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([43.11.56.84]) by jpmta-ob1.noc.sony.co.jp with ESMTP; 19 Nov 2025 14:46:09 +0900 From: Yohei Kojima To: Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" Cc: Yohei Kojima , linux-kernel@vger.kernel.org Subject: [PATCH] x86/mm: Fix {split,collapse}_page_count to use PTRS_PER_PMD if necessary Date: Wed, 19 Nov 2025 14:46:19 +0900 Message-ID: <3d8bca84657d8b22a007a052258be1fb2a7c917d.1763531142.git.Yohei.Kojima@sony.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Before this commit, split_page_count() and collapse_page_count() updated direct_pages_count using PTRS_PER_PTE constant. However, these functions should use PTRS_PER_PMD if 1G page is splitted into 2M pages and vice versa because 2M direct pages are managed by PMD. This commit fixes {split,collapse}_page_count() to use PTRS_PER_PMD in such cases. The basic behavior of these functions are unchanged because x86's 1G page split and collapse are currently only supported on 64-bit environment where PTRS_PER_PTE and PTRS_PER_PMD are both 512. --- arch/x86/mm/pat/set_memory.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/arch/x86/mm/pat/set_memory.c b/arch/x86/mm/pat/set_memory.c index 970981893c9b..aa6fa4894edb 100644 --- a/arch/x86/mm/pat/set_memory.c +++ b/arch/x86/mm/pat/set_memory.c @@ -97,25 +97,29 @@ static void split_page_count(int level) return; =20 direct_pages_count[level]--; - if (system_state =3D=3D SYSTEM_RUNNING) { - if (level =3D=3D PG_LEVEL_2M) + if (level =3D=3D PG_LEVEL_2M) { + if (system_state =3D=3D SYSTEM_RUNNING) count_vm_event(DIRECT_MAP_LEVEL2_SPLIT); - else if (level =3D=3D PG_LEVEL_1G) + direct_pages_count[PG_LEVEL_4K] +=3D PTRS_PER_PTE; + } else if (level =3D=3D PG_LEVEL_1G) { + if (system_state =3D=3D SYSTEM_RUNNING) count_vm_event(DIRECT_MAP_LEVEL3_SPLIT); + direct_pages_count[PG_LEVEL_2M] +=3D PTRS_PER_PMD; } - direct_pages_count[level - 1] +=3D PTRS_PER_PTE; } =20 static void collapse_page_count(int level) { direct_pages_count[level]++; - if (system_state =3D=3D SYSTEM_RUNNING) { - if (level =3D=3D PG_LEVEL_2M) + if (level =3D=3D PG_LEVEL_2M) { + if (system_state =3D=3D SYSTEM_RUNNING) count_vm_event(DIRECT_MAP_LEVEL2_COLLAPSE); - else if (level =3D=3D PG_LEVEL_1G) + direct_pages_count[PG_LEVEL_4K] -=3D PTRS_PER_PTE; + } else if (level =3D=3D PG_LEVEL_1G) { + if (system_state =3D=3D SYSTEM_RUNNING) count_vm_event(DIRECT_MAP_LEVEL3_COLLAPSE); + direct_pages_count[PG_LEVEL_2M] -=3D PTRS_PER_PMD; } - direct_pages_count[level - 1] -=3D PTRS_PER_PTE; } =20 void arch_report_meminfo(struct seq_file *m) --=20 2.43.0