Please explain Linux memory usage

DIGITAL39 · 12-31-2006, 02:39 AM

I found a post while searching that mentioned Linux uses memory much different than Windows, but it is sorta annoying if that is true. I am running slackware 11 out of the box with a full install. Normal applications running nothing special, not a lot of startup applications and using KDE. I have 1gb of ram and 2gb swap on kernel 2.6.17.13-smp. Here is my meminfo

Code:

MemTotal:      1035496 kB
MemFree:         21508 kB
Buffers:        111864 kB
Cached:         551148 kB
SwapCached:         24 kB
Active:         612228 kB
Inactive:       344540 kB
HighTotal:      131008 kB
HighFree:          260 kB
LowTotal:       904488 kB
LowFree:         21248 kB
SwapTotal:     2000084 kB
SwapFree:      1997364 kB
Dirty:              36 kB
Writeback:           0 kB
Mapped:         362232 kB
Slab:            48416 kB
CommitLimit:   2517832 kB
Committed_AS:   653980 kB
PageTables:       1876 kB
VmallocTotal:   114680 kB
VmallocUsed:      5472 kB
VmallocChunk:   108760 kB

If I have 1gb of RAM and I am only running firefox,gaim,and amarok why I am dipping into my swap? that seems a bit ridiculous to me, but I am hoping someone can help me understand.

Thanks for your help.

Pete

acid_kewpie · 12-31-2006, 03:54 AM

well you've only used 24k of swap, and to be honest i don't know what that's been used for, but it's really neglibile. the cache can be thought of as "free" if it's needed as such. as i've said in a huge number of other posts, it's old data that's no longer used, but *might* be useful in the future. why bother clearing it out when you don't currently need the space? can't see how that's "sorta annoying" in the slightest.

DIGITAL39 · 12-31-2006, 04:09 AM

Thanks acid,

I guess it is annoying because I am not used to it. I am still in a Windows mindset where <20mb of ram matters. If you are saying its cool then it doesnt annoy me because linux will take care of it for me.

syg00 · 12-31-2006, 04:25 AM

Read this. Any further questions just ask.

acid_kewpie · 12-31-2006, 09:20 AM

Quote:

Originally Posted by DIGITAL39

Thanks acid,

I guess it is annoying because I am not used to it. I am still in a Windows mindset where <20mb of ram matters. If you are saying its cool then it doesnt annoy me because linux will take care of it for me.

well, you (presumably) paid good money for that memory, wouldn't you rather the os did *something* with it rather than let it sit twiddling it's thumbs?

Trio3b · 12-31-2006, 03:53 PM

I guess being used to less memory usage to accomplish the "same task" make it appear that the memory management is more efficient. But...if the memory in linux is being kept in standby mode then this is more efficient. Is this what is happening?

Thanks

acid_kewpie · 12-31-2006, 03:59 PM

yep. windows proactively purges unused data from memory. if that space isn't needed at that moment, why bother wasting CPU cycles clearing it all out?