Messages in this thread | | | Date | Fri, 19 Jun 1998 19:55:13 +0200 (CEST) | From | Rik van Riel <> | Subject | Re: How much kernel stack do we need? |
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On Fri, 19 Jun 1998, Bernd Schmidt wrote:
> In 2.1.x kernels, the kernel stack size is 8192 bytes (2 pages) on the i386, > minus the size of the task structure (around 1000). This means the stack is > more than 3000 bytes larger than in 2.0.x where it used to be one page. My > question is: do we really need this?
This is a _very_ good question, since it could save us one unswappable page _per process_. This might not seem like an awful lot of memory, but with the current fragmentation problems this patch could save our butt... (at least until the zone allocator is ready)
[snip measurements] > that allocate a 2000 byte array on the stack. Does anyone else think it > would be worthwhile to fix those and reduce the kernel stack size again?
Absolutely. Just think about someone running 60 processes on a 4MB machine. This person is now wasting 60 * 4k = 240kB of _unswappable_ memory. That is 1/16th of total memory, which can be very taxing on your router/mailserver.
> I have a patch that makes the stack size configurable (I've even tested it...) > which I could provide if someone is interested.
I am _very_ interested. I'll put it on the Linux MM (http://www.phys.uu.nl/~riel/mm-patch/) immediately!
Rik. +-------------------------------------------------------------------+ | Linux memory management tour guide. H.H.vanRiel@phys.uu.nl | | Scouting Vries cubscout leader. http://www.phys.uu.nl/~riel/ | +-------------------------------------------------------------------+
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