diff options
| author |   Will Deacon <will@kernel.org> | 2020-05-26 18:33:02 +0100 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2020-06-02 18:45:51 -0700 |
| commit | 1996d47a0db27a3071f1a6587123185ba98c4585 (patch) | |
| tree | 3b849e4c43873e8fc1fead51e5531bcb2d0d2b19 /arch/sparc | |
| parent | sparc32: mm: Disable SPLIT_PTLOCK_CPUS (diff) | |
| download | linux-dev-1996d47a0db27a3071f1a6587123185ba98c4585.tar.xz linux-dev-1996d47a0db27a3071f1a6587123185ba98c4585.zip | |
sparc32: mm: Only call ctor()/dtor() functions for first and last user
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>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch/sparc')
| -rw-r--r-- | arch/sparc/mm/srmmu.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/arch/sparc/mm/srmmu.c b/arch/sparc/mm/srmmu.c index 589370a21b12..116d19a390f2 100644 --- a/arch/sparc/mm/srmmu.c +++ b/arch/sparc/mm/srmmu.c @@ -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); } |