On Fri, Feb 12, 2016 at 08:35:53PM +0100, Andres Freund wrote: > To make an actually usable patch out of this it seems we'd have to add a > 'partial' argument to grab_cache_page_write_begin(), so writes to parts > of a page still cause the pages to be marked active. Is it preferrable > to change all callers of grab_cache_page_write_begin and > add_to_page_cache_lru or make them into wrapper functions, and call the > real deal when it matters? Personally, I'd prefer explicit arguments over another layer of wrappers, especially in the add_to_page_cache family. But it's possible others will disagree and only voice their opinion once you went through the hassle and sent a patch. > I do think that that's a reasonable algorithmic change, but nonetheless > its obviously possible that such changes regress some workloads. What's > the policy around testing such things? How about a FGP_WRITE that only sets the page's referenced bit, but doesn't activate or refault-activate the page? That way, pages that are only ever written would never get activated, but a single read mixed in would activate the page straightaway; either in mark_page_accessed() or through refault-activation. -- 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=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>