Messages in this thread |  | | Date | Sat, 29 Apr 2017 16:18:38 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH v2] mm, zone_device: replace {get, put}_zone_device_page() with a single reference |
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* Dan Williams <dan.j.williams@intel.com> wrote:
> Kirill points out that the calls to {get,put}_dev_pagemap() can be > removed from the mm fast path if we take a single get_dev_pagemap() > reference to signify that the page is alive and use the final put of the > page to drop that reference. > > This does require some care to make sure that any waits for the > percpu_ref to drop to zero occur *after* devm_memremap_page_release(), > since it now maintains its own elevated reference. > > Cc: Ingo Molnar <mingo@redhat.com> > Cc: Jérôme Glisse <jglisse@redhat.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Reviewed-by: Logan Gunthorpe <logang@deltatee.com> > Suggested-by: Kirill Shutemov <kirill.shutemov@linux.intel.com> > Tested-by: Kirill Shutemov <kirill.shutemov@linux.intel.com> > Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This changelog is lacking an explanation about how this solves the crashes you were seeing.
Thanks,
Ingo
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