> On 07/25/2014 08:06 AM, Wilco Dijkstra wrote: > > Is there a reason Linux does not do background page clearing like other OSes to reduce this > > overhead? It would be a good fit for typical mobile workloads (bursts of high activity > followed by > > periods of low activity). > > If the page is being allocated, it is about to be used and be brought in > to the CPU's cache. If we zero it close to this use, we only pay to > bring it in to the CPU's cache once. Or so goes the theory... I can see the reasoning for 4KB pages and small allocations (eg. stack), but would that ever be true for huge pages? > I tried a zero-on-free implementation a year or so ago. It helped some > workloads and hurt others. The gains were not large enough or > widespread enough to merit pushing it in to the kernel. Was that literally zero-on-free or zero in the background? Was the result the same for different page sizes? My guess is that the result will be different for huge pages. Wilco -- IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you. ARM Limited, Registered office 110 Fulbourn Road, Cambridge CB1 9NJ, Registered in England & Wales, Company No: 2557590 ARM Holdings plc, Registered office 110 Fulbourn Road, Cambridge CB1 9NJ, Registered in England & Wales, Company No: 2548782 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href