Messages in this thread | | | Date | Mon, 16 Jan 2017 17:07:17 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: [PATCH 7/8] x86/intel_rdt/mba: Add schemata file support for MBA |
| |
On Tue, 10 Jan 2017, Vikas Shivappa wrote: > + * @display_str: Format string to show schemata > + * @validate: API to validate the ctrl values. > * @info_files: resctrl info files for the resource > * @infofiles_len: Number of info files > * @max_delay: Max throttle delay > @@ -99,6 +101,9 @@ struct rdt_resource { > int cbm_len; > int min_cbm_bits; > u32 no_ctrl; > + char *display_str; > + int (*validate) (char *buf, unsigned long *data, > + struct rdt_resource *r);
Again this display and validation change wants to be seperate from the bandwidth stuff.
It's not rocket science to split patches into preparatory and implementation parts.
> + r->display_str = kstrdup("%d=%d", GFP_KERNEL); > + if (!r->display_str) > + return -ENOMEM;
And the point of this allocation is? To consume extra memory for a constant string which is in const data anyway.
r->display_str = "%d=%d";
does not need allcotion and consumes exactly the same amount of const data as the above. Oh well...
> -static inline bool get_rdt_resources(void) > +static inline int get_rdt_resources(void) > {
And the point of this change is? Lots of churn to return the same -ENODEV value at the call site. So why are you trying to return other values instead of the simple boolean success/fail decision?
> /* > + * Check whether MBE 'throttle by' value is correct. > + * As per the SDM, when the scale is linear the > + * throttle_by granularity is '100 - max_thrtl_by' > + * and when its non-linear it is 'power of 2'.
That's wrong. We really want to let the user set a bandwidth percentage value from 0 - 100 %. And then adjust it to the proper value which the hardware can provide. So the user value is independent from granularity, linear and the max throttling allowed.
> /* > - * Read one cache bit mask (hex). Check that it is valid for the current > - * resource type. > + * Read the user RDT control value into tempory buffer: > + * Cache bit mask (hex) or Memory b/w throttle (decimal). > + * Check that it is valid for the current resource type. > */ > -static int parse_cbm(char *buf, struct rdt_resource *r) > +static int parse_ctrls(char *buf, struct rdt_resource *r) > { > unsigned long data; > - int ret; > + int ret = 0;
What's the purpose of initializing ret to 0 if the next action is assigning ret the return value of the validate function?
> - ret = kstrtoul(buf, 16, &data); > - if (ret) > - return ret; > - if (!cbm_validate(data, r)) > - return -EINVAL; > + ret = r->validate(buf, &data, r); > r->tmp_ctrl[r->num_tmp_ctrl++] = data; > > - return 0; > + return ret; > }
Thanks,
tglx
| |