Linux Kernel 2.2.19 Available Memory Bug
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Hello,
Please note I am not on the Kernel Mailing List so do try to copy me in with any reply, questions, clarifications, confirmations, et al on this bug report.
Before I forget I am using SuSE 6.4 with most of the updates from the base applied, most meaning I generally lag a bit behind at times. I am NOT using the SuSE kernel due to bugs introduced into the SuSE kernel with the SuSE patches/enhancements. I am using the Linus 2.2.19 Kernel with the OpenWall patches. System is AMD K6-2 500 based system. The version of gcc was 2.95.2 to compile the kernel.
The bug I am reporting is that when one sets the amount of memory, i.e. 128M, 256M; at the time of booting the 2.2.19 kernel the "Total Memory" as reported by KDE, "free", etc is short by a important amount. To be more specific I will detail the results of "free" below against the "mem" value passed to the kernel. Please note for the purposes of this test I always had 256MB or ram (2x128MB) installed in my system. The BIOS reports total system memory as 262144K.
"mem=256m"
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KDE reports 251.09 Total System memory, or 263290880 bytes.
"free -m" indicates "Total Memory" as 251
"free -k" indicates "Total Memory" as 257120
"free -k" indicates "Total Memory" as 263290880
The exact same vaules as noted above are indicated for "mem=262144k", and "mem=268435546" (256 X 1024 x 1024).
"mem=128m"
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"free -m" indicates "Total Memory" as 124
"free -k" indicates "Total Memory" as 127344
"free -k" indicates "Total Memory" as 130400256
Regards,
John L. Males
Software I.Q. Consulting
Toronto, Ontario
Canada
20 July 2001 03:47
mailto:[email protected]
mailto:[email protected]
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Quoted 8 lines · John L. Males
The bug I am reporting is that when one sets the amount of memory, i.e. 128M, 256M; at the time of booting the 2.2.19 kernel the "Total Memory" as reported by KDE, "free", etc is short by a important amount. To be more specific I will detail the results of "free" below against the "mem" value passed to the kernel. Please note for the purposes of this test I always had 256MB or ram (2x128MB) installed in my system. The BIOS reports total system memory as 262144K.
Not really a bug--the "free" report leaves out the memory devoted to the kernel, which is unpageable and therefore unavailable to user apps.
-Doug
Signature · 4 lines
The rain man gave me two cures; he said jump right in, The first was Texas medicine--the second was just railroad gin, And like a fool I mixed them, and it strangled up my mind, Now people just get uglier, and I got no sense of time... --Dylan