnt/disk1/Movie/OP"
           Files: 213
     Directories: 137
  Resident Pages: 2247618/850054462  8G/3242G  0.264%
         Elapsed: 12.957 seconds

Ok, this command works and the crawled file parts were locked as well:

ps aux | awk '{print $6/1024 " MB\t\t" $11}' | sort -n | grep vmtouch
2.63672 MB              vmtouch
2.83594 MB              vmtouch
8761.03 MB              vmtouch

And I think I found another problem. This command crawls the complete file:
vmtouch -v -d -l "/mnt/user/movies/file.mkv"

Shoudn't it crawl only "500M" as mentioned in the manual?

-m <max file size>
Maximum file size to map into virtual memory. Files that are larger than this will be skipped. Examples: 4096, 4k, 100M, 1.5G. The default is 500M.

[hoytech]

Shoudn't it crawl only "500M" as mentioned in the manual?

No, -m is supposed to entirely skip files larger than this amount (by default).

I suggest not using the daemon mode during testing, it's easy to forget you have one running.

[mgutt]

skip files larger than this amount

Ok, makes sense. I mean the manual says "skip". I don't know why I thought about partial crawling. Sorry for that ^^

[mgutt]

deleted

[hoytech]

No worries. -m was sort of hack in the first place. People would accidentally crawl a directory with a gigantic file in it and it would grind their system to a halt. The 500M was totally arbitrary. Maybe this flag is unnecessary now.