Re: [PATCH] mm/mincore: allow for making sys_mincore() privileged
From: Matthew Wilcox <willy@infradead.org>
Date: 2019-01-06 00:11:46
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linux-mm, lkml
On Sat, Jan 05, 2019 at 03:39:10PM -0800, Linus Torvalds wrote:
On Sat, Jan 5, 2019 at 3:16 PM Linus Torvalds [off-list ref] wrote:quoted
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.