* [PATCH] arm64/hugetlb: fix CMA gigantic page order for non-4K PAGE_SIZE
@ 2021-10-05 20:25 Mike Kravetz
2021-10-05 20:54 ` Andrew Morton
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: Mike Kravetz @ 2021-10-05 20:25 UTC (permalink / raw)
To: linux-kernel, linux-arm-kernel, Anshuman Khandual
Cc: Will Deacon, Mark Rutland, Barry Song, Andrew Morton,
Mike Kravetz, stable
For non-4K PAGE_SIZE configs, the largest gigantic huge page size is
CONT_PMD_SHIFT order.
Fixes: abb7962adc80 ("arm64/hugetlb: Reserve CMA areas for gigantic
pages on 16K and 64K configs")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: <stable@vger.kernel.org>
---
arch/arm64/mm/hugetlbpage.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index 23505fc35324..a8158c948966 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -43,7 +43,7 @@ void __init arm64_hugetlb_cma_reserve(void)
#ifdef CONFIG_ARM64_4K_PAGES
order = PUD_SHIFT - PAGE_SHIFT;
#else
- order = CONT_PMD_SHIFT + PMD_SHIFT - PAGE_SHIFT;
+ order = CONT_PMD_SHIFT - PAGE_SHIFT;
#endif
/*
* HugeTLB CMA reservation is required for gigantic
--
2.31.1
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^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] arm64/hugetlb: fix CMA gigantic page order for non-4K PAGE_SIZE
2021-10-05 20:25 [PATCH] arm64/hugetlb: fix CMA gigantic page order for non-4K PAGE_SIZE Mike Kravetz
@ 2021-10-05 20:54 ` Andrew Morton
2021-10-05 21:28 ` Mike Kravetz
2021-10-06 7:55 ` Anshuman Khandual
2021-10-06 13:06 ` Catalin Marinas
2 siblings, 1 reply; 6+ messages in thread
From: Andrew Morton @ 2021-10-05 20:54 UTC (permalink / raw)
To: Mike Kravetz
Cc: linux-kernel, linux-arm-kernel, Anshuman Khandual, Will Deacon,
Mark Rutland, Barry Song, stable
On Tue, 5 Oct 2021 13:25:29 -0700 Mike Kravetz <mike.kravetz@oracle.com> wrote:
> For non-4K PAGE_SIZE configs, the largest gigantic huge page size is
> CONT_PMD_SHIFT order.
What are the user visible effects of this bug?
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] arm64/hugetlb: fix CMA gigantic page order for non-4K PAGE_SIZE
2021-10-05 20:54 ` Andrew Morton
@ 2021-10-05 21:28 ` Mike Kravetz
2021-10-05 23:15 ` Andrew Morton
0 siblings, 1 reply; 6+ messages in thread
From: Mike Kravetz @ 2021-10-05 21:28 UTC (permalink / raw)
To: Andrew Morton
Cc: linux-kernel, linux-arm-kernel, Anshuman Khandual, Will Deacon,
Mark Rutland, Barry Song, stable
On 10/5/21 1:54 PM, Andrew Morton wrote:
> On Tue, 5 Oct 2021 13:25:29 -0700 Mike Kravetz <mike.kravetz@oracle.com> wrote:
>
>> For non-4K PAGE_SIZE configs, the largest gigantic huge page size is
>> CONT_PMD_SHIFT order.
>
> What are the user visible effects of this bug?
>
>
Sorry,
I only recently got easy access to arm64 platforms. This is what I saw
as a user:
The largest gigantic huge page size on arm64 with 64K PAGE_SIZE 64K is
16G. Therefore, one should be able to specify 'hugetlb_cma=16G' on the
kernel command line so that 1 gigantic page can be allocated from CMA.
However, when adding such an option the following message is produced:
hugetlb_cma: cma area should be at least 8796093022208 MiB
This is because the calculation for non-4K gigantic page order is
incorrect in the arm64 specific routine arm64_hugetlb_cma_reserve().
Would you like me to send a new version with this in the commit message?
Or, is it easier for you to just add it?
--
Mike Kravetz
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] arm64/hugetlb: fix CMA gigantic page order for non-4K PAGE_SIZE
2021-10-05 21:28 ` Mike Kravetz
@ 2021-10-05 23:15 ` Andrew Morton
0 siblings, 0 replies; 6+ messages in thread
From: Andrew Morton @ 2021-10-05 23:15 UTC (permalink / raw)
To: Mike Kravetz
Cc: linux-kernel, linux-arm-kernel, Anshuman Khandual, Will Deacon,
Mark Rutland, Barry Song, stable
On Tue, 5 Oct 2021 14:28:03 -0700 Mike Kravetz <mike.kravetz@oracle.com> wrote:
> On 10/5/21 1:54 PM, Andrew Morton wrote:
> > On Tue, 5 Oct 2021 13:25:29 -0700 Mike Kravetz <mike.kravetz@oracle.com> wrote:
> >
> >> For non-4K PAGE_SIZE configs, the largest gigantic huge page size is
> >> CONT_PMD_SHIFT order.
> >
> > What are the user visible effects of this bug?
> >
> >
>
> Sorry,
> I only recently got easy access to arm64 platforms. This is what I saw
> as a user:
>
> The largest gigantic huge page size on arm64 with 64K PAGE_SIZE 64K is
> 16G. Therefore, one should be able to specify 'hugetlb_cma=16G' on the
> kernel command line so that 1 gigantic page can be allocated from CMA.
> However, when adding such an option the following message is produced:
>
> hugetlb_cma: cma area should be at least 8796093022208 MiB
>
> This is because the calculation for non-4K gigantic page order is
> incorrect in the arm64 specific routine arm64_hugetlb_cma_reserve().
Cool, thanks.
> Would you like me to send a new version with this in the commit message?
> Or, is it easier for you to just add it?
I assumed that it would be merged via the same path as the offending
abb7962adc80. Catalin's arm tree, it appears.
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] arm64/hugetlb: fix CMA gigantic page order for non-4K PAGE_SIZE
2021-10-05 20:25 [PATCH] arm64/hugetlb: fix CMA gigantic page order for non-4K PAGE_SIZE Mike Kravetz
2021-10-05 20:54 ` Andrew Morton
@ 2021-10-06 7:55 ` Anshuman Khandual
2021-10-06 13:06 ` Catalin Marinas
2 siblings, 0 replies; 6+ messages in thread
From: Anshuman Khandual @ 2021-10-06 7:55 UTC (permalink / raw)
To: Mike Kravetz, linux-kernel, linux-arm-kernel
Cc: Will Deacon, Mark Rutland, Barry Song, Andrew Morton, stable
On 10/6/21 1:55 AM, Mike Kravetz wrote:
> For non-4K PAGE_SIZE configs, the largest gigantic huge page size is
> CONT_PMD_SHIFT order.
>
> Fixes: abb7962adc80 ("arm64/hugetlb: Reserve CMA areas for gigantic
> pages on 16K and 64K configs")
> Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
> Cc: <stable@vger.kernel.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
> arch/arm64/mm/hugetlbpage.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
> index 23505fc35324..a8158c948966 100644
> --- a/arch/arm64/mm/hugetlbpage.c
> +++ b/arch/arm64/mm/hugetlbpage.c
> @@ -43,7 +43,7 @@ void __init arm64_hugetlb_cma_reserve(void)
> #ifdef CONFIG_ARM64_4K_PAGES
> order = PUD_SHIFT - PAGE_SHIFT;
> #else
> - order = CONT_PMD_SHIFT + PMD_SHIFT - PAGE_SHIFT;
> + order = CONT_PMD_SHIFT - PAGE_SHIFT;
> #endif
> /*
> * HugeTLB CMA reservation is required for gigantic
>
The commit a1634a542f74 ("arm64/mm: Redefine CONT_{PTE, PMD}_SHIFT")
which got merged during the exact same week, broke the above commit
as both were in flight. The commit here updated hugetlbpage_init()
but did not update the new incoming arm64_hugetlb_cma_reserve().
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] arm64/hugetlb: fix CMA gigantic page order for non-4K PAGE_SIZE
2021-10-05 20:25 [PATCH] arm64/hugetlb: fix CMA gigantic page order for non-4K PAGE_SIZE Mike Kravetz
2021-10-05 20:54 ` Andrew Morton
2021-10-06 7:55 ` Anshuman Khandual
@ 2021-10-06 13:06 ` Catalin Marinas
2 siblings, 0 replies; 6+ messages in thread
From: Catalin Marinas @ 2021-10-06 13:06 UTC (permalink / raw)
To: Mike Kravetz, Anshuman Khandual, linux-kernel, linux-arm-kernel
Cc: Will Deacon, Andrew Morton, stable, Mark Rutland, Barry Song
On Tue, 5 Oct 2021 13:25:29 -0700, Mike Kravetz wrote:
> For non-4K PAGE_SIZE configs, the largest gigantic huge page size is
> CONT_PMD_SHIFT order.
Applied to arm64 (for-next/fixes), thanks!
[1/1] arm64/hugetlb: fix CMA gigantic page order for non-4K PAGE_SIZE
https://git.kernel.org/arm64/c/0350419b14b9
--
Catalin
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^ permalink raw reply [flat|nested] 6+ messages in thread
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2021-10-05 20:25 [PATCH] arm64/hugetlb: fix CMA gigantic page order for non-4K PAGE_SIZE Mike Kravetz
2021-10-05 20:54 ` Andrew Morton
2021-10-05 21:28 ` Mike Kravetz
2021-10-05 23:15 ` Andrew Morton
2021-10-06 7:55 ` Anshuman Khandual
2021-10-06 13:06 ` Catalin Marinas
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