@@ -364,9 +364,13 @@ pgtable_t pte_alloc_one(struct mm_struct *mm)
if ((ptep = pte_alloc_one_kernel(mm)) == 0)
return NULL;
page = pfn_to_page(__nocache_pa((unsigned long)ptep) >> PAGE_SHIFT);
- if (!pgtable_pte_page_ctor(page)) {
- return NULL;
+ spin_lock(&mm->page_table_lock);
+ if (page_ref_inc_return(page) == 2 && !pgtable_pte_page_ctor(page)) {
+ page_ref_dec(page);
+ ptep = NULL;
}
+ spin_unlock(&mm->page_table_lock);
+
return ptep;
}
@@ -375,7 +379,11 @@ void pte_free(struct mm_struct *mm, pgtable_t ptep)
struct page *page;
page = pfn_to_page(__nocache_pa((unsigned long)ptep) >> PAGE_SHIFT);
- pgtable_pte_page_dtor(page);
+ spin_lock(&mm->page_table_lock);
+ if (page_ref_dec_return(page) == 1)
+ pgtable_pte_page_dtor(page);
+ spin_unlock(&mm->page_table_lock);
+
srmmu_free_nocache(ptep, SRMMU_PTE_TABLE_SIZE);
}
The SRMMU page-table allocator allocates multiple PTE tables per page, since they are only 1K in size. However, this means that calls to pgtable_pte_page_{ctor,dtor}() must be serialised and performed only by the first and last page-table allocation for the page respectively. Use the page reference count to track how many PTE tables we have allocated for a given page returned by the SRMMU allocator and only call the ctor()/dtor() functions for the first and last user respectively. Cc: David S. Miller <davem@davemloft.net> Fixes: 8c8f3156dd40 ("sparc32: mm: Reduce allocation size for PMD and PTE tables") Signed-off-by: Will Deacon <will@kernel.org> --- arch/sparc/mm/srmmu.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-)