Messages in this thread | | | From | "Marciniszyn, Mike" <> | Subject | RE: [PATCH 23/26] ib: Convert qib_get_user_pages() to get_user_pages_unlocked() | Date | Fri, 4 Oct 2013 13:52:49 +0000 |
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> Convert qib_get_user_pages() to use get_user_pages_unlocked(). This > shortens the section where we hold mmap_sem for writing and also removes > the knowledge about get_user_pages() locking from ipath driver. We also fix > a bug in testing pinned number of pages when changing the code. >
This patch and the sibling ipath patch will nominally take the mmap_sem twice where the old routine only took it once. This is a performance issue.
Is the intent here to deprecate get_user_pages()?
I agree, the old code's lock limit test is broke and needs to be fixed. I like the elimination of the silly wrapper routine!
Could the lock limit test be pushed into another version of the wrapper so that there is only one set of mmap_sem transactions?
Mike
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