On Thu, Jul 20, 2017 at 11:53:16PM +0200, Christoph Anton Mitterer wrote: > On Thu, 2017-07-20 at 14:48 -0700, Omar Sandoval wrote: > > Just to be sure, did you explicitly write 0 to these? > Nope... that seemed to have been the default value, i.e. I used > sysctl(8) in read (and not set) mode here.
Okay, all good then. > > These sysctls are > > really confusing, see https://www.kernel.org/doc/Documentation/sysctl > > /vm.txt. > > Basically, there are two ways to specify these, either as a ratio of > > system memory (vm.dirty_ratio and vm.dirty_background_ratio) or a > > static > > number of bytes (vm.dirty_bytes and vm.dirty_background_bytes). If > > you > > set one, the other appears as 0, and the kernel sets the ratios by > > default. But if you explicitly set them to 0, the kernel is going to > > flush stuff extremely aggressively. > I see,... not sure why both are 0 here... at least I didn't change it > myself - must be something from the distro? That's normal, the default is to have the ratio set instead: $ sysctl vm.dirty_{,background_}{bytes,ratio} vm.dirty_bytes = 0 vm.dirty_ratio = 20 vm.dirty_background_bytes = 0 vm.dirty_background_ratio = 10 > > Awesome, glad to hear it! I hadn't been able to reproduce the issue > > outside of Facebook. Can I add your tested-by? > Sure, but better use my other mail address for it, if you don't mind: > Christoph Anton Mitterer <m...@christoph.anton.mitterer.name> No problem. I'll resend the patch with that shortly. > > > I assume you'll take care to get that patch into stable kernels? > > > Is this patch alone enough to recommend the Debian maintainers to > > > include it into their 4.9 long term stable kernels? > > > > I'll mark it for stable, assuming Debian tracks the upstream LTS > > releases it should get in. > Okay :-) > > Nevertheless I'll open a bug at their BTS, just to be safe. > > > Thanks :) > > Chris. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
