On Tuesday, June 26, 2012 3:41:10 pm Ping Chen wrote: > Hi, > I am a bit confused with all these variables defined in freebsd(especially in freebsd 6.1): Which one of this represents the real memory of a system? Say we bought a system with 4G ram, which one tells me the RAM is 4G? > > Accordign to source code: > > Maxmem ==> the highest page of phisycal address page : if I understand correctly, this is the highest page number of physical memory that is usable? > > realMem --> somehow get assigned by realmem = Maxmem: this is confuing, if they are the same, why bother a realmem variables
I think realMem is legacy. > physmem --> the number of usage pages : this seems the right one extract the memory info, however, it seems system allocate portion of memory to messge buffer which makes this physmem < 4G (assume RAM is 4G) Correct. Note that the firmware can also take up part of RAM as well (e.g. to hold ACPI tables). -- John Baldwin _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "freebsd-hackers-unsubscr...@freebsd.org"
