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From: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
To: "rppt@kernel.org" <rppt@kernel.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"peterz@infradead.org" <peterz@infradead.org>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
	"x86@kernel.org" <x86@kernel.org>,
	"hpa@zytor.com" <hpa@zytor.com>,
	"mingo@redhat.com" <mingo@redhat.com>,
	"rppt@linux.ibm.com" <rppt@linux.ibm.com>,
	"Lutomirski, Andy" <luto@kernel.org>,
	"bp@alien8.de" <bp@alien8.de>
Subject: Re: [PATCH 4/4] x86/mm: replace GFP_ATOMIC with GFP_KERNEL for direct map allocations
Date: Fri, 12 Nov 2021 22:39:11 +0000	[thread overview]
Message-ID: <29f9155d0d164d349784b4c40cd806bc1129005d.camel@intel.com> (raw)
In-Reply-To: <YY5eYEzsp0UKn4Xr@kernel.org>

On Fri, 2021-11-12 at 14:30 +0200, Mike Rapoport wrote:
> The fixmap is less 2M so all the page tables will be allocated from
> gpt
> cache/memblock so __set_fixmap() will be essentially a call to
> set_pte().

If you configure CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP it can be larger.

> 
> I'll see how to ensure that page tables for ghex fixmaps are
> explicitly
> preallocated at init time.
>  

Investigating a bit further, fixmap pte's are allocated statically with
level1_fixmap_pgt, so set_fixmap() should never call spp_getpage() pre
or post after_bootmem. So I guess GFP_KERNEL shouldn't come into play
for all the fixmap callers.

Thanks!

Reviewed-by: Rick Edgecombe <rick.p.edgecombe@intel.com>

      reply	other threads:[~2021-11-12 22:39 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-11 11:02 [PATCH 0/4] x86/mm: replace GFP_ATOMIC with GFP_KERNEL for direct map allocations Mike Rapoport
2021-11-11 11:02 ` [PATCH 1/4] x86/mm: make init_trampoline_kaslr() __init Mike Rapoport
2021-11-11 20:46   ` Edgecombe, Rick P
2021-11-11 11:02 ` [PATCH 2/4] x86/mm: make kernel_physical_mapping_change() __init Mike Rapoport
2021-11-11 20:47   ` Edgecombe, Rick P
2021-11-11 11:02 ` [PATCH 3/4] x86/mm: init_64: make set_pte_vaddr_p4d static Mike Rapoport
2021-11-11 20:48   ` Edgecombe, Rick P
2021-11-11 11:02 ` [PATCH 4/4] x86/mm: replace GFP_ATOMIC with GFP_KERNEL for direct map allocations Mike Rapoport
2021-11-11 15:19   ` Dave Hansen
2021-11-11 15:57     ` Mike Rapoport
2021-11-11 21:35   ` Edgecombe, Rick P
2021-11-12 12:30     ` Mike Rapoport
2021-11-12 22:39       ` Edgecombe, Rick P [this message]

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