Hi,

On Mon, Jan 29, 2024 at 11:18:59AM +0530, Anshuman Khandual wrote:

On 1/25/24 22:12, Alexandru Elisei wrote:

quoted

Extend the usefulness of arch_alloc_page() by adding the gfp_flags
parameter.

Although the change here is harmless in itself, it will definitely benefit
from some additional context explaining the rationale, taking into account
why-how arch_alloc_page() got added particularly for s390 platform and how
it's going to be used in the present proposal.

arm64 will use it to reserve tag storage if the caller requested a tagged
page. Right now that means that __GFP_ZEROTAGS is set in the gfp mask, but
I'll rename it to __GFP_TAGGED in patch #18 ("arm64: mte: Rename
__GFP_ZEROTAGS to __GFP_TAGGED") [1].

[1] https://lore.kernel.org/lkml/20240125164256.4147-19-alexandru.elisei@arm.com/ (local)

Thanks,
Alex

quoted

Signed-off-by: Alexandru Elisei <redacted>
---

Changes since rfc v2:

* New patch.

 arch/s390/include/asm/page.h | 2 +-
 arch/s390/mm/page-states.c   | 2 +-
 include/linux/gfp.h          | 2 +-
 mm/page_alloc.c              | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/s390/include/asm/page.h b/arch/s390/include/asm/page.h
index 73b9c3bf377f..859f0958c574 100644
--- a/arch/s390/include/asm/page.h
+++ b/arch/s390/include/asm/page.h

@@ -163,7 +163,7 @@ static inline int page_reset_referenced(unsigned long addr)
 
 struct page;
 void arch_free_page(struct page *page, int order);
-void arch_alloc_page(struct page *page, int order);
+void arch_alloc_page(struct page *page, int order, gfp_t gfp_flags);
 
 static inline int devmem_is_allowed(unsigned long pfn)
 {

diff --git a/arch/s390/mm/page-states.c b/arch/s390/mm/page-states.c
index 01f9b39e65f5..b986c8b158e3 100644
--- a/arch/s390/mm/page-states.c
+++ b/arch/s390/mm/page-states.c

@@ -21,7 +21,7 @@ void arch_free_page(struct page *page, int order)
 	__set_page_unused(page_to_virt(page), 1UL << order);
 }
 
-void arch_alloc_page(struct page *page, int order)
+void arch_alloc_page(struct page *page, int order, gfp_t gfp_flags)
 {
 	if (!cmma_flag)
 		return;

diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index de292a007138..9e8aa3d144db 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h

@@ -172,7 +172,7 @@ static inline struct zonelist *node_zonelist(int nid, gfp_t flags)
 static inline void arch_free_page(struct page *page, int order) { }
 #endif
 #ifndef HAVE_ARCH_ALLOC_PAGE
-static inline void arch_alloc_page(struct page *page, int order) { }
+static inline void arch_alloc_page(struct page *page, int order, gfp_t gfp_flags) { }
 #endif
 
 struct page *__alloc_pages(gfp_t gfp, unsigned int order, int preferred_nid,

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 150d4f23b010..2c140abe5ee6 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c

@@ -1485,7 +1485,7 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
 	set_page_private(page, 0);
 	set_page_refcounted(page);
 
-	arch_alloc_page(page, order);
+	arch_alloc_page(page, order, gfp_flags);
 	debug_pagealloc_map_pages(page, 1 << order);
 
 	/*

Otherwise LGTM.