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Subject[PATCH 2/5] x86: find_early_table_space based on memory ranges that are being mapped
Date
Current logic finds enough space for direct mapping page tables from 0
to end. Instead, we only need to find enough space to cover mr[0].start
to mr[nr_range].end -- the range that is actually being mapped by
init_memory_mapping()

This patch also reportedly fixes suspend/resume issue reported in:

https://lkml.org/lkml/2012/8/11/83

Signed-off-by: Jacob Shin <jacob.shin@amd.com>
---
arch/x86/mm/init.c | 62 +++++++++++++++++++++++++++++-----------------------
1 file changed, 35 insertions(+), 27 deletions(-)

diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 2f07e09..e2b21e0 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -35,40 +35,48 @@ struct map_range {
unsigned page_size_mask;
};

-static void __init find_early_table_space(struct map_range *mr, unsigned long end,
- int use_pse, int use_gbpages)
+/*
+ * First calculate space needed for kernel direct mapping page tables to cover
+ * mr[0].start to mr[nr_range - 1].end, while accounting for possible 2M and 1GB
+ * pages. Then find enough contiguous space for those page tables.
+ */
+static void __init find_early_table_space(struct map_range *mr, int nr_range)
{
- unsigned long puds, pmds, ptes, tables, start = 0, good_end = end;
+ int i;
+ unsigned long puds = 0, pmds = 0, ptes = 0, tables;
+ unsigned long start = 0, good_end;
phys_addr_t base;

- puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
- tables = roundup(puds * sizeof(pud_t), PAGE_SIZE);
-
- if (use_gbpages) {
- unsigned long extra;
-
- extra = end - ((end>>PUD_SHIFT) << PUD_SHIFT);
- pmds = (extra + PMD_SIZE - 1) >> PMD_SHIFT;
- } else
- pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
+ for (i = 0; i < nr_range; i++) {
+ unsigned long range, extra;

- tables += roundup(pmds * sizeof(pmd_t), PAGE_SIZE);
+ range = mr[i].end - mr[i].start;
+ puds += (range + PUD_SIZE - 1) >> PUD_SHIFT;

- if (use_pse) {
- unsigned long extra;
+ if (mr[i].page_size_mask & (1 << PG_LEVEL_1G)) {
+ extra = range - ((range >> PUD_SHIFT) << PUD_SHIFT);
+ pmds += (extra + PMD_SIZE - 1) >> PMD_SHIFT;
+ } else {
+ pmds += (range + PMD_SIZE - 1) >> PMD_SHIFT;
+ }

- extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT);
+ if (mr[i].page_size_mask & (1 << PG_LEVEL_2M)) {
+ extra = range - ((range >> PMD_SHIFT) << PMD_SHIFT);
#ifdef CONFIG_X86_32
- extra += PMD_SIZE;
+ extra += PMD_SIZE;
#endif
- /* The first 2/4M doesn't use large pages. */
- if (mr->start < PMD_SIZE)
- extra += mr->end - mr->start;
-
- ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
- } else
- ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ /* The first 2/4M doesn't use large pages. */
+ if (mr[i].start < PMD_SIZE)
+ extra += range;
+
+ ptes += (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ } else {
+ ptes += (range + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ }
+ }

+ tables = roundup(puds * sizeof(pud_t), PAGE_SIZE);
+ tables += roundup(pmds * sizeof(pmd_t), PAGE_SIZE);
tables += roundup(ptes * sizeof(pte_t), PAGE_SIZE);

#ifdef CONFIG_X86_32
@@ -86,7 +94,7 @@ static void __init find_early_table_space(struct map_range *mr, unsigned long en
pgt_buf_top = pgt_buf_start + (tables >> PAGE_SHIFT);

printk(KERN_DEBUG "kernel direct mapping tables up to %#lx @ [mem %#010lx-%#010lx]\n",
- end - 1, pgt_buf_start << PAGE_SHIFT,
+ mr[nr_range - 1].end - 1, pgt_buf_start << PAGE_SHIFT,
(pgt_buf_top << PAGE_SHIFT) - 1);
}

@@ -257,7 +265,7 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
* nodes are discovered.
*/
if (!after_bootmem)
- find_early_table_space(&mr[0], end, use_pse, use_gbpages);
+ find_early_table_space(mr, nr_range);

for (i = 0; i < nr_range; i++)
ret = kernel_physical_mapping_init(mr[i].start, mr[i].end,
--
1.7.9.5



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