Arch Linux

workdowg

Member

Registered: 2010-12-31

Posts: 69

x64 kernel reserve size too high?

I'm not really a noob (2yrs on Arch...),  but maybe this question is. (Moderator move where you like..).

I upgraded my x32 system to x64 and now my fresh boot ram use is over ~300mb booted into openbox (~240mb booted to init 3), use to be ~200mb booted into openbox (~140 booted into init 3).

Here are some quick stats (let me know what more you need),

free -m
             total       used       free     shared    buffers     cached
Mem:          3958        879       3079          0         72        388
-/+ buffers/cache:        418       3539
Swap:         3812          0       3812

dmesg|grep Memory
[    0.000000] Memory: 3981824k/4980736k available (4490k kernel code, 787336k absent, 211576k reserved, 4412k data, 736k init)

dmesg|grep TLB
[    1.287810] HugeTLB registered 2 MB page size, pre-allocated 0 pages

Notice the reserve... 212mb seems too high to me. Others have said around 64mb....

Last edited by workdowg (2012-03-18 11:02:21)

graysky

Wiki Maintainer

From: :wq

Registered: 2008-12-01

Posts: 10,734

Website

Re: x64 kernel reserve size too high?

X86_64 will use more ram than i686

---

AUR packages • Zsh and other configs

karol

Archivist

Registered: 2009-05-06

Posts: 25,440

Re: x64 kernel reserve size too high?

https://bbs.archlinux.org/viewtopic.php?id=135309

Edit: Found another user mentioning rather high reserved memory: https://bbs.archlinux.org/viewtopic.php … 21#p857921

Last edited by karol (2012-03-18 12:08:02)

workdowg

Member

Registered: 2010-12-31

Posts: 69

Re: x64 kernel reserve size too high?

https://bbs.archlinux.org/viewtopic.php?id=135309

Edit: Found another user mentioning rather high reserved memory: https://bbs.archlinux.org/viewtopic.php … 21#p857921

I read through those... No real anwers... Maybe I'll just leave this topic open for a while because 212mb still seems way too high.

Edit: Thanks as usual Karol!

Last edited by workdowg (2012-03-18 12:11:29)

karol

Archivist

Registered: 2009-05-06

Posts: 25,440

Re: x64 kernel reserve size too high?

The last post says I/O TLB may account for some of that memory.

Are you using the stock Arch kernel?

workdowg

Member

Registered: 2010-12-31

Posts: 69

Re: x64 kernel reserve size too high?

Yes, I'm using the stock... I could take a shot at a custom compile if that is what your suggesting. Not sure how, but between the wiki and forums I should be ok. I do backups to an external hd with clonezilla. It only takes 30 or so minutes to get back if I break something.

karol

Archivist

Registered: 2009-05-06

Posts: 25,440

Re: x64 kernel reserve size too high?

X86_64 will use more ram than i686

Linux 3.4 has x86 ABI but the 32-bit savings are just in the userspace as the kernel is the good ol' 64-bit binary, from what I gather.