In preparation for FLEXIBLE_THP support, improve
folio_add_new_anon_rmap() to allow a non-pmd-mappable, large folio to be
passed to it. In this case, all contained pages are accounted using the
"small" pages scheme.
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
---
mm/rmap.c | 26 +++++++++++++++++++-------
1 file changed, 19 insertions(+), 7 deletions(-)
diff --git a/mm/rmap.c b/mm/rmap.c
index 1d8369549424..82ef5ba363d1 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1278,31 +1278,43 @@ void page_add_anon_rmap(struct page *page, struct vm_area_struct *vma,
* This means the inc-and-test can be bypassed.
* The folio does not have to be locked.
*
- * If the folio is large, it is accounted as a THP. As the folio
+ * If the folio is pmd-mappable, it is accounted as a THP. As the folio
* is new, it's assumed to be mapped exclusively by a single process.
*/
void folio_add_new_anon_rmap(struct folio *folio, struct vm_area_struct *vma,
unsigned long address)
{
- int nr;
+ int nr = folio_nr_pages(folio);
+ int i;
+ struct page *page;
- VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma);
+ VM_BUG_ON_VMA(address < vma->vm_start ||
+ address + (nr << PAGE_SHIFT) > vma->vm_end, vma);
__folio_set_swapbacked(folio);
- if (likely(!folio_test_pmd_mappable(folio))) {
+ if (!folio_test_large(folio)) {
/* increment count (starts at -1) */
atomic_set(&folio->_mapcount, 0);
- nr = 1;
+ __page_set_anon_rmap(folio, &folio->page, vma, address, 1);
+ } else if (!folio_test_pmd_mappable(folio)) {
+ /* increment count (starts at 0) */
+ atomic_set(&folio->_nr_pages_mapped, nr);
+
+ page = &folio->page;
+ for (i = 0; i < nr; i++, page++, address += PAGE_SIZE) {
+ /* increment count (starts at -1) */
+ atomic_set(&page->_mapcount, 0);
+ __page_set_anon_rmap(folio, page, vma, address, 1);
+ }
} else {
/* increment count (starts at -1) */
atomic_set(&folio->_entire_mapcount, 0);
atomic_set(&folio->_nr_pages_mapped, COMPOUND_MAPPED);
- nr = folio_nr_pages(folio);
__lruvec_stat_mod_folio(folio, NR_ANON_THPS, nr);
+ __page_set_anon_rmap(folio, &folio->page, vma, address, 1);
}
__lruvec_stat_mod_folio(folio, NR_ANON_MAPPED, nr);
- __page_set_anon_rmap(folio, &folio->page, vma, address, 1);
}
/**
--
2.25.1On Mon, Jul 3, 2023 at 7:53 AM Ryan Roberts <ryan.roberts@arm.com> wrote:
>
> In preparation for FLEXIBLE_THP support, improve
> folio_add_new_anon_rmap() to allow a non-pmd-mappable, large folio to be
> passed to it. In this case, all contained pages are accounted using the
> "small" pages scheme.
Nit: In this case, all *subpages* are accounted using the *order-0
folio* (or base page) scheme.
> Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Yu Zhao <yuzhao@google.com>
> mm/rmap.c | 26 +++++++++++++++++++-------
> 1 file changed, 19 insertions(+), 7 deletions(-)
>
> diff --git a/mm/rmap.c b/mm/rmap.c
> index 1d8369549424..82ef5ba363d1 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -1278,31 +1278,43 @@ void page_add_anon_rmap(struct page *page, struct vm_area_struct *vma,
> * This means the inc-and-test can be bypassed.
> * The folio does not have to be locked.
> *
> - * If the folio is large, it is accounted as a THP. As the folio
> + * If the folio is pmd-mappable, it is accounted as a THP. As the folio
> * is new, it's assumed to be mapped exclusively by a single process.
> */
> void folio_add_new_anon_rmap(struct folio *folio, struct vm_area_struct *vma,
> unsigned long address)
> {
> - int nr;
> + int nr = folio_nr_pages(folio);
> + int i;
> + struct page *page;
>
> - VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma);
> + VM_BUG_ON_VMA(address < vma->vm_start ||
> + address + (nr << PAGE_SHIFT) > vma->vm_end, vma);
> __folio_set_swapbacked(folio);
>
> - if (likely(!folio_test_pmd_mappable(folio))) {
> + if (!folio_test_large(folio)) {
> /* increment count (starts at -1) */
> atomic_set(&folio->_mapcount, 0);
> - nr = 1;
> + __page_set_anon_rmap(folio, &folio->page, vma, address, 1);
> + } else if (!folio_test_pmd_mappable(folio)) {
> + /* increment count (starts at 0) */
> + atomic_set(&folio->_nr_pages_mapped, nr);
> +
> + page = &folio->page;
> + for (i = 0; i < nr; i++, page++, address += PAGE_SIZE) {
> + /* increment count (starts at -1) */
> + atomic_set(&page->_mapcount, 0);
> + __page_set_anon_rmap(folio, page, vma, address, 1);
> + }
Nit: use folio_page(), e.g.,
} else if (!folio_test_pmd_mappable(folio)) {
int i;
for (i = 0; i < nr; i++) {
struct page *page = folio_page(folio, i);
/* increment count (starts at -1) */
atomic_set(&page->_mapcount, 0);
__page_set_anon_rmap(folio, page, vma, address + PAGE_SIZE * i, 1);
}
/* increment count (starts at 0) */
atomic_set(&folio->_nr_pages_mapped, nr);
} else {
> } else {
> /* increment count (starts at -1) */
> atomic_set(&folio->_entire_mapcount, 0);
> atomic_set(&folio->_nr_pages_mapped, COMPOUND_MAPPED);
> - nr = folio_nr_pages(folio);
> __lruvec_stat_mod_folio(folio, NR_ANON_THPS, nr);
> + __page_set_anon_rmap(folio, &folio->page, vma, address, 1);
> }
>
> __lruvec_stat_mod_folio(folio, NR_ANON_MAPPED, nr);
> - __page_set_anon_rmap(folio, &folio->page, vma, address, 1);
> }
On 7/4/2023 3:05 AM, Yu Zhao wrote:
> On Mon, Jul 3, 2023 at 7:53 AM Ryan Roberts <ryan.roberts@arm.com> wrote:
>>
>> In preparation for FLEXIBLE_THP support, improve
>> folio_add_new_anon_rmap() to allow a non-pmd-mappable, large folio to be
>> passed to it. In this case, all contained pages are accounted using the
>> "small" pages scheme.
>
> Nit: In this case, all *subpages* are accounted using the *order-0
> folio* (or base page) scheme.
Matthew suggested not to use subpage with folio. Using page with folio:
https://lore.kernel.org/linux-mm/Y9qiS%2FIxZOMx62t6@casper.infradead.org/
>
>> Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
>
> Reviewed-by: Yu Zhao <yuzhao@google.com>
>
>> mm/rmap.c | 26 +++++++++++++++++++-------
>> 1 file changed, 19 insertions(+), 7 deletions(-)
>>
>> diff --git a/mm/rmap.c b/mm/rmap.c
>> index 1d8369549424..82ef5ba363d1 100644
>> --- a/mm/rmap.c
>> +++ b/mm/rmap.c
>> @@ -1278,31 +1278,43 @@ void page_add_anon_rmap(struct page *page, struct vm_area_struct *vma,
>> * This means the inc-and-test can be bypassed.
>> * The folio does not have to be locked.
>> *
>> - * If the folio is large, it is accounted as a THP. As the folio
>> + * If the folio is pmd-mappable, it is accounted as a THP. As the folio
>> * is new, it's assumed to be mapped exclusively by a single process.
>> */
>> void folio_add_new_anon_rmap(struct folio *folio, struct vm_area_struct *vma,
>> unsigned long address)
>> {
>> - int nr;
>> + int nr = folio_nr_pages(folio);
>> + int i;
>> + struct page *page;
>>
>> - VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma);
>> + VM_BUG_ON_VMA(address < vma->vm_start ||
>> + address + (nr << PAGE_SHIFT) > vma->vm_end, vma);
>> __folio_set_swapbacked(folio);
>>
>> - if (likely(!folio_test_pmd_mappable(folio))) {
>> + if (!folio_test_large(folio)) {
>> /* increment count (starts at -1) */
>> atomic_set(&folio->_mapcount, 0);
>> - nr = 1;
>> + __page_set_anon_rmap(folio, &folio->page, vma, address, 1);
>> + } else if (!folio_test_pmd_mappable(folio)) {
>> + /* increment count (starts at 0) */
>> + atomic_set(&folio->_nr_pages_mapped, nr);
>> +
>> + page = &folio->page;
>> + for (i = 0; i < nr; i++, page++, address += PAGE_SIZE) {
>> + /* increment count (starts at -1) */
>> + atomic_set(&page->_mapcount, 0);
>> + __page_set_anon_rmap(folio, page, vma, address, 1);
>> + }
>
> Nit: use folio_page(), e.g.,
>
> } else if (!folio_test_pmd_mappable(folio)) {
> int i;
>
> for (i = 0; i < nr; i++) {
> struct page *page = folio_page(folio, i);
>
> /* increment count (starts at -1) */
> atomic_set(&page->_mapcount, 0);
> __page_set_anon_rmap(folio, page, vma, address + PAGE_SIZE * i, 1);
> }
> /* increment count (starts at 0) */
> atomic_set(&folio->_nr_pages_mapped, nr);
> } else {
>
>> } else {
>> /* increment count (starts at -1) */
>> atomic_set(&folio->_entire_mapcount, 0);
>> atomic_set(&folio->_nr_pages_mapped, COMPOUND_MAPPED);
>> - nr = folio_nr_pages(folio);
>> __lruvec_stat_mod_folio(folio, NR_ANON_THPS, nr);
>> + __page_set_anon_rmap(folio, &folio->page, vma, address, 1);
>> }
>>
>> __lruvec_stat_mod_folio(folio, NR_ANON_MAPPED, nr);
>> - __page_set_anon_rmap(folio, &folio->page, vma, address, 1);
>> }
On 04/07/2023 03:13, Yin, Fengwei wrote:
>
>
> On 7/4/2023 3:05 AM, Yu Zhao wrote:
>> On Mon, Jul 3, 2023 at 7:53 AM Ryan Roberts <ryan.roberts@arm.com> wrote:
>>>
>>> In preparation for FLEXIBLE_THP support, improve
>>> folio_add_new_anon_rmap() to allow a non-pmd-mappable, large folio to be
>>> passed to it. In this case, all contained pages are accounted using the
>>> "small" pages scheme.
>>
>> Nit: In this case, all *subpages* are accounted using the *order-0
>> folio* (or base page) scheme.
> Matthew suggested not to use subpage with folio. Using page with folio:
> https://lore.kernel.org/linux-mm/Y9qiS%2FIxZOMx62t6@casper.infradead.org/
OK, I'll change this to "In this case, all contained pages are accounted using
the *order-0 folio* (or base page) scheme."
>
>>
>>> Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
>>
>> Reviewed-by: Yu Zhao <yuzhao@google.com>
Thanks!
>>
>>> mm/rmap.c | 26 +++++++++++++++++++-------
>>> 1 file changed, 19 insertions(+), 7 deletions(-)
>>>
>>> diff --git a/mm/rmap.c b/mm/rmap.c
>>> index 1d8369549424..82ef5ba363d1 100644
>>> --- a/mm/rmap.c
>>> +++ b/mm/rmap.c
>>> @@ -1278,31 +1278,43 @@ void page_add_anon_rmap(struct page *page, struct vm_area_struct *vma,
>>> * This means the inc-and-test can be bypassed.
>>> * The folio does not have to be locked.
>>> *
>>> - * If the folio is large, it is accounted as a THP. As the folio
>>> + * If the folio is pmd-mappable, it is accounted as a THP. As the folio
>>> * is new, it's assumed to be mapped exclusively by a single process.
>>> */
>>> void folio_add_new_anon_rmap(struct folio *folio, struct vm_area_struct *vma,
>>> unsigned long address)
>>> {
>>> - int nr;
>>> + int nr = folio_nr_pages(folio);
>>> + int i;
>>> + struct page *page;
>>>
>>> - VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma);
>>> + VM_BUG_ON_VMA(address < vma->vm_start ||
>>> + address + (nr << PAGE_SHIFT) > vma->vm_end, vma);
>>> __folio_set_swapbacked(folio);
>>>
>>> - if (likely(!folio_test_pmd_mappable(folio))) {
>>> + if (!folio_test_large(folio)) {
>>> /* increment count (starts at -1) */
>>> atomic_set(&folio->_mapcount, 0);
>>> - nr = 1;
>>> + __page_set_anon_rmap(folio, &folio->page, vma, address, 1);
>>> + } else if (!folio_test_pmd_mappable(folio)) {
>>> + /* increment count (starts at 0) */
>>> + atomic_set(&folio->_nr_pages_mapped, nr);
>>> +
>>> + page = &folio->page;
>>> + for (i = 0; i < nr; i++, page++, address += PAGE_SIZE) {
>>> + /* increment count (starts at -1) */
>>> + atomic_set(&page->_mapcount, 0);
>>> + __page_set_anon_rmap(folio, page, vma, address, 1);
>>> + }
>>
>> Nit: use folio_page(), e.g.,
Yep, will change for v3.
>>
>> } else if (!folio_test_pmd_mappable(folio)) {
>> int i;
>>
>> for (i = 0; i < nr; i++) {
>> struct page *page = folio_page(folio, i);
>>
>> /* increment count (starts at -1) */
>> atomic_set(&page->_mapcount, 0);
>> __page_set_anon_rmap(folio, page, vma, address + PAGE_SIZE * i, 1);
>> }
>> /* increment count (starts at 0) */
>> atomic_set(&folio->_nr_pages_mapped, nr);
>> } else {
>>
>>> } else {
>>> /* increment count (starts at -1) */
>>> atomic_set(&folio->_entire_mapcount, 0);
>>> atomic_set(&folio->_nr_pages_mapped, COMPOUND_MAPPED);
>>> - nr = folio_nr_pages(folio);
>>> __lruvec_stat_mod_folio(folio, NR_ANON_THPS, nr);
>>> + __page_set_anon_rmap(folio, &folio->page, vma, address, 1);
>>> }
>>>
>>> __lruvec_stat_mod_folio(folio, NR_ANON_MAPPED, nr);
>>> - __page_set_anon_rmap(folio, &folio->page, vma, address, 1);
>>> }
On 7/3/2023 9:53 PM, Ryan Roberts wrote:
> In preparation for FLEXIBLE_THP support, improve
> folio_add_new_anon_rmap() to allow a non-pmd-mappable, large folio to be
> passed to it. In this case, all contained pages are accounted using the
> "small" pages scheme.
>
> Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Yin, Fengwei <fengwei.yin@intel.com>
> ---
> mm/rmap.c | 26 +++++++++++++++++++-------
> 1 file changed, 19 insertions(+), 7 deletions(-)
>
> diff --git a/mm/rmap.c b/mm/rmap.c
> index 1d8369549424..82ef5ba363d1 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -1278,31 +1278,43 @@ void page_add_anon_rmap(struct page *page, struct vm_area_struct *vma,
> * This means the inc-and-test can be bypassed.
> * The folio does not have to be locked.
> *
> - * If the folio is large, it is accounted as a THP. As the folio
> + * If the folio is pmd-mappable, it is accounted as a THP. As the folio
> * is new, it's assumed to be mapped exclusively by a single process.
> */
> void folio_add_new_anon_rmap(struct folio *folio, struct vm_area_struct *vma,
> unsigned long address)
> {
> - int nr;
> + int nr = folio_nr_pages(folio);
> + int i;
> + struct page *page;
>
> - VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma);
> + VM_BUG_ON_VMA(address < vma->vm_start ||
> + address + (nr << PAGE_SHIFT) > vma->vm_end, vma);
> __folio_set_swapbacked(folio);
>
> - if (likely(!folio_test_pmd_mappable(folio))) {
> + if (!folio_test_large(folio)) {
> /* increment count (starts at -1) */
> atomic_set(&folio->_mapcount, 0);
> - nr = 1;
> + __page_set_anon_rmap(folio, &folio->page, vma, address, 1);
> + } else if (!folio_test_pmd_mappable(folio)) {
> + /* increment count (starts at 0) */
> + atomic_set(&folio->_nr_pages_mapped, nr);
> +
> + page = &folio->page;
> + for (i = 0; i < nr; i++, page++, address += PAGE_SIZE) {
> + /* increment count (starts at -1) */
> + atomic_set(&page->_mapcount, 0);
> + __page_set_anon_rmap(folio, page, vma, address, 1);
> + }
> } else {
> /* increment count (starts at -1) */
> atomic_set(&folio->_entire_mapcount, 0);
> atomic_set(&folio->_nr_pages_mapped, COMPOUND_MAPPED);
> - nr = folio_nr_pages(folio);
> __lruvec_stat_mod_folio(folio, NR_ANON_THPS, nr);
> + __page_set_anon_rmap(folio, &folio->page, vma, address, 1);
> }
>
> __lruvec_stat_mod_folio(folio, NR_ANON_MAPPED, nr);
> - __page_set_anon_rmap(folio, &folio->page, vma, address, 1);
> }
>
> /**
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