On Thu, Apr 23, 2020 at 10:57:20AM +0800, Baoquan He wrote:
> On 04/23/20 at 10:53am, Baoquan He wrote:
> > On 04/12/20 at 10:48pm, Mike Rapoport wrote:
> > > From: Mike Rapoport <r...@linux.ibm.com>
> > >
> > > Some architectures (e.g. ARC) have the ZONE_HIGHMEM zone below the
> > > ZONE_NORMAL. Allowing free_area_init() parse max_zone_pfn array even it is
> > > sorted in descending order allows using free_area_init() on such
> > > architectures.
> > >
> > > Add top -> down traversal of max_zone_pfn array in free_area_init() and
> > > use
> > > the latter in ARC node/zone initialization.
> >
> > Or maybe leave ARC as is. The change in this patchset doesn't impact
> > ARC's handling about zone initialization, leaving it as is can reduce
> > the complication in implementation of free_area_init(), which is a
> > common function. So I personally don't see a strong motivation to have
> > this patch.
>
> OK, seems this patch is prepared to simplify free_area_init_node(), so
> take back what I said at above.
>
> Then this looks necessary, even though it introduces special case into
> common function free_area_init().
The idea is to have a single free_area_init() for all architectures
without keeping two completely different ways of calculating the zone
extents.
Another thing, is that with this we could eventually switch ARC from
DISCONTIGMEM.
> Reviewed-by: Baoquan He <b...@redhat.com>
>
> >
> > >
> > > Signed-off-by: Mike Rapoport <r...@linux.ibm.com>
> > > ---
> > > arch/arc/mm/init.c | 36 +++++++-----------------------------
> > > mm/page_alloc.c | 24 +++++++++++++++++++-----
> > > 2 files changed, 26 insertions(+), 34 deletions(-)
> > >
> > > diff --git a/arch/arc/mm/init.c b/arch/arc/mm/init.c
> > > index 0920c969c466..41eb9be1653c 100644
> > > --- a/arch/arc/mm/init.c
> > > +++ b/arch/arc/mm/init.c
> > > @@ -63,11 +63,13 @@ void __init early_init_dt_add_memory_arch(u64 base,
> > > u64 size)
> > >
> > > low_mem_sz = size;
> > > in_use = 1;
> > > + memblock_add_node(base, size, 0);
> > > } else {
> > > #ifdef CONFIG_HIGHMEM
> > > high_mem_start = base;
> > > high_mem_sz = size;
> > > in_use = 1;
> > > + memblock_add_node(base, size, 1);
> > > #endif
> > > }
> > >
> > > @@ -83,8 +85,7 @@ void __init early_init_dt_add_memory_arch(u64 base, u64
> > > size)
> > > */
> > > void __init setup_arch_memory(void)
> > > {
> > > - unsigned long zones_size[MAX_NR_ZONES];
> > > - unsigned long zones_holes[MAX_NR_ZONES];
> > > + unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
> > >
> > > init_mm.start_code = (unsigned long)_text;
> > > init_mm.end_code = (unsigned long)_etext;
> > > @@ -115,7 +116,6 @@ void __init setup_arch_memory(void)
> > > * the crash
> > > */
> > >
> > > - memblock_add_node(low_mem_start, low_mem_sz, 0);
> > > memblock_reserve(CONFIG_LINUX_LINK_BASE,
> > > __pa(_end) - CONFIG_LINUX_LINK_BASE);
> > >
> > > @@ -133,22 +133,7 @@ void __init setup_arch_memory(void)
> > > memblock_dump_all();
> > >
> > > /*----------------- node/zones setup --------------------------*/
> > > - memset(zones_size, 0, sizeof(zones_size));
> > > - memset(zones_holes, 0, sizeof(zones_holes));
> > > -
> > > - zones_size[ZONE_NORMAL] = max_low_pfn - min_low_pfn;
> > > - zones_holes[ZONE_NORMAL] = 0;
> > > -
> > > - /*
> > > - * We can't use the helper free_area_init(zones[]) because it uses
> > > - * PAGE_OFFSET to compute the @min_low_pfn which would be wrong
> > > - * when our kernel doesn't start at PAGE_OFFSET, i.e.
> > > - * PAGE_OFFSET != CONFIG_LINUX_RAM_BASE
> > > - */
> > > - free_area_init_node(0, /* node-id */
> > > - zones_size, /* num pages per zone */
> > > - min_low_pfn, /* first pfn of node */
> > > - zones_holes); /* holes */
> > > + max_zone_pfn[ZONE_NORMAL] = max_low_pfn;
> > >
> > > #ifdef CONFIG_HIGHMEM
> > > /*
> > > @@ -168,20 +153,13 @@ void __init setup_arch_memory(void)
> > > min_high_pfn = PFN_DOWN(high_mem_start);
> > > max_high_pfn = PFN_DOWN(high_mem_start + high_mem_sz);
> > >
> > > - zones_size[ZONE_NORMAL] = 0;
> > > - zones_holes[ZONE_NORMAL] = 0;
> > > -
> > > - zones_size[ZONE_HIGHMEM] = max_high_pfn - min_high_pfn;
> > > - zones_holes[ZONE_HIGHMEM] = 0;
> > > -
> > > - free_area_init_node(1, /* node-id */
> > > - zones_size, /* num pages per zone */
> > > - min_high_pfn, /* first pfn of node */
> > > - zones_holes); /* holes */
> > > + max_zone_pfn[ZONE_HIGHMEM] = max_high_pfn;
> > >
> > > high_memory = (void *)(min_high_pfn << PAGE_SHIFT);
> > > kmap_init();
> > > #endif
> > > +
> > > + free_area_init(max_zone_pfn);
> > > }
> > >
> > > /*
> > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> > > index 343d87b8697d..376434c7a78b 100644
> > > --- a/mm/page_alloc.c
> > > +++ b/mm/page_alloc.c
> > > @@ -7429,7 +7429,8 @@ static void check_for_memory(pg_data_t *pgdat, int
> > > nid)
> > > void __init free_area_init(unsigned long *max_zone_pfn)
> > > {
> > > unsigned long start_pfn, end_pfn;
> > > - int i, nid;
> > > + int i, nid, zone;
> > > + bool descending = false;
> > >
> > > /* Record where the zone boundaries are */
> > > memset(arch_zone_lowest_possible_pfn, 0,
> > > @@ -7439,13 +7440,26 @@ void __init free_area_init(unsigned long
> > > *max_zone_pfn)
> > >
> > > start_pfn = find_min_pfn_with_active_regions();
> > >
> > > + /*
> > > + * Some architecturs, e.g. ARC may have ZONE_HIGHMEM below
> > > + * ZONE_NORMAL. For such cases we allow max_zone_pfn sorted in the
> > > + * descending order
> > > + */
> > > + if (MAX_NR_ZONES > 1 && max_zone_pfn[0] > max_zone_pfn[1])
> > > + descending = true;
> > > +
> > > for (i = 0; i < MAX_NR_ZONES; i++) {
> > > - if (i == ZONE_MOVABLE)
> > > + if (descending)
> > > + zone = MAX_NR_ZONES - i - 1;
> > > + else
> > > + zone = i;
> > > +
> > > + if (zone == ZONE_MOVABLE)
> > > continue;
> > >
> > > - end_pfn = max(max_zone_pfn[i], start_pfn);
> > > - arch_zone_lowest_possible_pfn[i] = start_pfn;
> > > - arch_zone_highest_possible_pfn[i] = end_pfn;
> > > + end_pfn = max(max_zone_pfn[zone], start_pfn);
> > > + arch_zone_lowest_possible_pfn[zone] = start_pfn;
> > > + arch_zone_highest_possible_pfn[zone] = end_pfn;
> > >
> > > start_pfn = end_pfn;
> > > }
> > > --
> > > 2.25.1
> > >
>
--
Sincerely yours,
Mike.
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