On 27/06/2023 03:27, Yu Zhao wrote:

On Mon, Jun 26, 2023 at 11:14 AM Ryan Roberts [off-list ref] wrote:

quoted

Allow allocation of large folios with vma_alloc_zeroed_movable_folio().
This prepares the ground for large anonymous folios. The generic
implementation of vma_alloc_zeroed_movable_folio() now uses
clear_huge_page() to zero the allocated folio since it may now be a
non-0 order.

Currently the function is always called with order 0 and no extra gfp
flags, so no functional change intended. But a subsequent commit will
take advantage of the new parameters to allocate large folios. The extra
gfp flags will be used to control the reclaim policy.

Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
---
 arch/alpha/include/asm/page.h   |  5 +++--
 arch/arm64/include/asm/page.h   |  3 ++-
 arch/arm64/mm/fault.c           |  7 ++++---
 arch/ia64/include/asm/page.h    |  5 +++--
 arch/m68k/include/asm/page_no.h |  7 ++++---
 arch/s390/include/asm/page.h    |  5 +++--
 arch/x86/include/asm/page.h     |  5 +++--
 include/linux/highmem.h         | 23 +++++++++++++----------
 mm/memory.c                     |  5 +++--
 9 files changed, 38 insertions(+), 27 deletions(-)

diff --git a/arch/alpha/include/asm/page.h b/arch/alpha/include/asm/page.h
index 4db1ebc0ed99..6fc7fe91b6cb 100644
--- a/arch/alpha/include/asm/page.h
+++ b/arch/alpha/include/asm/page.h

@@ -17,8 +17,9 @@
 extern void clear_page(void *page);
 #define clear_user_page(page, vaddr, pg)       clear_page(page)

-#define vma_alloc_zeroed_movable_folio(vma, vaddr) \
-       vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, 0, vma, vaddr, false)
+#define vma_alloc_zeroed_movable_folio(vma, vaddr, gfp, order) \
+       vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO | (gfp), \
+                       order, vma, vaddr, false)

I don't think we need to worry about gfp if we want to make a minimum
series. There would be many discussion points around it, e.g., I
already disagree with what you chose: GFP_TRANSHUGE_LIGHT would be
more suitable than __GFP_NORETRY, and there are even better options
than GFP_TRANSHUGE_LIGHT.

OK, but disagreeing about what the GFP flags should be is different from
disagreeing about whether we need a mechanism for specifying them. Given I need
to do the changes to add `order` I thought it was sensible to add the gfp flags
at the same time.

I'll follow your advice and remove the gfp flag addition for now.

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