On Fri, Oct 12, 2018 at 01:24:22PM -0400, Andrea Arcangeli wrote: > Hello, > > On Fri, Oct 12, 2018 at 12:20:54PM -0400, Zi Yan wrote: > > On 12 Oct 2018, at 12:09, jgli...@redhat.com wrote: > > > > > From: Jérôme Glisse <jgli...@redhat.com> > > > > > > Inside set_pmd_migration_entry() we are holding page table locks and > > > thus we can not sleep so we can not call invalidate_range_start/end() > > > > > > So remove call to mmu_notifier_invalidate_range_start/end() and add > > > call to mmu_notifier_invalidate_range(). Note that we are already > > Why the call to mmu_notifier_invalidate_range if we're under > range_start and followed by range_end? (it's not _range_only_end, if > it was _range_only_end the above would be needed)
I wanted to be extra safe and accept to over invalidate. You are right that it is not strictly necessary. I am fine with removing it. > > > > calling mmu_notifier_invalidate_range_start/end() inside the function > > > calling set_pmd_migration_entry() (see try_to_unmap_one()). > > > > > > Signed-off-by: Jérôme Glisse <jgli...@redhat.com> > > > Reported-by: Andrea Arcangeli <aarca...@redhat.com> > > > Cc: Andrew Morton <a...@linux-foundation.org> > > > Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org> > > > Cc: Zi Yan <zi....@cs.rutgers.edu> > > > Cc: Kirill A. Shutemov <kirill.shute...@linux.intel.com> > > > Cc: "H. Peter Anvin" <h...@zytor.com> > > > Cc: Anshuman Khandual <khand...@linux.vnet.ibm.com> > > > Cc: Dave Hansen <dave.han...@intel.com> > > > Cc: David Nellans <dnell...@nvidia.com> > > > Cc: Ingo Molnar <mi...@elte.hu> > > > Cc: Mel Gorman <mgor...@techsingularity.net> > > > Cc: Minchan Kim <minc...@kernel.org> > > > Cc: Naoya Horiguchi <n-horigu...@ah.jp.nec.com> > > > Cc: Thomas Gleixner <t...@linutronix.de> > > > Cc: Vlastimil Babka <vba...@suse.cz> > > > Cc: Michal Hocko <mho...@kernel.org> > > > Cc: Andrea Arcangeli <aarca...@redhat.com> > > > --- > > > mm/huge_memory.c | 7 +------ > > > 1 file changed, 1 insertion(+), 6 deletions(-) > > > > > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > > > index 533f9b00147d..93cb80fe12cb 100644 > > > --- a/mm/huge_memory.c > > > +++ b/mm/huge_memory.c > > > @@ -2885,9 +2885,6 @@ void set_pmd_migration_entry(struct > > > page_vma_mapped_walk *pvmw, > > > if (!(pvmw->pmd && !pvmw->pte)) > > > return; > > > > > > - mmu_notifier_invalidate_range_start(mm, address, > > > - address + HPAGE_PMD_SIZE); > > > - > > > flush_cache_range(vma, address, address + HPAGE_PMD_SIZE); > > > pmdval = *pvmw->pmd; > > > pmdp_invalidate(vma, address, pvmw->pmd); > > > @@ -2898,11 +2895,9 @@ void set_pmd_migration_entry(struct > > > page_vma_mapped_walk *pvmw, > > > if (pmd_soft_dirty(pmdval)) > > > pmdswp = pmd_swp_mksoft_dirty(pmdswp); > > > set_pmd_at(mm, address, pvmw->pmd, pmdswp); > > > + mmu_notifier_invalidate_range(mm, address, address + HPAGE_PMD_SIZE); > > It's not obvious why it's needed, if it's needed maybe a comment can > be added. We can remove it. Should i post a v2 without it ? Cheers, Jérôme
