On Sat, Jan 05, 2019 at 03:39:10PM -0800, Linus Torvalds wrote: > On Sat, Jan 5, 2019 at 3:16 PM Linus Torvalds > <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > > > > It goes back to forever, it looks like. I can't find a reason. > > mincore() was originally added in 2.3.52pre3, it looks like. Around > 2000 or so. But sadly before the BK history. > > And that comment about > > "Later we can get more picky about what "in core" means precisely." > > that still exists above mincore_page() goes back to the original patch. FreeBSD claims to have a manpage from SunOS 4.1.3 with mincore (!) https://www.freebsd.org/cgi/man.cgi?query=mincore&apropos=0&sektion=0&manpath=SunOS+4.1.3&arch=default&format=html DESCRIPTION mincore() returns the primary memory residency status of pages in the address space covered by mappings in the range [addr, addr + len). The status is returned as a char-per-page in the character array referenced by *vec (which the system assumes to be large enough to encompass all the pages in the address range). The least significant bit of each character is set to 1 to indicate that the referenced page is in pri- mary memory, 0 if it is not. The settings of other bits in each char- acter is undefined and may contain other information in the future.
