[RESEND][PATCH v2 2/2] powerpc/fadump: parse fadump reserve memory size based on memory range
hbathini at linux.vnet.ibm.com
Mon Aug 8 18:15:50 AEST 2016
On Friday 05 August 2016 12:23 AM, Hari Bathini wrote:
> On Thursday 04 August 2016 03:15 PM, Michael Ellerman wrote:
>> Hari Bathini <hbathini at linux.vnet.ibm.com> writes:
>>> * fadump_calculate_reserve_size(): reserve variable boot area 5%
>>> of System RAM
>>> @@ -212,12 +262,17 @@ static inline unsigned long
>>> unsigned long size;
>>> + /* sets fw_dump.reserve_bootvar */
>>> + parse_fadump_reserve_mem();
>>> * Check if the size is specified through fadump_reserve_mem=
>>> * option. If yes, then use that.
>>> if (fw_dump.reserve_bootvar)
>>> return fw_dump.reserve_bootvar;
>>> + else
>>> + printk(KERN_INFO "fadump: calculating default boot size\n");
>>> /* divide by 20 to get 5% of value */
>>> size = memblock_end_of_DRAM() / 20;
>> The code already knows how to reserve 5% based on the size of the
>> memory, as long as no commandline parameter is passed. So why can't we
>> just use that logic?
> Hi Michael,
> That is the default value reserved but not a good enough value for
> every case. It is a bit difficult to come up with a robust formula
> that works for every case as new kernel changes could make the
> values obsolete. But it won't be all that difficult to find values that
> work for different memory ranges for a given kernel version.
> Passing that as range based input with "fadump_reserve_mem"
> parameter would work for every memory configuration on a
> given system, which is what this patch is trying to provide..
You want me to add this to the changelog on respin?
More information about the Linuxppc-dev