On Thu, Feb 25, 2021 at 08:44:17AM +1100, Dave Chinner wrote: > > Also, do you have any idea what was Christoph talking about wrt devices > > with no-op flushes the last time this patch was posted? This change > > seems straightforward to me (assuming the answers to my two question are > > 'yes') but I didn't grok what subtlety he was alluding to...? > > He was wondering what devices benefited from this. It has no impact > on highspeed devices that do not require flushes/FUA (e.g. high end > intel optane SSDs) but those are not the devices this change is > aimed at. There are no regressions on these high end devices, > either, so they are largely irrelevant to the patch and what it > targets... I don't think it is that simple. Pretty much every device aimed at enterprise use does not enable a volatile write cache by default. That also includes hard drives, arrays and NAND based SSDs. Especially for hard drives (or slower arrays) the actual I/O wait might matter. What is the argument against making this conditional?
