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authorDavid Hildenbrand <david@redhat.com>2024-07-26 17:07:26 +0200
committerAndrew Morton <akpm@linux-foundation.org>2024-09-01 20:25:51 -0700
commit394290cba9664ed3ab80d0e247402102a9b7287a (patch)
treeb599b899efc87759be9c0fcac65147217fda1c7e /arch/x86/xen
parent57979fabff554bf4d1edeeee69251b22ca9bf55e (diff)
mm: turn USE_SPLIT_PTE_PTLOCKS / USE_SPLIT_PTE_PTLOCKS into Kconfig options
Patch series "mm: split PTE/PMD PT table Kconfig cleanups+clarifications". This series is a follow up to the fixes: "[PATCH v1 0/2] mm/hugetlb: fix hugetlb vs. core-mm PT locking" When working on the fixes, I wondered why 8xx is fine (-> never uses split PT locks) and how PT locking even works properly with PMD page table sharing (-> always requires split PMD PT locks). Let's improve the split PT lock detection, make hugetlb properly depend on it and make 8xx bail out if it would ever get enabled by accident. As an alternative to patch #3 we could extend the Kconfig SPLIT_PTE_PTLOCKS option from patch #2 -- but enforcing it closer to the code that actually implements it feels a bit nicer for documentation purposes, and there is no need to actually disable it because it should always be disabled (!SMP). Did a bunch of cross-compilations to make sure that split PTE/PMD PT locks are still getting used where we would expect them. [1] https://lkml.kernel.org/r/20240725183955.2268884-1-david@redhat.com This patch (of 3): Let's clean that up a bit and prepare for depending on CONFIG_SPLIT_PMD_PTLOCKS in other Kconfig options. More cleanups would be reasonable (like the arch-specific "depends on" for CONFIG_SPLIT_PTE_PTLOCKS), but we'll leave that for another day. Link: https://lkml.kernel.org/r/20240726150728.3159964-1-david@redhat.com Link: https://lkml.kernel.org/r/20240726150728.3159964-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Reviewed-by: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Borislav Petkov <bp@alien8.de> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Muchun Song <muchun.song@linux.dev> Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Peter Xu <peterx@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'arch/x86/xen')
-rw-r--r--arch/x86/xen/mmu_pv.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c
index f1ce39d6d32c..f4a316894bbb 100644
--- a/arch/x86/xen/mmu_pv.c
+++ b/arch/x86/xen/mmu_pv.c
@@ -665,7 +665,7 @@ static spinlock_t *xen_pte_lock(struct page *page, struct mm_struct *mm)
{
spinlock_t *ptl = NULL;
-#if USE_SPLIT_PTE_PTLOCKS
+#if defined(CONFIG_SPLIT_PTE_PTLOCKS)
ptl = ptlock_ptr(page_ptdesc(page));
spin_lock_nest_lock(ptl, &mm->page_table_lock);
#endif
@@ -1553,7 +1553,8 @@ static inline void xen_alloc_ptpage(struct mm_struct *mm, unsigned long pfn,
__set_pfn_prot(pfn, PAGE_KERNEL_RO);
- if (level == PT_PTE && USE_SPLIT_PTE_PTLOCKS && !pinned)
+ if (level == PT_PTE && IS_ENABLED(CONFIG_SPLIT_PTE_PTLOCKS) &&
+ !pinned)
__pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE, pfn);
xen_mc_issue(XEN_LAZY_MMU);
@@ -1581,7 +1582,7 @@ static inline void xen_release_ptpage(unsigned long pfn, unsigned level)
if (pinned) {
xen_mc_batch();
- if (level == PT_PTE && USE_SPLIT_PTE_PTLOCKS)
+ if (level == PT_PTE && IS_ENABLED(CONFIG_SPLIT_PTE_PTLOCKS))
__pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, pfn);
__set_pfn_prot(pfn, PAGE_KERNEL);