linux-kernel - Re: [PATCH] ARM: mm: initialize pfn limits with find

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Date:   Mon, 21 Jan 2019 23:22:10 +0200
From:   Mike Rapoport <rppt@...ux.ibm.com>
To:     Florian Fainelli <f.fainelli@...il.com>
Cc:     Doug Berger <opendmb@...il.com>,
        Russell King <linux@...linux.org.uk>,
        Catalin Marinas <catalin.marinas@....com>,
        Mike Rapoport <rppt@...ux.vnet.ibm.com>,
        Nicolas Pitre <nicolas.pitre@...aro.org>,
        Michal Hocko <mhocko@...e.com>, linux-kernel@...r.kernel.org,
        "Steven Rostedt (VMware)" <rostedt@...dmis.org>,
        Jinbum Park <jinb.park7@...il.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] ARM: mm: initialize pfn limits with find_limits()

On Mon, Jan 21, 2019 at 12:48:09PM -0800, Florian Fainelli wrote:
> On 1/10/19 11:07 AM, Doug Berger wrote:
> > On 12/27/18 3:47 PM, Doug Berger wrote:
> >> The max_low_pfn value must be set before sparse_init() is called to
> >> keep the early memblock allocations and frees balanced for kmemleak
> >> initialization when sparsemem is enabled.
> >>
> >> This commit accomplishes that by replacing the local variables min,
> >> max_low, and max_high with the global limit variables min_low_pfn,
> >> max_low_pfn, and max_pfn respectively in bootmem_init(). The global
> >> variables are initialized directly by find_limits() and used in the
> >> remainder of the function.
> >>
> >> Fixes: 9099daed9c69 ("mm: kmemleak: avoid using __va() on addresses that don't have a lowmem mapping")
> >> Signed-off-by: Doug Berger <opendmb@...il.com>
> >> ---
> >>  arch/arm/mm/init.c | 20 ++++----------------
> >>  1 file changed, 4 insertions(+), 16 deletions(-)
> >>
> >> diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
> >> index 32e4845af2b6..98a733f3a5b9 100644
> >> --- a/arch/arm/mm/init.c
> >> +++ b/arch/arm/mm/init.c
> >> @@ -302,15 +302,12 @@ void __init arm_memblock_init(const struct machine_desc *mdesc)
> >>  
> >>  void __init bootmem_init(void)
> >>  {
> >> -	unsigned long min, max_low, max_high;
> >> -
> >>  	memblock_allow_resize();
> >> -	max_low = max_high = 0;
> >>  
> >> -	find_limits(&min, &max_low, &max_high);
> >> +	find_limits(&min_low_pfn, &max_low_pfn, &max_pfn);
> >>  
> >> -	early_memtest((phys_addr_t)min << PAGE_SHIFT,
> >> -		      (phys_addr_t)max_low << PAGE_SHIFT);
> >> +	early_memtest((phys_addr_t)min_low_pfn << PAGE_SHIFT,
> >> +		      (phys_addr_t)max_low_pfn << PAGE_SHIFT);
> >>  
> >>  	/*
> >>  	 * Sparsemem tries to allocate bootmem in memory_present(),
> >> @@ -328,16 +325,7 @@ void __init bootmem_init(void)
> >>  	 * the sparse mem_map arrays initialized by sparse_init()
> >>  	 * for memmap_init_zone(), otherwise all PFNs are invalid.
> >>  	 */
> >> -	zone_sizes_init(min, max_low, max_high);
> >> -
> >> -	/*
> >> -	 * This doesn't seem to be used by the Linux memory manager any
> >> -	 * more, but is used by ll_rw_block.  If we can get rid of it, we
> >> -	 * also get rid of some of the stuff above as well.
> >> -	 */
> >> -	min_low_pfn = min;
> >> -	max_low_pfn = max_low;
> >> -	max_pfn = max_high;
> >> +	zone_sizes_init(min_low_pfn, max_low_pfn, max_pfn);
> >>  }
> >>  
> >>  /*
> >>
> > 
> > Any feedback on this patch?
> 
> Mike, Catalin, does this looks sensible to you? If so, should this be
> thrown into Russell's patch tracking system?

Makes perfect sense to me, so

Acked-by: Mike Rapoport <rppt@...ux.ibm.com>
 
> Thanks
> -- 
> Florian
> 

-- 
Sincerely yours,
Mike.