Messages in this thread |  | | Date | Wed, 4 Jun 2003 15:37:59 -0700 | From | William Lee Irwin III <> | Subject | Re: [PATCH] Remove page_table_lock from vma manipulations |
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On Wed, Jun 04, 2003 at 05:30:25PM -0500, Dave McCracken wrote: > After more careful consideration, I don't see any reasons why > page_table_lock is necessary for dealing with vmas. I found one spot in > swapoff, but it was easily changed to mmap_sem. I've beat on this code and > mjb has beat on this code with no problems. Here's the patch to remove it. > Feel free to poke holes in it.
shrink_list() calls try_to_unmap() under pte_chain_lock(page), and hence try_to_unmap() cannot sleep. Furthermore try_to_unmap() calls find_vma() under the sole protection of spin_trylock(&mm->page_table_lock), which I don't see changed to a read_trylock(&mm->mmap_sem) here.
Hence, this is racy.
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