Messages in this thread | ![/](/images/icornerl.gif) | | Date | Thu, 10 Dec 2015 13:24:38 -0700 | From | Ross Zwisler <> | Subject | Re: [PATCH v3 3/7] mm: add find_get_entries_tag() |
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On Wed, Dec 09, 2015 at 11:44:16AM -0800, Dan Williams wrote: > On Tue, Dec 8, 2015 at 11:18 AM, Ross Zwisler > <ross.zwisler@linux.intel.com> wrote: > > Add find_get_entries_tag() to the family of functions that include > > find_get_entries(), find_get_pages() and find_get_pages_tag(). This is > > needed for DAX dirty page handling because we need a list of both page > > offsets and radix tree entries ('indices' and 'entries' in this function) > > that are marked with the PAGECACHE_TAG_TOWRITE tag. > > > > Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> <> > Why does this mostly duplicate find_get_entries()? > > Surely find_get_entries() can be implemented as a special case of > find_get_entries_tag().
I'm adding find_get_entries_tag() to the family of functions that already exist and include find_get_entries(), find_get_pages(), find_get_pages_contig() and find_get_pages_tag().
These functions all contain very similar code with small changes to the internal looping based on whether you're looking through all radix slots or only the ones that match a certain tag (radix_tree_for_each_slot() vs radix_tree_for_each_tagged()).
We already have find_get_page() to get all pages in a range and find_get_pages_tag() to get all pages in the range with a certain tag. We have find_get_entries() to get all pages and indices for a given range, but we are currently missing find_get_entries_tag() to do that same search based on a tag, which is what I'm adding.
I agree that we could probably figure out a way to combine the code for find_get_entries() with find_get_entries_tag(), as we could do for the existing functions find_get_pages() and find_get_pages_tag(). I think we should probably add find_get_entries_tag() per this patch, though, and then decide whether to do any combining later as a separate step.
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