Fenghua, > -----Original Message----- > From: [email protected] <linux-kernel- > [email protected]> On Behalf Of Fenghua Yu > Sent: Wednesday, October 31, 2018 4:55 PM > To: Moger, Babu <[email protected]> > Cc: [email protected]; [email protected]; [email protected]; [email protected]; > [email protected]; [email protected]; > [email protected]; [email protected]; akpm@linux- > foundation.org; [email protected]; [email protected]; > [email protected]; [email protected]; > [email protected]; [email protected]; > [email protected]; [email protected]; [email protected]; > [email protected]; [email protected]; > [email protected]; Singh, Brijesh <[email protected]>; Hurwitz, > Sherry <[email protected]>; [email protected]; Lendacky, > Thomas <[email protected]>; [email protected]; [email protected]; > [email protected]; [email protected]; [email protected]; > [email protected]; [email protected]; linux- > [email protected] > Subject: Re: [PATCH v5 00/13] arch/x86: AMD QoS support > > On Thu, Oct 18, 2018 at 10:52:00PM +0000, Moger, Babu wrote: > > Changes from v4 -> v5: > > b. The functions update_mba_bw and set_mba_sc is not required for > AMD. > > Removed all the changes related to these functions. > > Hi, Babu, > > In v4, you says AMD won't support MBA software controller. > > In v5, does AMD support MBA software controller or not? The v5 patches
No, AMD does not support MBA software controller. set_mba_sc will always return -EINVAL on AMD(because delay_linear is set false). That is the reason, I did not add this check. I will add this check in next refresh. Will add Suggested-by you. Thanks > show the feature is supported now. If that's a code bug, you may need > the following patch? > > x86/resctrl: Only Intel RDT supports MBA software controller > > AMD doesn't support the feature. > > Signed-off-by: Fenghua Yu <[email protected]> > > diff --git a/arch/x86/kernel/cpu/resctrl_rdtgroup.c > b/arch/x86/kernel/cpu/resctrl_rdtgroup.c > index 8b6b4a8bb7ca..89dd9b7c9dd7 100644 > --- a/arch/x86/kernel/cpu/resctrl_rdtgroup.c > +++ b/arch/x86/kernel/cpu/resctrl_rdtgroup.c > @@ -1878,9 +1878,11 @@ static int parse_rdtgroupfs_options(char *data) > if (ret) > goto out; > } else if (!strcmp(token, "mba_MBps")) { > - ret = set_mba_sc(true); > - if (ret) > - goto out; > + if (boot_cpu_data.x86_vendor == > X86_VENDOR_INTEL) { > + ret = set_mba_sc(true); > + if (ret) > + goto out; > + } > } else { > ret = -EINVAL; > goto out;
