Re: [PATCH 5/5] Swapless V2: Revise main migration logic

From: Christoph Lameter
Date: Mon Apr 17 2006 - 21:58:47 EST


On Tue, 18 Apr 2006, KAMEZAWA Hiroyuki wrote:

> BTW, when copying mm, mm->mmap_sem is held. Is mm->mmap_sem is not held while
> page migraion now ? I'm sorry I can't catch up all changes.
> or Is this needed for lazy migration (migration-on-fault) ?

mmap_sem must be held during page migration due to the way we retrieve the
anonymous vma.

I think you would want to get rid of that requirement for the hotplug
remove. But how do we reliably get to the anon_vma of the page without
mmap_sem?

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