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| author | Aneesh Kumar K.V | 2014-03-15 11:47:58 +0100 |
|---|---|---|
| committer | Benjamin Herrenschmidt | 2014-03-23 23:48:34 +0100 |
| commit | 346519a1606e196bd5f11b9f5eacaf60f70477a1 (patch) | |
| tree | 97b5861188bb1dd0cdb79efcd0866228aa75fb2f | |
| parent | powerpc: Rate-limit users spamming kernel log buffer (diff) | |
| download | kernel-qcow2-linux-346519a1606e196bd5f11b9f5eacaf60f70477a1.tar.gz kernel-qcow2-linux-346519a1606e196bd5f11b9f5eacaf60f70477a1.tar.xz kernel-qcow2-linux-346519a1606e196bd5f11b9f5eacaf60f70477a1.zip | |
powerpc/mm: Make sure a local_irq_disable prevent a parallel THP split
We have generic code like the one in get_futex_key that assume that
a local_irq_disable prevents a parallel THP split. Support that by
adding a dummy smp call function after setting _PAGE_SPLITTING. Code
paths like get_user_pages_fast still need to check for _PAGE_SPLITTING
after disabling IRQ which indicate that a parallel THP splitting is
ongoing. Now if they don't find _PAGE_SPLITTING set, then we can be
sure that parallel split will now block in pmdp_splitting flush
until we enables IRQ
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
| -rw-r--r-- | arch/powerpc/mm/pgtable_64.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c index 62bf5e8e78da..f6ce1f111f5b 100644 --- a/arch/powerpc/mm/pgtable_64.c +++ b/arch/powerpc/mm/pgtable_64.c @@ -647,6 +647,11 @@ void pmdp_splitting_flush(struct vm_area_struct *vma, if (old & _PAGE_HASHPTE) hpte_do_hugepage_flush(vma->vm_mm, address, pmdp); } + /* + * This ensures that generic code that rely on IRQ disabling + * to prevent a parallel THP split work as expected. + */ + kick_all_cpus_sync(); } /* |