Change Details

This is based on the observation by Yoshihiro Ota expressed in D22256, but exploits that observation differently. Break swap_pager_meta_ctl into two functions, swap_pager_meta_lookup and swap_pager_meta_remove. Use one or the other in place of swap_pager_meta_ctl depending on whether the POP flag bit was set by the caller. For the instance of swap_pager_meta_remove left in swap_pager_copy, replace it with an implementation that copies from vm_pager_meta_free_all to find the next nonempty source swap block, rather than testing every source swap block for emptiness.

This is based on the observation by Yoshihiro Ota expressed in D22256, but exploits that observation differently. Modify swp_pager_meta_free to create swp_pager_meta_copy_free that can implement swp_pager_meta_free and also do the "Transfer source to destination" work of swap_pager_copy. The benefit of this change is fewer pctrie accesses and more efficient freeing of trie elements in swap_pager_copy.

This is based on the observation by Yoshihiro Ota expressed in D22256, but exploits that observation differently. Break swap_pager_meta_ctl into two functions, swap_pager_meta_lookup and swap_pager_meta_removeModify swp_pager_meta_free to create swp_pager_meta_copy_free that can implement swp_pager_meta_free and also do the "Transfer source to destination" work of swap_pager_copy. Use one or the other in place of swap_pager_meta_ctl depending on whether the POP flag bit was set by the caller. For the instance of swap_pager_meta_remove left in swap_pager_copy, replace it with an implementation that copies from vm_pager_meta_free_all to find the next nonempty source swap block, rather than testing every source swap block for emptinessThe benefit of this change is fewer pctrie accesses and more efficient freeing of trie elements in swap_pager_copy.