[PATCHv2 5/7] x86/mm: set allowed range for memblock allocator

From: Pingfan Liu
Date: Fri Jan 11 2019 - 00:13:57 EST


Due to the incoming divergence of x86_32 and x86_64, there is requirement
to set the allowed allocating range at the early boot stage.
This patch also includes minor change to remove redundat cond check, refer
to memblock_find_in_range_node(), memblock_find_in_range() has already
protect itself from the case: start > end.

Signed-off-by: Pingfan Liu <kernelfans@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
Cc: Len Brown <lenb@xxxxxxxxxx>
Cc: Yinghai Lu <yinghai@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Chao Fan <fanc.fnst@xxxxxxxxxxxxxx>
Cc: Baoquan He <bhe@xxxxxxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: linux-acpi@xxxxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
---
arch/x86/mm/init.c | 24 +++++++++++++++++-------
1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index ef99f38..385b9cd 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -76,6 +76,14 @@ static unsigned long min_pfn_mapped;

static bool __initdata can_use_brk_pgt = true;

+static unsigned long min_pfn_allowed;
+static unsigned long max_pfn_allowed;
+void set_alloc_range(unsigned long low, unsigned long high)
+{
+ min_pfn_allowed = low;
+ max_pfn_allowed = high;
+}
+
/*
* Pages returned are already directly mapped.
*
@@ -100,12 +108,10 @@ __ref void *alloc_low_pages(unsigned int num)
if ((pgt_buf_end + num) > pgt_buf_top || !can_use_brk_pgt) {
unsigned long ret = 0;

- if (min_pfn_mapped < max_pfn_mapped) {
- ret = memblock_find_in_range(
- min_pfn_mapped << PAGE_SHIFT,
- max_pfn_mapped << PAGE_SHIFT,
- PAGE_SIZE * num , PAGE_SIZE);
- }
+ ret = memblock_find_in_range(
+ min_pfn_allowed << PAGE_SHIFT,
+ max_pfn_allowed << PAGE_SHIFT,
+ PAGE_SIZE * num, PAGE_SIZE);
if (ret)
memblock_reserve(ret, PAGE_SIZE * num);
else if (can_use_brk_pgt)
@@ -588,14 +594,17 @@ static void __init memory_map_top_down(unsigned long map_start,
start = map_start;
mapped_ram_size += init_range_memory_mapping(start,
last_start);
+ set_alloc_range(min_pfn_mapped, max_pfn_mapped);
last_start = start;
min_pfn_mapped = last_start >> PAGE_SHIFT;
if (mapped_ram_size >= step_size)
step_size = get_new_step_size(step_size);
}

- if (real_end < map_end)
+ if (real_end < map_end) {
init_range_memory_mapping(real_end, map_end);
+ set_alloc_range(min_pfn_mapped, max_pfn_mapped);
+ }
}

/**
@@ -636,6 +645,7 @@ static void __init memory_map_bottom_up(unsigned long map_start,
}

mapped_ram_size += init_range_memory_mapping(start, next);
+ set_alloc_range(min_pfn_mapped, max_pfn_mapped);
start = next;

if (mapped_ram_size >= step_size)
--
2.7.4