On Tue, 23 Nov 2010 16:16:55 +0900 (JST), KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> wrote: > > By Other approach, app developer uses POSIX_FADV_DONTNEED. > > But it has a problem. If kernel meets page is writing > > during invalidate_mapping_pages, it can't work. > > It is very hard for application programmer to use it. > > Because they always have to sync data before calling > > fadivse(..POSIX_FADV_DONTNEED) to make sure the pages could > > be discardable. At last, they can't use deferred write of kernel > > so that they could see performance loss. > > (http://insights.oetiker.ch/linux/fadvise.html) > > If rsync use the above url patch, we don't need your patch. > fdatasync() + POSIX_FADV_DONTNEED should work fine. > This is quite true, but the patch itself is fairly invasive and unnecessarily so which makes it unsuitable for merging in the eyes of the rsync maintainers (not that I can blame them). This is by no fault of its author; using fadvise is just far harder than it should be. - Ben -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>