On Tue, Oct 10, 2017 at 10:34:19AM -0400, Doug Ledford wrote: > On 10/10/2017 12:14 AM, Leon Romanovsky wrote: > > On Mon, Oct 09, 2017 at 05:01:33PM +0000, Bart Van Assche wrote: > >> On Mon, 2017-10-09 at 12:56 -0400, Doug Ledford wrote: > >>> On Sun, 2017-10-08 at 13:03 +0300, Leon Romanovsky wrote: > >>>> It is a little bit strange to ask from user to decide if his adapter > >>>> supports SRQ or not. > >>>> > >>>> It should be automatically. > >>> > >>> I think Bart's intent is that the driver not use SRQ as the default > >>> behavior even if the adapter supports it, so querying the adapter for > >>> support and enabling it if it exists would not achieve his desired > >>> result. This would then be used to override that behavior. Is that > >>> correct Bart? > >> > >> Hello Leon and Doug, > >> > >> The changes realized by this patch are: > >> - Instead of using SRQ as default, use non-SRQ mode as default. > >> - If SRQ has been chosen as default, and if SRQ is not supported, fall back > >> to non-SRQ mode (see also the if (IS_ERR(sdev->srq)) ... code). > >> > >> Please let me know if you have any further questions about this patch. > > > > Yes, in case HCA supports SRQ, when do you set that module parameter? > > You set it in your /etc/modprobe.d/ib_srp.conf file or the equivalent in > your OS. Doug, But my question was "when" and not "how". When should I set this parameter to true? > > > In the commit message, you mentioned disadvantages of using SRQ is a > > default and among them - locks contention, which can be changed in the > > future. Won't it mean that users stuck with current default, because > > change of default will "break" their scripts? > > No, it won't. If you change the default, you don't remove the variable, > you just change what its setting is. Then existing modprobe.d files > become redundant, but nothing breaks. People that don't want the new > setting add a new file to the modprobe.d directory to change the option. Not accurate, now I won't set any parameter because I'm relying on the fact that the default is without SRQ. Once the default will be changed, it will break my assumption. > > > Setting visible to user default won't allow us to change SRP behavior in > > the future. > > No it doesn't. > > > I wouldn't recommend to make such option accessible by users. > > > > Thanks > > > >> > >> Bart. > > > -- > Doug Ledford <dledford@xxxxxxxxxx> > GPG Key ID: B826A3330E572FDD > Key fingerprint = AE6B 1BDA 122B 23B4 265B 1274 B826 A333 0E57 2FDD >
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