Date: Tue, 25 Jul 2006 08:54:42 -0400 From: Chuck Swiger <cswiger@mac.com> To: "Michael C. Wu" <keichii@freebsd.org> Cc: freebsd-current@freebsd.org Subject: Re: amd64 page fault situation Message-ID: <44C61492.6020808@mac.com> In-Reply-To: <44C5BBB4.8080102@freebsd.org> References: <44C5BBB4.8080102@freebsd.org>
next in thread | previous in thread | raw e-mail | index | archive | help
Michael C. Wu wrote: > Suppose that there is an op code on amd64 that calls for a 64bit word. > This word crosses a page boundary. i.e. The first byte or 2 of the word > is on the last part of the page, and the second part of the word > is on the next page. > > Do we just have a TLB miss or page miss? If the second part of the opcode is in a page which is resident in physical RAM & present in the TLB, neither. Otherwise the system will query the TLB, and if it doesn't find an entry, it will then scan the page tables. If the entry is found, the CPU will load that entry into the TLB and retry the instruction. If not, that becomes a page fault and the system will have to read in the requested frame of memory from secondary storage and retry the opcode... -- -Chuck
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?44C61492.6020808>