lkml.org 
[lkml]   [2017]   [Jan]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 10/21] MIPS memblock: Discard bootmem allocator initialization
From
Date
Hi Serge,

On 19.12.2016 03:07, Serge Semin wrote:
> Bootmem allocator initialization needs to be discarded.
> PFN limit constants are still in use by some subsystems, so they
> need to be properly initialized. The initialization is moved into
> a separate method and performed with help of commonly used
> platform-specific constants. It might me too simplified, but most
> of the kernel platforms do it the same way. Moreover it's much
> easier to debug it, when it's not that complicated.
>
> Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
> ---
> arch/mips/kernel/setup.c | 193 ++++-------------------------
> 1 file changed, 21 insertions(+), 172 deletions(-)
>
> diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
> index e746793..6562f55 100644
> --- a/arch/mips/kernel/setup.c
> +++ b/arch/mips/kernel/setup.c
> @@ -626,6 +626,25 @@ static void __init request_crashkernel(struct resource *res) { }
> #endif /* !CONFIG_KEXEC */
>
> /*
> + * Calcualte PFN limits with respect to the defined memory layout
> + */
> +static void __init find_pfn_limits(void)
> +{
> + phys_addr_t ram_end = memblock_end_of_DRAM();
> +
> + min_low_pfn = ARCH_PFN_OFFSET;
> + max_low_pfn = PFN_UP(HIGHMEM_START);

This doesn't look right - as this may set max_low_pfn to more than the
actual physical memory size. In some cases this might be a serious
problem and it doesn't look like any other platform does that.
Even in MIPS code you can find uses of max_low_pfn that would be
seriously affected by this change (vpe loader with
CONFIG_MIPS_VPE_LOADER_TOM).

> + max_pfn = PFN_UP(ram_end);
> +#ifdef CONFIG_HIGHMEM
> + highstart_pfn = max_low_pfn;
> + highend_pfn = max_pfn <= highstart_pfn ? highstart_pfn : max_pfn;
> +#endif
> + pr_info("PFNs: low min %lu, low max %lu, high start %lu, high end %lu,"
> + "max %lu\n",
> + min_low_pfn, max_low_pfn, highstart_pfn, highend_pfn, max_pfn);
> +}
> +
> +/*
> * Initialize the bootmem allocator. It also setup initrd related data
> * if needed.
> */



I fully agree with you that the current initialisation code is really
complex and difficult to debug, but the modified one seems a bit too
simplified.

Regards,
Marcin

\
 
 \ /
  Last update: 2017-01-23 08:56    [W:0.198 / U:0.652 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site