Re: [PATCH v3 4/4] mm/page_isolation: remove migratetype parameter from more functions.

[Zi Yan <ziy@nvidia.com>]

On 8 May 2025, at 21:56, Zi Yan wrote:

> On 8 May 2025, at 16:25, Zi Yan wrote:
>
>> On 7 May 2025, at 17:10, Zi Yan wrote:
>>
>>> migratetype is no longer overwritten during pageblock isolation,
>>> start_isolate_page_range(), has_unmovable_pages(), and
>>> set_migratetype_isolate() no longer need which migratetype to restore
>>> during isolation failure.
>>>
>>> For has_unmoable_pages(), it needs to know if the isolation is for CMA
>>> allocation, so adding CMA_ALLOCATION to isolation flags to provide the
>>> information.
>>>
>>> alloc_contig_range() no longer needs migratetype. Replace it with
>>> a newly defined acr_flags_t to tell if an allocation is for CMA. So does
>>> __alloc_contig_migrate_range().
>>>
>>> Signed-off-by: Zi Yan <ziy@nvidia.com>
>>> ---
>>>  drivers/virtio/virtio_mem.c    |  3 +--
>>>  include/linux/gfp.h            |  6 +++++-
>>>  include/linux/page-isolation.h | 15 +++++++++++---
>>>  include/trace/events/kmem.h    | 14 +++++++------
>>>  mm/cma.c                       |  2 +-
>>>  mm/memory_hotplug.c            |  1 -
>>>  mm/page_alloc.c                | 22 ++++++++++-----------
>>>  mm/page_isolation.c            | 36 ++++++++++++----------------------
>>>  8 files changed, 50 insertions(+), 49 deletions(-)
>>
>> Here is the fixup 3/3 to address the type issue reported by kernel test robot.
>>
>> From 3c439f1f09b03c8362b43c0ac05e5f174f1a6655 Mon Sep 17 00:00:00 2001
>> From: Zi Yan <ziy@nvidia.com>
>> Date: Thu, 8 May 2025 15:42:18 -0400
>> Subject: [PATCH] fixup for mm/page_isolation: remove migratetype parameter
>>  from more functions.
>>
>> 1. fixed test_pages_isolated() and __test_page_isolated_in_pageblock()
>>    signature by using the new isol_flags_t type.
>> 2. fixed test_pages_isolated() doc: flags -> isol_flags
>>
>> Signed-off-by: Zi Yan <ziy@nvidia.com>
>> ---
>>  include/linux/page-isolation.h | 2 +-
>>  mm/page_isolation.c            | 6 +++---
>>  2 files changed, 4 insertions(+), 4 deletions(-)
>
> This is the second round of fixup 1/1 to address Johannes' comment on Patch 4.
>
> From 760c00e808c74d62e8d879f281f38d6608c89296 Mon Sep 17 00:00:00 2001
> From: Zi Yan <ziy@nvidia.com>
> Date: Thu, 8 May 2025 20:54:40 -0400
> Subject: [PATCH] fixup for fixup for mm/page_isolation: remove migratetype
>  parameter from more functions.
>
> 1. change MEMORY_OFFLINE and CMA_ALLOCATION to isolate_mode_t enums.
> 2. rename isol_flags_t to isolate_flags_t.
> 2. REPORT_FAILURE becomes the only isolate_flags_t.
>
> Signed-off-by: Zi Yan <ziy@nvidia.com>
> ---
>  include/linux/page-isolation.h | 26 +++++++++++++++++---------
>  mm/memory_hotplug.c            |  2 +-
>  mm/page_alloc.c                |  3 ++-
>  mm/page_isolation.c            | 31 ++++++++++++++++++-------------
>  4 files changed, 38 insertions(+), 24 deletions(-)
>

This fixup has missing pieces. Let me send another one.

> diff --git a/include/linux/page-isolation.h b/include/linux/page-isolation.h
> index 20c3f98b5afb..29b4ddcaea7a 100644
> --- a/include/linux/page-isolation.h
> +++ b/include/linux/page-isolation.h
> @@ -22,17 +22,25 @@ static inline bool is_migrate_isolate(int migratetype)
>  }
>  #endif
>
> +/*
> + * Isolation modes:
> + * ISOLATE_MODE_NONE - isolate for other purposes than those below
> + * MEMORY_OFFLINE    - isolate to offline (!allocate) memory e.g., skip over
> + *		       PageHWPoison() pages and PageOffline() pages.
> + * CMA_ALLOCATION    - isolate for CMA allocations
> + */
> +enum isolate_mode_t {
> +	ISOLATE_MODE_NONE,
> +	MEMORY_OFFLINE,
> +	CMA_ALLOCATION,
> +};
> +
>  /*
>   * Isolation flags:
> - * MEMORY_OFFLINE - isolate to offline (!allocate) memory e.g., skip over
> - *		    PageHWPoison() pages and PageOffline() pages.
>   * REPORT_FAILURE - report details about the failure to isolate the range
> - * CMA_ALLOCATION - isolate for CMA allocations
>   */
> -typedef unsigned int __bitwise isol_flags_t;
> -#define MEMORY_OFFLINE		((__force isol_flags_t)BIT(0))
> -#define REPORT_FAILURE		((__force isol_flags_t)BIT(1))
> -#define CMA_ALLOCATION		((__force isol_flags_t)BIT(2))
> +typedef unsigned int __bitwise isolate_flags_t;
> +#define REPORT_FAILURE		((__force isolate_flags_t)BIT(0))
>
>  void set_pageblock_migratetype(struct page *page, int migratetype);
>
> @@ -40,10 +48,10 @@ bool pageblock_isolate_and_move_free_pages(struct zone *zone, struct page *page)
>  bool pageblock_unisolate_and_move_free_pages(struct zone *zone, struct page *page);
>
>  int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
> -			     isol_flags_t flags);
> +			     isolate_mode_t mode, isolate_flags_t flags);
>
>  void undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn);
>
>  int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn,
> -			isol_flags_t isol_flags);
> +			isolate_flags_t isol_flags);
>  #endif
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 155f0b4ff299..3dab006a537e 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -2005,7 +2005,7 @@ int offline_pages(unsigned long start_pfn, unsigned long nr_pages,
>
>  	/* set above range as isolated */
>  	ret = start_isolate_page_range(start_pfn, end_pfn,
> -				       MEMORY_OFFLINE | REPORT_FAILURE);
> +				       MEMORY_OFFLINE, REPORT_FAILURE);
>  	if (ret) {
>  		reason = "failure to isolate range";
>  		goto failed_removal_pcplists_disabled;
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 51d66f86b93d..3f208f8656f4 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -6787,7 +6787,8 @@ int alloc_contig_range_noprof(unsigned long start, unsigned long end,
>  	 */
>
>  	ret = start_isolate_page_range(start, end,
> -			(alloc_flags & ACR_CMA) ? CMA_ALLOCATION : 0);
> +		(alloc_flags & ACR_CMA) ? CMA_ALLOCATION : ISOLATE_MODE_NONE,
> +		0);
>  	if (ret)
>  		goto done;
>
> diff --git a/mm/page_isolation.c b/mm/page_isolation.c
> index 5f00d7113766..fd4818862654 100644
> --- a/mm/page_isolation.c
> +++ b/mm/page_isolation.c
> @@ -48,7 +48,7 @@ static inline void set_pageblock_isolate(struct page *page)
>   *
>   */
>  static struct page *has_unmovable_pages(unsigned long start_pfn, unsigned long end_pfn,
> -				isol_flags_t flags)
> +				isolate_mode_t mode, isolate_flags_t flags)
>  {
>  	struct page *page = pfn_to_page(start_pfn);
>  	struct zone *zone = page_zone(page);
> @@ -63,7 +63,7 @@ static struct page *has_unmovable_pages(unsigned long start_pfn, unsigned long e
>  		 * isolate CMA pageblocks even when they are not movable in fact
>  		 * so consider them movable here.
>  		 */
> -		if (flags & CMA_ALLOCATION)
> +		if (mode == CMA_ALLOCATION)
>  			return NULL;
>
>  		return page;
> @@ -168,8 +168,9 @@ static struct page *has_unmovable_pages(unsigned long start_pfn, unsigned long e
>   * present in [start_pfn, end_pfn). The pageblock must intersect with
>   * [start_pfn, end_pfn).
>   */
> -static int set_migratetype_isolate(struct page *page, isol_flags_t isol_flags,
> -			unsigned long start_pfn, unsigned long end_pfn)
> +static int set_migratetype_isolate(struct page *page, isolate_mode_t mode,
> +			isolate_flags_t isol_flags, unsigned long start_pfn,
> +			unsigned long end_pfn)
>  {
>  	struct zone *zone = page_zone(page);
>  	struct page *unmovable;
> @@ -203,7 +204,7 @@ static int set_migratetype_isolate(struct page *page, isol_flags_t isol_flags,
>  				  end_pfn);
>
>  	unmovable = has_unmovable_pages(check_unmovable_start, check_unmovable_end,
> -			isol_flags);
> +			mode, isol_flags);
>  	if (!unmovable) {
>  		if (!pageblock_isolate_and_move_free_pages(zone, page)) {
>  			spin_unlock_irqrestore(&zone->lock, flags);
> @@ -309,6 +310,7 @@ __first_valid_page(unsigned long pfn, unsigned long nr_pages)
>   * isolate_single_pageblock() -- tries to isolate a pageblock that might be
>   * within a free or in-use page.
>   * @boundary_pfn:		pageblock-aligned pfn that a page might cross
> + * @mode:			isolation mode
>   * @flags:			isolation flags
>   * @isolate_before:	isolate the pageblock before the boundary_pfn
>   * @skip_isolation:	the flag to skip the pageblock isolation in second
> @@ -327,7 +329,8 @@ __first_valid_page(unsigned long pfn, unsigned long nr_pages)
>   * either. The function handles this by splitting the free page or migrating
>   * the in-use page then splitting the free page.
>   */
> -static int isolate_single_pageblock(unsigned long boundary_pfn, isol_flags_t flags,
> +static int isolate_single_pageblock(unsigned long boundary_pfn,
> +			isolate_mode_t mode, isolate_flags_t flags,
>  			bool isolate_before, bool skip_isolation)
>  {
>  	unsigned long start_pfn;
> @@ -357,7 +360,8 @@ static int isolate_single_pageblock(unsigned long boundary_pfn, isol_flags_t fla
>  		VM_BUG_ON(!get_pageblock_isolate(pfn_to_page(isolate_pageblock)));
>  	} else {
>  		ret = set_migratetype_isolate(pfn_to_page(isolate_pageblock),
> -				flags, isolate_pageblock, isolate_pageblock + pageblock_nr_pages);
> +				mode, flags, isolate_pageblock,
> +				isolate_pageblock + pageblock_nr_pages);
>
>  		if (ret)
>  			return ret;
> @@ -455,6 +459,7 @@ static int isolate_single_pageblock(unsigned long boundary_pfn, isol_flags_t fla
>   * start_isolate_page_range() - mark page range MIGRATE_ISOLATE
>   * @start_pfn:		The first PFN of the range to be isolated.
>   * @end_pfn:		The last PFN of the range to be isolated.
> + * @mode:		isolation mode
>   * @flags:		isolation flags
>   *
>   * Making page-allocation-type to be MIGRATE_ISOLATE means free pages in
> @@ -488,7 +493,7 @@ static int isolate_single_pageblock(unsigned long boundary_pfn, isol_flags_t fla
>   * Return: 0 on success and -EBUSY if any part of range cannot be isolated.
>   */
>  int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
> -			     isol_flags_t flags)
> +			     isolate_mode_t mode, isolate_flags_t flags)
>  {
>  	unsigned long pfn;
>  	struct page *page;
> @@ -499,7 +504,7 @@ int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
>  	bool skip_isolation = false;
>
>  	/* isolate [isolate_start, isolate_start + pageblock_nr_pages) pageblock */
> -	ret = isolate_single_pageblock(isolate_start, flags, false,
> +	ret = isolate_single_pageblock(isolate_start, mode, flags, false,
>  			skip_isolation);
>  	if (ret)
>  		return ret;
> @@ -508,7 +513,7 @@ int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
>  		skip_isolation = true;
>
>  	/* isolate [isolate_end - pageblock_nr_pages, isolate_end) pageblock */
> -	ret = isolate_single_pageblock(isolate_end, flags, true,
> +	ret = isolate_single_pageblock(isolate_end, mode, flags, true,
>  			skip_isolation);
>  	if (ret) {
>  		unset_migratetype_isolate(pfn_to_page(isolate_start));
> @@ -520,7 +525,7 @@ int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
>  	     pfn < isolate_end - pageblock_nr_pages;
>  	     pfn += pageblock_nr_pages) {
>  		page = __first_valid_page(pfn, pageblock_nr_pages);
> -		if (page && set_migratetype_isolate(page, flags,
> +		if (page && set_migratetype_isolate(page, mode, flags,
>  					start_pfn, end_pfn)) {
>  			undo_isolate_page_range(isolate_start, pfn);
>  			unset_migratetype_isolate(
> @@ -563,7 +568,7 @@ void undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn)
>   */
>  static unsigned long
>  __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn,
> -				  isol_flags_t flags)
> +				  isolate_flags_t flags)
>  {
>  	struct page *page;
>
> @@ -610,7 +615,7 @@ __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn,
>   * Returns 0 if true, -EBUSY if one or more pages are in use.
>   */
>  int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn,
> -			isol_flags_t isol_flags)
> +			isolate_flags_t isol_flags)
>  {
>  	unsigned long pfn, flags;
>  	struct page *page;
> -- 
> 2.47.2
>
>
>
> --
> Best Regards,
> Yan, Zi


--
Best Regards,
Yan, Zi