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Date:   Fri, 24 Jun 2022 17:36:35 +0000
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Subject: [RFC PATCH 05/26] hugetlb: add CONFIG_HUGETLB_HIGH_GRANULARITY_MAPPING
From:   James Houghton <jthoughton@google.com>
To:     Mike Kravetz <mike.kravetz@oracle.com>,
        Muchun Song <songmuchun@bytedance.com>,
        Peter Xu <peterx@redhat.com>
Cc:     David Hildenbrand <david@redhat.com>,
        David Rientjes <rientjes@google.com>,
        Axel Rasmussen <axelrasmussen@google.com>,
        Mina Almasry <almasrymina@google.com>,
        Jue Wang <juew@google.com>,
        Manish Mishra <manish.mishra@nutanix.com>,
        "Dr . David Alan Gilbert" <dgilbert@redhat.com>,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        James Houghton <jthoughton@google.com>
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This adds the Kconfig to enable or disable high-granularity mapping. It
is enabled by default for architectures that use
ARCH_WANT_GENERAL_HUGETLB.

There is also an arch-specific config ARCH_HAS_SPECIAL_HUGETLB_HGM which
controls whether or not the architecture has been updated to support
HGM if it doesn't use general HugeTLB.

Signed-off-by: James Houghton <jthoughton@google.com>
---
 fs/Kconfig | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/fs/Kconfig b/fs/Kconfig
index 5976eb33535f..d76c7d812656 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -268,6 +268,13 @@ config HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON
 	  to enable optimizing vmemmap pages of HugeTLB by default. It can then
 	  be disabled on the command line via hugetlb_free_vmemmap=off.
 
+config ARCH_HAS_SPECIAL_HUGETLB_HGM
+	bool
+
+config HUGETLB_HIGH_GRANULARITY_MAPPING
+	def_bool ARCH_WANT_GENERAL_HUGETLB || ARCH_HAS_SPECIAL_HUGETLB_HGM
+	depends on HUGETLB_PAGE
+
 config MEMFD_CREATE
 	def_bool TMPFS || HUGETLBFS
 
-- 
2.37.0.rc0.161.g10f37bed90-goog