From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nick Piggin Date: Thu, 16 Dec 2004 07:59:34 +0000 Subject: Re: [very very drafty] prezeroing to increase the page fault rate Message-Id: <41C14066.2090203@yahoo.com.au> List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org Christoph Lameter wrote: > On Thu, 16 Dec 2004, Nick Piggin wrote: > >>Would it be possible to just *allocate* the page, zero it, then >>free it, and have it get put onto the zero page list from there? >>If you conceptually think of a page being zeroed as being in use, >>then it would be natural to allocate it...? > > > I tried that. This increases the overhead significantly. Also if you put > back a zeroed page and its going to be merged with its neighbor (likely > not zeroed) then the zero bit has to be dropped. Its then getting a bit > difficult to get zeroed pages into the buddy allocator. > > One could set the zero bit on each individual page but then that increases > again overhead of managing them and checking them. > Hmm, I was thinking 'free' the zeroed page stright onto the pcp zero list. This probably doesn't work well, though, if you want to zero a large proportion of system memory...