Messages in this thread | | | Subject | Re: [RESEND][PATCH v2 2/2] powerpc/fadump: parse fadump reserve memory size based on memory range | From | Hari Bathini <> | Date | Mon, 8 Aug 2016 13:45:50 +0530 |
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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@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 >>> fadump_calculate_reserve_size(void) >>> { >>> unsigned long size; >>> + /* sets fw_dump.reserve_bootvar */ >>> + parse_fadump_reserve_mem(); >>> + >>> /* >>> * Check if the size is specified through fadump_reserve_mem= >>> cmdline >>> * 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 >> machine's >> 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.. >
Hi Michael,
You want me to add this to the changelog on respin?
Thanks Hari
> Thanks > Hari > > >> cheers >> >
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