On Mon, 5 Jan 2015 10:41:43 -0800 Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote: > On Wed, Dec 10, 2014 at 09:12:11AM -0500, Matthew Wilcox wrote: > > On Wed, Dec 10, 2014 at 06:03:47AM -0800, Christoph Hellwig wrote: > > > What is the status of this patch set? > > > > I have no outstanding bug reports against it. Linus told me that he > > wants to see it come through Andrew's tree. I have an email two weeks > > ago from Andrew saying that it's on his list. I would love to see it > > merged since it's almost a year old at this point. > > And since then another month and aother merge window has passed. Is > there any way to speed up merging big patch sets like this one? I took a look at dax last time and found it to be unreviewable due to lack of design description, objectives and code comments. Hopefully that's been addressed - I should get back to it fairly soon as I chew through merge window and holiday backlog. > Another one is non-blocking read one that has real life use on one > of the biggest server side webapp frameworks but doesn't seem to make > progress, which is a bit frustrating. I took a look at pread2() as well and I have two main issues: - The patchset includes a pwrite2() syscall which has nothing to do with nonblocking reads and which was poorly described and had little justification for inclusion. - We've talked for years about implementing this via fincore+pread and at least two fincore implementations are floating about. Now along comes pread2() which does it all in one hit. Which approach is best? I expect fincore+pread is simpler, more flexible and more maintainable. But pread2() will have lower CPU consumption and lower average-case latency. But how *much* better is pread2()? I expect the difference will be minor because these operations are associated with a great big cache-stomping memcpy. If the pread2() advantage is "insignificant for real world workloads" then perhaps it isn't the best way to go. I just don't know, and diligence requires that we answer the question. But all I've seen in response to these questions is handwaving. It would be a shame to make a mistake because nobody found the time to perform the investigation. Also, integration of pread2() into xfstests is (or was) happening and the results of that aren't yet known. -- 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>