On Tue, May 24, 2016 at 07:07:41PM +0200, Gernot Hillier wrote: > > To me, the problem looks comparable to > https://bugzilla.kernel.org/show_bug.cgi?id=56821 (even if we don't see > a full hang and there's no RAID involved for us), so a closer look on > the SCSI layer or driver might be the next step? What I would suggest is to create a small test case which compares the time it takes to allocate 1 megabyte of memory, zero it, and then write one megabytes of zeros using the write(2) system call. Then try writing one megabytes of zero using the BLKZEROOUT ioctl. I'm pretty sure you'll see same issue with BLKZEROOUT ioctl, but at this point, we'll be able to send bug reports to the SCSI and block layer developers with something that makes this very clear that it has nothing to do with ext4. This way we can also do some differential diagnosis; given that I'm not seeing this complaint from most people, I suspect it will be a matter of adding some specific devices to a blacklist (so that even though the SCSI device claims to support WRITE SAME, we need to disable it because it has a really lousy implementation of the SCSI WRITE SAME command). Cheers, - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
