Messages in this thread | | | Date | Thu, 23 Jun 2022 09:44:20 +0200 | From | Joerg Roedel <> | Subject | Re: [PATCH] iommu/amd: Use try_cmpxchg64 in alloc_pte and free_clear_pte |
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On Wed, May 25, 2022 at 04:54:16PM +0200, Uros Bizjak wrote: > Use try_cmpxchg64 instead of cmpxchg64 (*ptr, old, new) != old in > alloc_pte and free_clear_pte. cmpxchg returns success in ZF flag, so this > change saves a compare after cmpxchg (and related move instruction > in front of cmpxchg). Also, remove racy explicit assignment to pteval > when cmpxchg fails, this is what try_cmpxchg does implicitly from > *pte in an atomic way. > > Signed-off-by: Uros Bizjak <ubizjak@gmail.com> > Cc: Joerg Roedel <joro@8bytes.org> > Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> > Cc: Will Deacon <will@kernel.org> > --- > drivers/iommu/amd/io_pgtable.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-)
Applied, thanks.
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