diff mbox series

[-v4,4/9] migrate_pages: split unmap_and_move() to _unmap() and _move()

Message ID 20230206063313.635011-5-ying.huang@intel.com (mailing list archive)
State New
Headers show
Series migrate_pages(): batch TLB flushing | expand

Commit Message

Huang, Ying Feb. 6, 2023, 6:33 a.m. UTC
This is a preparation patch to batch the folio unmapping and moving.

In this patch, unmap_and_move() is split to migrate_folio_unmap() and
migrate_folio_move().  So, we can batch _unmap() and _move() in
different loops later.  To pass some information between unmap and
move, the original unused dst->mapping and dst->private are used.

Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Bharata B Rao <bharata@amd.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: haoxin <xhao@linux.alibaba.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
---
 include/linux/migrate.h |   1 +
 mm/migrate.c            | 170 ++++++++++++++++++++++++++++++----------
 2 files changed, 130 insertions(+), 41 deletions(-)

Comments

haoxin Feb. 7, 2023, 5:11 p.m. UTC | #1
在 2023/2/6 下午2:33, Huang Ying 写道:
> This is a preparation patch to batch the folio unmapping and moving.
>
> In this patch, unmap_and_move() is split to migrate_folio_unmap() and
> migrate_folio_move().  So, we can batch _unmap() and _move() in
> different loops later.  To pass some information between unmap and
> move, the original unused dst->mapping and dst->private are used.
>
> Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
> Cc: Zi Yan <ziy@nvidia.com>
> Cc: Yang Shi <shy828301@gmail.com>
> Cc: Oscar Salvador <osalvador@suse.de>
> Cc: Matthew Wilcox <willy@infradead.org>
> Cc: Bharata B Rao <bharata@amd.com>
> Cc: Alistair Popple <apopple@nvidia.com>
> Cc: haoxin <xhao@linux.alibaba.com>
> Cc: Minchan Kim <minchan@kernel.org>
> Cc: Mike Kravetz <mike.kravetz@oracle.com>
> Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> ---
>   include/linux/migrate.h |   1 +
>   mm/migrate.c            | 170 ++++++++++++++++++++++++++++++----------
>   2 files changed, 130 insertions(+), 41 deletions(-)
>
> diff --git a/include/linux/migrate.h b/include/linux/migrate.h
> index 3ef77f52a4f0..7376074f2e1e 100644
> --- a/include/linux/migrate.h
> +++ b/include/linux/migrate.h
> @@ -18,6 +18,7 @@ struct migration_target_control;
>    * - zero on page migration success;
>    */
>   #define MIGRATEPAGE_SUCCESS		0
> +#define MIGRATEPAGE_UNMAP		1
>   
>   /**
>    * struct movable_operations - Driver page migration
> diff --git a/mm/migrate.c b/mm/migrate.c
> index 9a667039c34c..0428449149f4 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -1009,11 +1009,53 @@ static int move_to_new_folio(struct folio *dst, struct folio *src,
>   	return rc;
>   }
>   
> -static int __unmap_and_move(struct folio *src, struct folio *dst,
> +/*
> + * To record some information during migration, we uses
uses / use
>   some unused
> + * fields (mapping and private) of struct folio of the newly allocated
> + * destination folio.  This is safe because nobody is using them
> + * except us.
> + */
> +static void __migrate_folio_record(struct folio *dst,
> +				   unsigned long page_was_mapped,
> +				   struct anon_vma *anon_vma)
> +{
> +	dst->mapping = (void *)anon_vma;
> +	dst->private = (void *)page_was_mapped;
> +}
> +
> +static void __migrate_folio_extract(struct folio *dst,
> +				   int *page_was_mappedp,
> +				   struct anon_vma **anon_vmap)
> +{
> +	*anon_vmap = (void *)dst->mapping;
> +	*page_was_mappedp = (unsigned long)dst->private;
> +	dst->mapping = NULL;
> +	dst->private = NULL;
> +}
> +
> +/* Cleanup src folio upon migration success */
> +static void migrate_folio_done(struct folio *src,
> +			       enum migrate_reason reason)
> +{
> +	/*
> +	 * Compaction can migrate also non-LRU pages which are
> +	 * not accounted to NR_ISOLATED_*. They can be recognized
> +	 * as __PageMovable
> +	 */
> +	if (likely(!__folio_test_movable(src)))
> +		mod_node_page_state(folio_pgdat(src), NR_ISOLATED_ANON +
> +				    folio_is_file_lru(src), -folio_nr_pages(src));
> +
> +	if (reason != MR_MEMORY_FAILURE)
> +		/* We release the page in page_handle_poison. */
> +		folio_put(src);
> +}
> +
> +static int __migrate_folio_unmap(struct folio *src, struct folio *dst,
>   				int force, enum migrate_mode mode)
>   {
>   	int rc = -EAGAIN;
> -	bool page_was_mapped = false;
> +	int page_was_mapped = 0;
>   	struct anon_vma *anon_vma = NULL;
>   	bool is_lru = !__PageMovable(&src->page);
>   
> @@ -1089,8 +1131,8 @@ static int __unmap_and_move(struct folio *src, struct folio *dst,
>   		goto out_unlock;
>   
>   	if (unlikely(!is_lru)) {
> -		rc = move_to_new_folio(dst, src, mode);
> -		goto out_unlock_both;
> +		__migrate_folio_record(dst, page_was_mapped, anon_vma);
> +		return MIGRATEPAGE_UNMAP;
>   	}
>   
>   	/*
> @@ -1115,11 +1157,42 @@ static int __unmap_and_move(struct folio *src, struct folio *dst,
>   		VM_BUG_ON_FOLIO(folio_test_anon(src) &&
>   			       !folio_test_ksm(src) && !anon_vma, src);
>   		try_to_migrate(src, 0);
> -		page_was_mapped = true;
> +		page_was_mapped = 1;
>   	}
>   
> -	if (!folio_mapped(src))
> -		rc = move_to_new_folio(dst, src, mode);
> +	if (!folio_mapped(src)) {
> +		__migrate_folio_record(dst, page_was_mapped, anon_vma);
> +		return MIGRATEPAGE_UNMAP;
> +	}
> +
> +	if (page_was_mapped)
> +		remove_migration_ptes(src, src, false);
> +
> +out_unlock_both:
> +	folio_unlock(dst);
> +out_unlock:
> +	/* Drop an anon_vma reference if we took one */
> +	if (anon_vma)
> +		put_anon_vma(anon_vma);
> +	folio_unlock(src);
> +out:
> +
> +	return rc;
> +}
> +
> +static int __migrate_folio_move(struct folio *src, struct folio *dst,
> +				enum migrate_mode mode)
> +{
> +	int rc;
> +	int page_was_mapped = 0;
> +	struct anon_vma *anon_vma = NULL;
> +	bool is_lru = !__PageMovable(&src->page);
> +
> +	__migrate_folio_extract(dst, &page_was_mapped, &anon_vma);
> +
> +	rc = move_to_new_folio(dst, src, mode);
> +	if (unlikely(!is_lru))
> +		goto out_unlock_both;
>   
>   	/*
>   	 * When successful, push dst to LRU immediately: so that if it
> @@ -1142,12 +1215,10 @@ static int __unmap_and_move(struct folio *src, struct folio *dst,
>   
>   out_unlock_both:
>   	folio_unlock(dst);
> -out_unlock:
>   	/* Drop an anon_vma reference if we took one */
>   	if (anon_vma)
>   		put_anon_vma(anon_vma);
>   	folio_unlock(src);
> -out:
>   	/*
>   	 * If migration is successful, decrease refcount of dst,
>   	 * which will not free the page because new page owner increased
> @@ -1159,19 +1230,15 @@ static int __unmap_and_move(struct folio *src, struct folio *dst,
>   	return rc;
>   }
>   
> -/*
> - * Obtain the lock on folio, remove all ptes and migrate the folio
> - * to the newly allocated folio in dst.
> - */
> -static int unmap_and_move(new_page_t get_new_page,
> -				   free_page_t put_new_page,
> -				   unsigned long private, struct folio *src,
> -				   int force, enum migrate_mode mode,
> -				   enum migrate_reason reason,
> -				   struct list_head *ret)
> +/* Obtain the lock on page, remove all ptes. */
> +static int migrate_folio_unmap(new_page_t get_new_page, free_page_t put_new_page,
> +			       unsigned long private, struct folio *src,
> +			       struct folio **dstp, int force,
> +			       enum migrate_mode mode, enum migrate_reason reason,
> +			       struct list_head *ret)
>   {
>   	struct folio *dst;
> -	int rc = MIGRATEPAGE_SUCCESS;
> +	int rc = MIGRATEPAGE_UNMAP;
>   	struct page *newpage = NULL;
>   
>   	if (!thp_migration_supported() && folio_test_transhuge(src))
> @@ -1182,20 +1249,50 @@ static int unmap_and_move(new_page_t get_new_page,
>   		folio_clear_active(src);
>   		folio_clear_unevictable(src);
>   		/* free_pages_prepare() will clear PG_isolated. */
> -		goto out;
> +		list_del(&src->lru);
> +		migrate_folio_done(src, reason);
> +		return MIGRATEPAGE_SUCCESS;
>   	}
>   
>   	newpage = get_new_page(&src->page, private);
>   	if (!newpage)
>   		return -ENOMEM;
>   	dst = page_folio(newpage);
> +	*dstp = dst;
>   
>   	dst->private = NULL;
> -	rc = __unmap_and_move(src, dst, force, mode);
> +	rc = __migrate_folio_unmap(src, dst, force, mode);
> +	if (rc == MIGRATEPAGE_UNMAP)
> +		return rc;
> +
> +	/*
> +	 * A page that has not been migrated will have kept its
> +	 * references and be restored.
> +	 */
> +	/* restore the folio to right list. */
> +	if (rc != -EAGAIN)
> +		list_move_tail(&src->lru, ret);
> +
> +	if (put_new_page)
> +		put_new_page(&dst->page, private);
> +	else
> +		folio_put(dst);
> +
> +	return rc;
> +}
> +
> +/* Migrate the folio to the newly allocated folio in dst. */
> +static int migrate_folio_move(free_page_t put_new_page, unsigned long private,
> +			      struct folio *src, struct folio *dst,
> +			      enum migrate_mode mode, enum migrate_reason reason,
> +			      struct list_head *ret)
> +{
> +	int rc;
> +
> +	rc = __migrate_folio_move(src, dst, mode);
>   	if (rc == MIGRATEPAGE_SUCCESS)
>   		set_page_owner_migrate_reason(&dst->page, reason);
>   
> -out:
>   	if (rc != -EAGAIN) {
>   		/*
>   		 * A folio that has been migrated has all references
> @@ -1211,20 +1308,7 @@ static int unmap_and_move(new_page_t get_new_page,
>   	 * we want to retry.
>   	 */
>   	if (rc == MIGRATEPAGE_SUCCESS) {
> -		/*
> -		 * Compaction can migrate also non-LRU folios which are
> -		 * not accounted to NR_ISOLATED_*. They can be recognized
> -		 * as __folio_test_movable
> -		 */
> -		if (likely(!__folio_test_movable(src)))
> -			mod_node_page_state(folio_pgdat(src), NR_ISOLATED_ANON +
> -					folio_is_file_lru(src), -folio_nr_pages(src));
> -
> -		if (reason != MR_MEMORY_FAILURE)
> -			/*
> -			 * We release the folio in page_handle_poison.
> -			 */
> -			folio_put(src);
> +		migrate_folio_done(src, reason);
>   	} else {
>   		if (rc != -EAGAIN)
>   			list_add_tail(&src->lru, ret);
> @@ -1516,7 +1600,7 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page,
>   	int pass = 0;
>   	bool is_large = false;
>   	bool is_thp = false;
> -	struct folio *folio, *folio2;
> +	struct folio *folio, *folio2, *dst = NULL;
>   	int rc, nr_pages;
>   	LIST_HEAD(split_folios);
>   	bool nosplit = (reason == MR_NUMA_MISPLACED);
> @@ -1543,9 +1627,13 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page,
>   
>   			cond_resched();
>   
> -			rc = unmap_and_move(get_new_page, put_new_page,
> -					    private, folio, pass > 2, mode,
> -					    reason, ret_folios);
> +			rc = migrate_folio_unmap(get_new_page, put_new_page, private,
> +						 folio, &dst, pass > 2, mode,
> +						 reason, ret_folios);
> +			if (rc == MIGRATEPAGE_UNMAP)
> +				rc = migrate_folio_move(put_new_page, private,
> +							folio, dst, mode,
> +							reason, ret_folios);
How to deal with the whole  pages are ummaped success,  but only part  
pages are moved success ?
>   			/*
>   			 * The rules are:
>   			 *	Success: folio will be freed
haoxin Feb. 7, 2023, 5:27 p.m. UTC | #2
在 2023/2/8 上午1:11, haoxin 写道:
>
> 在 2023/2/6 下午2:33, Huang Ying 写道:
>> This is a preparation patch to batch the folio unmapping and moving.
>>
>> In this patch, unmap_and_move() is split to migrate_folio_unmap() and
>> migrate_folio_move().  So, we can batch _unmap() and _move() in
>> different loops later.  To pass some information between unmap and
>> move, the original unused dst->mapping and dst->private are used.
>>
>> Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
>> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
>> Cc: Zi Yan <ziy@nvidia.com>
>> Cc: Yang Shi <shy828301@gmail.com>
>> Cc: Oscar Salvador <osalvador@suse.de>
>> Cc: Matthew Wilcox <willy@infradead.org>
>> Cc: Bharata B Rao <bharata@amd.com>
>> Cc: Alistair Popple <apopple@nvidia.com>
>> Cc: haoxin <xhao@linux.alibaba.com>
>> Cc: Minchan Kim <minchan@kernel.org>
>> Cc: Mike Kravetz <mike.kravetz@oracle.com>
>> Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
>> ---
>>   include/linux/migrate.h |   1 +
>>   mm/migrate.c            | 170 ++++++++++++++++++++++++++++++----------
>>   2 files changed, 130 insertions(+), 41 deletions(-)
>>
>> diff --git a/include/linux/migrate.h b/include/linux/migrate.h
>> index 3ef77f52a4f0..7376074f2e1e 100644
>> --- a/include/linux/migrate.h
>> +++ b/include/linux/migrate.h
>> @@ -18,6 +18,7 @@ struct migration_target_control;
>>    * - zero on page migration success;
>>    */
>>   #define MIGRATEPAGE_SUCCESS        0
>> +#define MIGRATEPAGE_UNMAP        1
>>     /**
>>    * struct movable_operations - Driver page migration
>> diff --git a/mm/migrate.c b/mm/migrate.c
>> index 9a667039c34c..0428449149f4 100644
>> --- a/mm/migrate.c
>> +++ b/mm/migrate.c
>> @@ -1009,11 +1009,53 @@ static int move_to_new_folio(struct folio 
>> *dst, struct folio *src,
>>       return rc;
>>   }
>>   -static int __unmap_and_move(struct folio *src, struct folio *dst,
>> +/*
>> + * To record some information during migration, we uses
> uses / use
>>   some unused
>> + * fields (mapping and private) of struct folio of the newly allocated
>> + * destination folio.  This is safe because nobody is using them
>> + * except us.
>> + */
>> +static void __migrate_folio_record(struct folio *dst,
>> +                   unsigned long page_was_mapped,
>> +                   struct anon_vma *anon_vma)
>> +{
>> +    dst->mapping = (void *)anon_vma;
>> +    dst->private = (void *)page_was_mapped;
>> +}
>> +
>> +static void __migrate_folio_extract(struct folio *dst,
>> +                   int *page_was_mappedp,
>> +                   struct anon_vma **anon_vmap)
>> +{
>> +    *anon_vmap = (void *)dst->mapping;
>> +    *page_was_mappedp = (unsigned long)dst->private;
>> +    dst->mapping = NULL;
>> +    dst->private = NULL;
>> +}
>> +
>> +/* Cleanup src folio upon migration success */
>> +static void migrate_folio_done(struct folio *src,
>> +                   enum migrate_reason reason)
>> +{
>> +    /*
>> +     * Compaction can migrate also non-LRU pages which are
>> +     * not accounted to NR_ISOLATED_*. They can be recognized
>> +     * as __PageMovable
>> +     */
>> +    if (likely(!__folio_test_movable(src)))
>> +        mod_node_page_state(folio_pgdat(src), NR_ISOLATED_ANON +
>> +                    folio_is_file_lru(src), -folio_nr_pages(src));
>> +
>> +    if (reason != MR_MEMORY_FAILURE)
>> +        /* We release the page in page_handle_poison. */
>> +        folio_put(src);
>> +}
>> +
>> +static int __migrate_folio_unmap(struct folio *src, struct folio *dst,
>>                   int force, enum migrate_mode mode)
>>   {
>>       int rc = -EAGAIN;
>> -    bool page_was_mapped = false;
>> +    int page_was_mapped = 0;
>>       struct anon_vma *anon_vma = NULL;
>>       bool is_lru = !__PageMovable(&src->page);
>>   @@ -1089,8 +1131,8 @@ static int __unmap_and_move(struct folio 
>> *src, struct folio *dst,
>>           goto out_unlock;
>>         if (unlikely(!is_lru)) {
>> -        rc = move_to_new_folio(dst, src, mode);
>> -        goto out_unlock_both;
>> +        __migrate_folio_record(dst, page_was_mapped, anon_vma);
>> +        return MIGRATEPAGE_UNMAP;
>>       }
>>         /*
>> @@ -1115,11 +1157,42 @@ static int __unmap_and_move(struct folio 
>> *src, struct folio *dst,
>>           VM_BUG_ON_FOLIO(folio_test_anon(src) &&
>>                      !folio_test_ksm(src) && !anon_vma, src);
>>           try_to_migrate(src, 0);
>> -        page_was_mapped = true;
>> +        page_was_mapped = 1;
>>       }
>>   -    if (!folio_mapped(src))
>> -        rc = move_to_new_folio(dst, src, mode);
>> +    if (!folio_mapped(src)) {
>> +        __migrate_folio_record(dst, page_was_mapped, anon_vma);
>> +        return MIGRATEPAGE_UNMAP;
>> +    }
>> +
>> +    if (page_was_mapped)
>> +        remove_migration_ptes(src, src, false);
>> +
>> +out_unlock_both:
>> +    folio_unlock(dst);
>> +out_unlock:
>> +    /* Drop an anon_vma reference if we took one */
>> +    if (anon_vma)
>> +        put_anon_vma(anon_vma);
>> +    folio_unlock(src);
>> +out:
>> +
>> +    return rc;
>> +}
>> +
>> +static int __migrate_folio_move(struct folio *src, struct folio *dst,
>> +                enum migrate_mode mode)
>> +{
>> +    int rc;
>> +    int page_was_mapped = 0;
>> +    struct anon_vma *anon_vma = NULL;
>> +    bool is_lru = !__PageMovable(&src->page);
>> +
>> +    __migrate_folio_extract(dst, &page_was_mapped, &anon_vma);
>> +
>> +    rc = move_to_new_folio(dst, src, mode);
>> +    if (unlikely(!is_lru))
>> +        goto out_unlock_both;
>>         /*
>>        * When successful, push dst to LRU immediately: so that if it
>> @@ -1142,12 +1215,10 @@ static int __unmap_and_move(struct folio 
>> *src, struct folio *dst,
>>     out_unlock_both:
>>       folio_unlock(dst);
>> -out_unlock:
>>       /* Drop an anon_vma reference if we took one */
>>       if (anon_vma)
>>           put_anon_vma(anon_vma);
>>       folio_unlock(src);
>> -out:
>>       /*
>>        * If migration is successful, decrease refcount of dst,
>>        * which will not free the page because new page owner increased
>> @@ -1159,19 +1230,15 @@ static int __unmap_and_move(struct folio 
>> *src, struct folio *dst,
>>       return rc;
>>   }
>>   -/*
>> - * Obtain the lock on folio, remove all ptes and migrate the folio
>> - * to the newly allocated folio in dst.
>> - */
>> -static int unmap_and_move(new_page_t get_new_page,
>> -                   free_page_t put_new_page,
>> -                   unsigned long private, struct folio *src,
>> -                   int force, enum migrate_mode mode,
>> -                   enum migrate_reason reason,
>> -                   struct list_head *ret)
>> +/* Obtain the lock on page, remove all ptes. */
>> +static int migrate_folio_unmap(new_page_t get_new_page, free_page_t 
>> put_new_page,
>> +                   unsigned long private, struct folio *src,
>> +                   struct folio **dstp, int force,
>> +                   enum migrate_mode mode, enum migrate_reason reason,
>> +                   struct list_head *ret)
>>   {
>>       struct folio *dst;
>> -    int rc = MIGRATEPAGE_SUCCESS;
>> +    int rc = MIGRATEPAGE_UNMAP;
>>       struct page *newpage = NULL;
>>         if (!thp_migration_supported() && folio_test_transhuge(src))
>> @@ -1182,20 +1249,50 @@ static int unmap_and_move(new_page_t 
>> get_new_page,
>>           folio_clear_active(src);
>>           folio_clear_unevictable(src);
>>           /* free_pages_prepare() will clear PG_isolated. */
>> -        goto out;
>> +        list_del(&src->lru);
>> +        migrate_folio_done(src, reason);
>> +        return MIGRATEPAGE_SUCCESS;
>>       }
>>         newpage = get_new_page(&src->page, private);
>>       if (!newpage)
>>           return -ENOMEM;
>>       dst = page_folio(newpage);
>> +    *dstp = dst;
>>         dst->private = NULL;
>> -    rc = __unmap_and_move(src, dst, force, mode);
>> +    rc = __migrate_folio_unmap(src, dst, force, mode);
>> +    if (rc == MIGRATEPAGE_UNMAP)
>> +        return rc;
>> +
>> +    /*
>> +     * A page that has not been migrated will have kept its
>> +     * references and be restored.
>> +     */
>> +    /* restore the folio to right list. */
>> +    if (rc != -EAGAIN)
>> +        list_move_tail(&src->lru, ret);
>> +
>> +    if (put_new_page)
>> +        put_new_page(&dst->page, private);
>> +    else
>> +        folio_put(dst);
>> +
>> +    return rc;
>> +}
>> +
>> +/* Migrate the folio to the newly allocated folio in dst. */
>> +static int migrate_folio_move(free_page_t put_new_page, unsigned 
>> long private,
>> +                  struct folio *src, struct folio *dst,
>> +                  enum migrate_mode mode, enum migrate_reason reason,
>> +                  struct list_head *ret)
>> +{
>> +    int rc;
>> +
>> +    rc = __migrate_folio_move(src, dst, mode);
>>       if (rc == MIGRATEPAGE_SUCCESS)
>>           set_page_owner_migrate_reason(&dst->page, reason);
>>   -out:
>>       if (rc != -EAGAIN) {
>>           /*
>>            * A folio that has been migrated has all references
>> @@ -1211,20 +1308,7 @@ static int unmap_and_move(new_page_t 
>> get_new_page,
>>        * we want to retry.
>>        */
>>       if (rc == MIGRATEPAGE_SUCCESS) {
>> -        /*
>> -         * Compaction can migrate also non-LRU folios which are
>> -         * not accounted to NR_ISOLATED_*. They can be recognized
>> -         * as __folio_test_movable
>> -         */
>> -        if (likely(!__folio_test_movable(src)))
>> -            mod_node_page_state(folio_pgdat(src), NR_ISOLATED_ANON +
>> -                    folio_is_file_lru(src), -folio_nr_pages(src));
>> -
>> -        if (reason != MR_MEMORY_FAILURE)
>> -            /*
>> -             * We release the folio in page_handle_poison.
>> -             */
>> -            folio_put(src);
>> +        migrate_folio_done(src, reason);
>>       } else {
>>           if (rc != -EAGAIN)
>>               list_add_tail(&src->lru, ret);
>> @@ -1516,7 +1600,7 @@ static int migrate_pages_batch(struct list_head 
>> *from, new_page_t get_new_page,
>>       int pass = 0;
>>       bool is_large = false;
>>       bool is_thp = false;
>> -    struct folio *folio, *folio2;
>> +    struct folio *folio, *folio2, *dst = NULL;
>>       int rc, nr_pages;
>>       LIST_HEAD(split_folios);
>>       bool nosplit = (reason == MR_NUMA_MISPLACED);
>> @@ -1543,9 +1627,13 @@ static int migrate_pages_batch(struct 
>> list_head *from, new_page_t get_new_page,
>>                 cond_resched();
>>   -            rc = unmap_and_move(get_new_page, put_new_page,
>> -                        private, folio, pass > 2, mode,
>> -                        reason, ret_folios);
>> +            rc = migrate_folio_unmap(get_new_page, put_new_page, 
>> private,
>> +                         folio, &dst, pass > 2, mode,
>> +                         reason, ret_folios);
>> +            if (rc == MIGRATEPAGE_UNMAP)
>> +                rc = migrate_folio_move(put_new_page, private,
>> +                            folio, dst, mode,
>> +                            reason, ret_folios);
> How to deal with the whole  pages are ummaped success,  but only part  
> pages are moved success ?

Please ignore this, i get answer from patch 5.

Reviewed-by: Xin Hao <xhao@linux.alibaba.com>

>>               /*
>>                * The rules are:
>>                *    Success: folio will be freed
diff mbox series

Patch

diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index 3ef77f52a4f0..7376074f2e1e 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -18,6 +18,7 @@  struct migration_target_control;
  * - zero on page migration success;
  */
 #define MIGRATEPAGE_SUCCESS		0
+#define MIGRATEPAGE_UNMAP		1
 
 /**
  * struct movable_operations - Driver page migration
diff --git a/mm/migrate.c b/mm/migrate.c
index 9a667039c34c..0428449149f4 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1009,11 +1009,53 @@  static int move_to_new_folio(struct folio *dst, struct folio *src,
 	return rc;
 }
 
-static int __unmap_and_move(struct folio *src, struct folio *dst,
+/*
+ * To record some information during migration, we uses some unused
+ * fields (mapping and private) of struct folio of the newly allocated
+ * destination folio.  This is safe because nobody is using them
+ * except us.
+ */
+static void __migrate_folio_record(struct folio *dst,
+				   unsigned long page_was_mapped,
+				   struct anon_vma *anon_vma)
+{
+	dst->mapping = (void *)anon_vma;
+	dst->private = (void *)page_was_mapped;
+}
+
+static void __migrate_folio_extract(struct folio *dst,
+				   int *page_was_mappedp,
+				   struct anon_vma **anon_vmap)
+{
+	*anon_vmap = (void *)dst->mapping;
+	*page_was_mappedp = (unsigned long)dst->private;
+	dst->mapping = NULL;
+	dst->private = NULL;
+}
+
+/* Cleanup src folio upon migration success */
+static void migrate_folio_done(struct folio *src,
+			       enum migrate_reason reason)
+{
+	/*
+	 * Compaction can migrate also non-LRU pages which are
+	 * not accounted to NR_ISOLATED_*. They can be recognized
+	 * as __PageMovable
+	 */
+	if (likely(!__folio_test_movable(src)))
+		mod_node_page_state(folio_pgdat(src), NR_ISOLATED_ANON +
+				    folio_is_file_lru(src), -folio_nr_pages(src));
+
+	if (reason != MR_MEMORY_FAILURE)
+		/* We release the page in page_handle_poison. */
+		folio_put(src);
+}
+
+static int __migrate_folio_unmap(struct folio *src, struct folio *dst,
 				int force, enum migrate_mode mode)
 {
 	int rc = -EAGAIN;
-	bool page_was_mapped = false;
+	int page_was_mapped = 0;
 	struct anon_vma *anon_vma = NULL;
 	bool is_lru = !__PageMovable(&src->page);
 
@@ -1089,8 +1131,8 @@  static int __unmap_and_move(struct folio *src, struct folio *dst,
 		goto out_unlock;
 
 	if (unlikely(!is_lru)) {
-		rc = move_to_new_folio(dst, src, mode);
-		goto out_unlock_both;
+		__migrate_folio_record(dst, page_was_mapped, anon_vma);
+		return MIGRATEPAGE_UNMAP;
 	}
 
 	/*
@@ -1115,11 +1157,42 @@  static int __unmap_and_move(struct folio *src, struct folio *dst,
 		VM_BUG_ON_FOLIO(folio_test_anon(src) &&
 			       !folio_test_ksm(src) && !anon_vma, src);
 		try_to_migrate(src, 0);
-		page_was_mapped = true;
+		page_was_mapped = 1;
 	}
 
-	if (!folio_mapped(src))
-		rc = move_to_new_folio(dst, src, mode);
+	if (!folio_mapped(src)) {
+		__migrate_folio_record(dst, page_was_mapped, anon_vma);
+		return MIGRATEPAGE_UNMAP;
+	}
+
+	if (page_was_mapped)
+		remove_migration_ptes(src, src, false);
+
+out_unlock_both:
+	folio_unlock(dst);
+out_unlock:
+	/* Drop an anon_vma reference if we took one */
+	if (anon_vma)
+		put_anon_vma(anon_vma);
+	folio_unlock(src);
+out:
+
+	return rc;
+}
+
+static int __migrate_folio_move(struct folio *src, struct folio *dst,
+				enum migrate_mode mode)
+{
+	int rc;
+	int page_was_mapped = 0;
+	struct anon_vma *anon_vma = NULL;
+	bool is_lru = !__PageMovable(&src->page);
+
+	__migrate_folio_extract(dst, &page_was_mapped, &anon_vma);
+
+	rc = move_to_new_folio(dst, src, mode);
+	if (unlikely(!is_lru))
+		goto out_unlock_both;
 
 	/*
 	 * When successful, push dst to LRU immediately: so that if it
@@ -1142,12 +1215,10 @@  static int __unmap_and_move(struct folio *src, struct folio *dst,
 
 out_unlock_both:
 	folio_unlock(dst);
-out_unlock:
 	/* Drop an anon_vma reference if we took one */
 	if (anon_vma)
 		put_anon_vma(anon_vma);
 	folio_unlock(src);
-out:
 	/*
 	 * If migration is successful, decrease refcount of dst,
 	 * which will not free the page because new page owner increased
@@ -1159,19 +1230,15 @@  static int __unmap_and_move(struct folio *src, struct folio *dst,
 	return rc;
 }
 
-/*
- * Obtain the lock on folio, remove all ptes and migrate the folio
- * to the newly allocated folio in dst.
- */
-static int unmap_and_move(new_page_t get_new_page,
-				   free_page_t put_new_page,
-				   unsigned long private, struct folio *src,
-				   int force, enum migrate_mode mode,
-				   enum migrate_reason reason,
-				   struct list_head *ret)
+/* Obtain the lock on page, remove all ptes. */
+static int migrate_folio_unmap(new_page_t get_new_page, free_page_t put_new_page,
+			       unsigned long private, struct folio *src,
+			       struct folio **dstp, int force,
+			       enum migrate_mode mode, enum migrate_reason reason,
+			       struct list_head *ret)
 {
 	struct folio *dst;
-	int rc = MIGRATEPAGE_SUCCESS;
+	int rc = MIGRATEPAGE_UNMAP;
 	struct page *newpage = NULL;
 
 	if (!thp_migration_supported() && folio_test_transhuge(src))
@@ -1182,20 +1249,50 @@  static int unmap_and_move(new_page_t get_new_page,
 		folio_clear_active(src);
 		folio_clear_unevictable(src);
 		/* free_pages_prepare() will clear PG_isolated. */
-		goto out;
+		list_del(&src->lru);
+		migrate_folio_done(src, reason);
+		return MIGRATEPAGE_SUCCESS;
 	}
 
 	newpage = get_new_page(&src->page, private);
 	if (!newpage)
 		return -ENOMEM;
 	dst = page_folio(newpage);
+	*dstp = dst;
 
 	dst->private = NULL;
-	rc = __unmap_and_move(src, dst, force, mode);
+	rc = __migrate_folio_unmap(src, dst, force, mode);
+	if (rc == MIGRATEPAGE_UNMAP)
+		return rc;
+
+	/*
+	 * A page that has not been migrated will have kept its
+	 * references and be restored.
+	 */
+	/* restore the folio to right list. */
+	if (rc != -EAGAIN)
+		list_move_tail(&src->lru, ret);
+
+	if (put_new_page)
+		put_new_page(&dst->page, private);
+	else
+		folio_put(dst);
+
+	return rc;
+}
+
+/* Migrate the folio to the newly allocated folio in dst. */
+static int migrate_folio_move(free_page_t put_new_page, unsigned long private,
+			      struct folio *src, struct folio *dst,
+			      enum migrate_mode mode, enum migrate_reason reason,
+			      struct list_head *ret)
+{
+	int rc;
+
+	rc = __migrate_folio_move(src, dst, mode);
 	if (rc == MIGRATEPAGE_SUCCESS)
 		set_page_owner_migrate_reason(&dst->page, reason);
 
-out:
 	if (rc != -EAGAIN) {
 		/*
 		 * A folio that has been migrated has all references
@@ -1211,20 +1308,7 @@  static int unmap_and_move(new_page_t get_new_page,
 	 * we want to retry.
 	 */
 	if (rc == MIGRATEPAGE_SUCCESS) {
-		/*
-		 * Compaction can migrate also non-LRU folios which are
-		 * not accounted to NR_ISOLATED_*. They can be recognized
-		 * as __folio_test_movable
-		 */
-		if (likely(!__folio_test_movable(src)))
-			mod_node_page_state(folio_pgdat(src), NR_ISOLATED_ANON +
-					folio_is_file_lru(src), -folio_nr_pages(src));
-
-		if (reason != MR_MEMORY_FAILURE)
-			/*
-			 * We release the folio in page_handle_poison.
-			 */
-			folio_put(src);
+		migrate_folio_done(src, reason);
 	} else {
 		if (rc != -EAGAIN)
 			list_add_tail(&src->lru, ret);
@@ -1516,7 +1600,7 @@  static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page,
 	int pass = 0;
 	bool is_large = false;
 	bool is_thp = false;
-	struct folio *folio, *folio2;
+	struct folio *folio, *folio2, *dst = NULL;
 	int rc, nr_pages;
 	LIST_HEAD(split_folios);
 	bool nosplit = (reason == MR_NUMA_MISPLACED);
@@ -1543,9 +1627,13 @@  static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page,
 
 			cond_resched();
 
-			rc = unmap_and_move(get_new_page, put_new_page,
-					    private, folio, pass > 2, mode,
-					    reason, ret_folios);
+			rc = migrate_folio_unmap(get_new_page, put_new_page, private,
+						 folio, &dst, pass > 2, mode,
+						 reason, ret_folios);
+			if (rc == MIGRATEPAGE_UNMAP)
+				rc = migrate_folio_move(put_new_page, private,
+							folio, dst, mode,
+							reason, ret_folios);
 			/*
 			 * The rules are:
 			 *	Success: folio will be freed