Memory Mangement Problem in 5.1-RELEASE

Poul-Henning Kamp phk at
Sat Jul 26 01:04:36 PDT 2003

In message <Law14-F97JswFCHOzyf0000896a at>, "Ahmed Al-Hindawi" writes
>>If your system is spending a lot of time moving data to and from swap when 
>>it is not memory-starved, or if it is stalling memory allocations that it 
>>should be able to fulfill from free RAM, that's a concern.
>That is exactly it. I emphaises th words " when it is not memory-starved ". 
>It isn't memory starved.
>Also I get 150Mb frequently of swap disk space, whilst still having a 
>complete third of my memory free!!
>I can understand everyones view on this, that the swap algorithim is swaping 
>pre-emtively. But 150MB?? Is that what is called a low level of swaping??

Programs like cp(1) uses mmap(2) to copy things, so if you cp(1) a big
file, it is not uncommon for some programs to end up on swap.  Until they
are used again, they will not get paged in.  I often see the getty's for
the vty's and similar junk on my swap space.

Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

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