Messages in this thread | | | Date | Tue, 25 Mar 1997 14:40:27 -0400 (AST) | From | William Burrow <> | Subject | Re: output of `free` |
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On Tue, 25 Mar 1997 bofh@snoopy.virtual.net.au wrote:
> Here's the output of running `free` on one of my systems (2.1.29). Is it right to have more shared memory than physical RAM? A quick inspection of the kernel source indicates that the code goes through a map of physical RAM and counts pages, therefore shared should be less than total RAM (the machine has 32megs). Is something wrong or am I misunderstanding this? > > total used free shared buffers cached > Mem: 30760 30360 400 54084 188 2544 > -/+ buffers: 27628 3132 > Swap: 127004 7248 119756
My limited, non-expert understanding of this is that every process gets its shared memory region counted. This implies that shared memory can be larger than actual memory. ie, given the following:
process shared region and size
1 A (300K) 2 A 3 A 4 B (500K) 5 B
The total shared memory shown in free is 3*A + 2*B = 1900K.
Actually, I am interested in uncovering another number concerning ramdisks: the actual amount of memory dedicated to ramdisk or ramdisk like memory (my understanding is that ramdisk pages are a specially marked page).
This is interesting if one is operating a number of ramdisks, and one would like to know how much memory is actually available for processes before assuming that free+buffers means anything useful.
Oh, yeah, thanks to whomever replied to my plea for help on initrd... it sparked a thought in my head (dangerous, I know) and I detected my problem: real-root-dev was not receiving a value it liked from /linuxrc, so it defaulted to /dev/fd0, ho hum.
-- William Burrow -- Fredericton Area Network, New Brunswick, Canada Copyright 1997 William Burrow "Well, let's just say, 'if your VCR is still blinking 12:00, you don't want Linux'". --Bruce Perens, Debian's Fearless Leader ** Those who send MAKE.MONEY.QUICK mail, should be sent to Albania. **
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