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| author |   Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> | 2020-05-05 12:47:27 +0530 |
|---|---|---|
| committer |   Michael Ellerman <mpe@ellerman.id.au> | 2020-05-05 21:20:16 +1000 |
| commit | e21dfbf01346ee4447d1533b1c57a003c773c6e3 (patch) | |
| tree | fc8f6c398cac75fe9549985f7424162e7d145d1e /arch/powerpc/mm/book3s64/pgtable.c | |
| parent | powerpc/kvm/book3s: Use pte_present instead of opencoding _PAGE_PRESENT check (diff) | |
| download | linux-dev-e21dfbf01346ee4447d1533b1c57a003c773c6e3.tar.xz linux-dev-e21dfbf01346ee4447d1533b1c57a003c773c6e3.zip | |
powerpc/mm/book3s64: Avoid sending IPI on clearing PMD
Now that all the lockless page table walk is careful w.r.t the PTE
address returned, we can now revert
commit: 13bd817bb884 ("powerpc/thp: Serialize pmd clear against a linux page table walk.")
We also drop the equivalent IPI from other pte updates routines. We still keep
IPI in hash pmdp collapse and that is to take care of parallel hash page table
insert. The radix pmdp collapse flush can possibly be removed once I am sure
generic code doesn't have the any expectations around parallel gup walk.
This speeds up Qemu guest RAM del/unplug time as below
128 core, 496GB guest:
Without patch:
munmap start: timer = 13162 ms, PID=7684
munmap finish: timer = 95312 ms, PID=7684 - delta = 82150 ms
With patch:
munmap start: timer = 196449 ms, PID=6681
munmap finish: timer = 196488 ms, PID=6681 - delta = 39ms
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200505071729.54912-21-aneesh.kumar@linux.ibm.com
Diffstat (limited to 'arch/powerpc/mm/book3s64/pgtable.c')
| -rw-r--r-- | arch/powerpc/mm/book3s64/pgtable.c | 8 |
1 files changed, 0 insertions, 8 deletions
diff --git a/arch/powerpc/mm/book3s64/pgtable.c b/arch/powerpc/mm/book3s64/pgtable.c index e0bb69c616e4..127325ead505 100644 --- a/arch/powerpc/mm/book3s64/pgtable.c +++ b/arch/powerpc/mm/book3s64/pgtable.c @@ -109,14 +109,6 @@ pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address, old_pmd = pmd_hugepage_update(vma->vm_mm, address, pmdp, _PAGE_PRESENT, _PAGE_INVALID); flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE); - /* - * This ensures that generic code that rely on IRQ disabling - * to prevent a parallel THP split work as expected. - * - * Marking the entry with _PAGE_INVALID && ~_PAGE_PRESENT requires - * a special case check in pmd_access_permitted. - */ - serialize_against_pte_lookup(vma->vm_mm); return __pmd(old_pmd); } |