On Tue, May 07, 2013 at 02:19:55PM -0700, Dave Hansen wrote: > > From: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> > > There are only two callers of swapcache_free() which actually > pass in a non-NULL 'struct page'. Both of them > (__remove_mapping and delete_from_swap_cache()) create a > temporary on-stack 'swp_entry_t' and set entry.val to > page_private(). > > They need to do this since __delete_from_swap_cache() does > set_page_private(page, 0) and destroys the information. > > However, I'd like to batch a few of these operations on several > pages together in a new version of __remove_mapping(), and I > would prefer not to have to allocate temporary storage for > each page. The code is pretty ugly, and it's a bit silly > to create these on-stack 'swp_entry_t's when it is so easy to > just keep the information around in 'struct page'. > > There should not be any danger in doing this since we are > absolutely on the path of freeing these page. There is no > turning back, and no other rerferences can be obtained > after it comes out of the radix tree. > > Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> On it's own, this patch looks like it has a lot missing but when combined with patch 2, it starts making sense so Acked-by: Mel Gorman <mgorman@xxxxxxx> -- Mel Gorman SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>