Re: [PATCH v6 09/24] x86/resctrl: Use set_bit()/clear_bit() instead of open coding

James Morse
2023-10-05T17:31:09Z

Hi Babu,

On 04/10/2023 21:38, Moger, Babu wrote:
> On 9/14/23 12:21, James Morse wrote:
>> The resctrl CLOSID allocator uses a single 32bit word to track which
>> CLOSID are free. The setting and clearing of bits is open coded.
>>
>> A subsequent patch adds resctrl_closid_is_free(), which adds more open
>> coded bitmaps operations. These will eventually need changing to use
>> the bitops helpers so that a CLOSID bitmap of the correct size can be
>> allocated dynamically.
>>
>> Convert the existing open coded bit manipulations of closid_free_map
>> to use set_bit() and friends.

>> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> index ac1a6437469f..fa449ee0d1a7 100644
>> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> @@ -106,7 +106,7 @@ void rdt_staged_configs_clear(void)
>> * - Our choices on how to configure each resource become progressively more
>> * limited as the number of resources grows.
>> */
>> -static int closid_free_map;
>> +static unsigned long closid_free_map;
>> static int closid_free_map_len;
>>
>> int closids_supported(void)
>> @@ -126,7 +126,7 @@ static void closid_init(void)
>> closid_free_map = BIT_MASK(rdt_min_closid) - 1;
>>
>> /* CLOSID 0 is always reserved for the default group */
>> - closid_free_map &= ~1;
>> + clear_bit(0, &closid_free_map);
>
> How about using RESCTRL_RESERVED_CLOSID instead of 0 here?

Great idea - even more readable.

Thanks,

James