Messages in this thread | | | Date | Wed, 30 Aug 2023 15:26:11 +0800 | Subject | Re: [PATCH 09/12] hugetlb_vmemmap: Optimistically set Optimized flag | From | Muchun Song <> |
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On 2023/8/26 03:04, Mike Kravetz wrote: > At the beginning of hugetlb_vmemmap_optimize, optimistically set > the HPageVmemmapOptimized flag in the head page. Clear the flag > if the operation fails. > > No change in behavior. However, this will become important in > subsequent patches where we batch delay TLB flushing. We need to > make sure the content in the old and new vmemmap pages are the same.
Sorry, I didn't get the point here. Could you elaborate it?
> > Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> > --- > mm/hugetlb_vmemmap.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c > index e390170c0887..500a118915ff 100644 > --- a/mm/hugetlb_vmemmap.c > +++ b/mm/hugetlb_vmemmap.c > @@ -566,7 +566,9 @@ static void __hugetlb_vmemmap_optimize(const struct hstate *h, > if (!vmemmap_should_optimize(h, head)) > return; > > + /* Optimistically assume success */ > static_branch_inc(&hugetlb_optimize_vmemmap_key); > + SetHPageVmemmapOptimized(head); > > vmemmap_end = vmemmap_start + hugetlb_vmemmap_size(h); > vmemmap_reuse = vmemmap_start; > @@ -577,10 +579,10 @@ static void __hugetlb_vmemmap_optimize(const struct hstate *h, > * to the page which @vmemmap_reuse is mapped to, then free the pages > * which the range [@vmemmap_start, @vmemmap_end] is mapped to. > */ > - if (vmemmap_remap_free(vmemmap_start, vmemmap_end, vmemmap_reuse, bulk_pages)) > + if (vmemmap_remap_free(vmemmap_start, vmemmap_end, vmemmap_reuse, bulk_pages)) { > static_branch_dec(&hugetlb_optimize_vmemmap_key); > - else > - SetHPageVmemmapOptimized(head); > + ClearHPageVmemmapOptimized(head); > + } > } > > /**
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