diff mbox series

[-next,v2,09/19] mm: mprotect: use a folio in change_pte_range()

Message ID 20231013085603.1227349-10-wangkefeng.wang@huawei.com
State New
Headers
Series mm: convert page cpupid functions to folios |

Commit Message

Kefeng Wang Oct. 13, 2023, 8:55 a.m. UTC 
  Use a folio in change_pte_range() to save three compound_head() calls.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 mm/mprotect.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

Comments

Matthew Wilcox Oct. 13, 2023, 3:13 p.m. UTC | #1 
On Fri, Oct 13, 2023 at 04:55:53PM +0800, Kefeng Wang wrote:
> Use a folio in change_pte_range() to save three compound_head() calls.

Yes, but here we have a change of behaviour, which should be argued
is desirable.  Before if a partial THP was mapped, or a fs large
folio, we would do this to individual pages.  Now we're doing it to the
entire folio.  Is that desirable?  I don't have the background to argue
either way.

> @@ -157,7 +159,7 @@ static long change_pte_range(struct mmu_gather *tlb,
>  					continue;
>  				if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING &&
>  				    !toptier)
> -					xchg_page_access_time(page,
> +					folio_xchg_access_time(folio,
>  						jiffies_to_msecs(jiffies));
>  			}
Kefeng Wang Oct. 14, 2023, 3:11 a.m. UTC | #2 
On 2023/10/13 23:13, Matthew Wilcox wrote:
> On Fri, Oct 13, 2023 at 04:55:53PM +0800, Kefeng Wang wrote:
>> Use a folio in change_pte_range() to save three compound_head() calls.
> 
> Yes, but here we have a change of behaviour, which should be argued
> is desirable.  Before if a partial THP was mapped, or a fs large
> folio, we would do this to individual pages.  Now we're doing it to the
> entire folio.  Is that desirable?  I don't have the background to argue
> either way.

The Huang's replay in v1[1] already mentioned this, we only use 
last_cpupid from head page, and large folio won't be handled from
do_numa_page(), and if large folio numa balancing is supported,
we could migrate the entire large folio mapped only one process,
or maybe split the large folio mapped multi-processes, and when
split it, we will copy the last_cpupid from head to the tail page.
Anyway, I think this change or the wp_page_reuse() won't break
current numa balancing.

Thanks.


[1]https://lore.kernel.org/linux-mm/874jixhfeu.fsf@yhuang6-desk2.ccr.corp.intel.com/
> 
>> @@ -157,7 +159,7 @@ static long change_pte_range(struct mmu_gather *tlb,
>>   					continue;
>>   				if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING &&
>>   				    !toptier)
>> -					xchg_page_access_time(page,
>> +					folio_xchg_access_time(folio,
>>   						jiffies_to_msecs(jiffies));
>>   			}
>
diff mbox series

Patch

diff --git a/mm/mprotect.c b/mm/mprotect.c
index f1dc8f8c84ef..81991102f785 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -114,7 +114,7 @@  static long change_pte_range(struct mmu_gather *tlb,
 			 * pages. See similar comment in change_huge_pmd.
 			 */
 			if (prot_numa) {
-				struct page *page;
+				struct folio *folio;
 				int nid;
 				bool toptier;
 
@@ -122,13 +122,14 @@  static long change_pte_range(struct mmu_gather *tlb,
 				if (pte_protnone(oldpte))
 					continue;
 
-				page = vm_normal_page(vma, addr, oldpte);
-				if (!page || is_zone_device_page(page) || PageKsm(page))
+				folio = vm_normal_folio(vma, addr, oldpte);
+				if (!folio || folio_is_zone_device(folio) ||
+				    folio_test_ksm(folio))
 					continue;
 
 				/* Also skip shared copy-on-write pages */
 				if (is_cow_mapping(vma->vm_flags) &&
-				    page_count(page) != 1)
+				    folio_ref_count(folio) != 1)
 					continue;
 
 				/*
@@ -136,14 +137,15 @@  static long change_pte_range(struct mmu_gather *tlb,
 				 * it cannot move them all from MIGRATE_ASYNC
 				 * context.
 				 */
-				if (page_is_file_lru(page) && PageDirty(page))
+				if (folio_is_file_lru(folio) &&
+				    folio_test_dirty(folio))
 					continue;
 
 				/*
 				 * Don't mess with PTEs if page is already on the node
 				 * a single-threaded process is running on.
 				 */
-				nid = page_to_nid(page);
+				nid = folio_nid(folio);
 				if (target_node == nid)
 					continue;
 				toptier = node_is_toptier(nid);
@@ -157,7 +159,7 @@  static long change_pte_range(struct mmu_gather *tlb,
 					continue;
 				if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING &&
 				    !toptier)
-					xchg_page_access_time(page,
+					folio_xchg_access_time(folio,
 						jiffies_to_msecs(jiffies));
 			}