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SubjectRe: [PATCH 2.4.0-test8] mm/filemap.c
Also sprach David Mansfield:
} Bill Wendling wrote:
} >
} > Hi Linus,
} >
} > Here's a small optimization for the mm/filemap.c file.
} >
} > - The `head = &mapping->pages;' statement is useless inside the
} > repeat, since head isn't modified inside the loop.
} > - The `curr = curr->next;' statement doesn't need to be executed
} > if the repeat is taken. I changed the while() into a for() loop
} > to accomodate this better.
} >
} I spotted the curr = curr->next thing yesterday, too! I think you're
} right on that one. But I'm not sure about the head = &mapping thing.
} The reason we jump back here is that we've been outside the spinlock'ed
} critical section. Is it possible for the &mapping->pages to change
} during this period of time (when spinlock isn't held?), if not, your
} patch is ok. If it could change, we need to re-initialize head because
} it could have changed while we didn't have the lock locked.
Doh...Yeah. But...Shouldn't the `head = &mapping->pages;' thing be inside
of a spinlock if &mapping->pages could change? Say it changed between the
assignment and the function grabbing the lock?

Does anyone else know better on this?

|| Bill Wendling
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