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SubjectRe: [PATCH RFC] vmalloc: eagerly clear ptes on vunmap
On Mon, 29 Nov 2010 12:32:11 -0800
Jeremy Fitzhardinge <jeremy@goop.org> wrote:

> When unmapping a region in the vmalloc space, clear the ptes immediately.
> There's no point in deferring this because there's no amortization
> benefit.
>
> The TLBs are left dirty, and they are flushed lazily to amortize the
> cost of the IPIs.
>
> This specific motivation for this patch is a regression since 2.6.36 when
> using NFS under Xen, triggered by the NFS client's use of vm_map_ram()
> introduced in 56e4ebf877b6043c289bda32a5a7385b80c17dee. XFS also uses
> vm_map_ram() and could cause similar problems.
>

Do we have any quantitative info on that regression? The patch fixed
it, I assume?



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