Messages in this thread | | | Subject | Re: [RFC PATCH 2/2] mm: Batch page_check_references in shrink_page_list sharing the same i_mmap_mutex | From | Tim Chen <> | Date | Tue, 21 Aug 2012 15:53:01 -0700 |
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On Tue, 2012-08-21 at 09:21 -0400, Matthew Wilcox wrote:
> > The only clunky bit would seem to be this bit: > > > if (page_mapped(page) && mapping) { > > - switch (try_to_unmap(page, TTU_UNMAP)) { > > + switch (try_to_unmap(page, TTU_UNMAP, > > + mmap_mutex_locked)) { > > Which I think has to look like this: > > if (page_mapped(page) && mapping) { > - switch (try_to_unmap(page, TTU_UNMAP)) { > + int result; > + if (i_mmap_mutex) > + result = __try_to_unmap(page, TTU_UNMAP); > + else > + result = try_to_unmap(page, TTU_UNMAP); > + switch (result) { >
I think
- switch (try_to_unmap(page, TTU_UNMAP)) { + switch (__try_to_unmap(page, TTU_UNMAP)) {
should be enough when your changes are adopted. Because if the page mmap mutex needs to be locked, we will have locked it here before __try_to_unmap gets used.
+ if (needs_page_mmap_mutex(page) && + i_mmap_mutex != &page->mapping->i_mmap_mutex) { + if (i_mmap_mutex) + mutex_unlock(i_mmap_mutex); + i_mmap_mutex = &page->mapping->i_mmap_mutex; + mutex_lock(i_mmap_mutex); + }
Tim
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