Re: [PATCH] mm: memblock: add more debug logs

[Faiyaz Mohammed]

On 11/10/2020 11:46 PM, Mike Rapoport wrote:
> Hi,
>
> On Tue, Nov 10, 2020 at 05:49:58PM +0530, Faiyaz Mohammed wrote:
> > Exact caller of memblock_phys_alloc_range is not available with
> > "memblock=debug". Below information is not enough for memory accounting.
> > for example:
> > [    0.000000] memblock_reserve: [0x000000023fc6b000-0x000000023fc6bfff] memblock_alloc_range_nid+0xc0/0x188
> >
> > To enhance the memblock_dbg information or to get the exact owner of the
> > memblock_reserve, add debug logs in memblock_phys_alloc_range function.
> Why would you want to use memblock=debug for memory accounting or for
> tracking of the owners of the reserved memory?
We do memblock reserved accounting to track owners to know size of memory

allocated by different drivers/owners through memblock_reserve, which help

in comparing different kernel version and in optimizations.

> > After adding logs:
> > [    0.000000] memblock_phys_alloc_range: 4096 bytes align=0x1000 from=0x0000000000000000 max_addr=0x0000000000000000 early_pgtable_alloc+0x24/0x178
> > [    0.000000] memblock_reserve: [0x000000023fc6b000-0x000000023fc6bfff] memblock_alloc_range_nid+0xc0/0x188
> >
> > Signed-off-by: Faiyaz Mohammed <faiyazm@xxxxxxxxxxxxxx>
> > ---
> >   mm/memblock.c | 3 +++
> >   1 file changed, 3 insertions(+)
> >
> > diff --git a/mm/memblock.c b/mm/memblock.c
> > index 049df41..f65af9f 100644
> > --- a/mm/memblock.c
> > +++ b/mm/memblock.c
> > @@ -1419,6 +1419,9 @@ phys_addr_t __init memblock_phys_alloc_range(phys_addr_t size,
> >   					     phys_addr_t start,
> >   					     phys_addr_t end)
> >   {
> > +	memblock_dbg("%s: %llu bytes align=0x%llx from=%pa max_addr=%pa %pS\n",
> > +			__func__, (u64)size, (u64)align, &start, &end,
> > +			(void *)_RET_IP_);
> >   	return memblock_alloc_range_nid(size, align, start, end, NUMA_NO_NODE,
> >   					false);
> >   }
> > --
> > QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a
> > member of the Code Aurora Forum, hosted by The Linux Foundation