The patch titled Subject: mm/swapfile.c: put_swap_page: share more between huge/normal code path has been added to the -mm tree. Its filename is swap-put_swap_page-share-more-between-huge-normal-code-path.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/swap-put_swap_page-share-more-between-huge-normal-code-path.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/swap-put_swap_page-share-more-between-huge-normal-code-path.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Huang Ying <ying.huang@xxxxxxxxx> Subject: mm/swapfile.c: put_swap_page: share more between huge/normal code path In this patch, locking related code is shared between huge/normal code path in put_swap_page() to reduce code duplication. And `free_entries == 0` case is merged into more general `free_entries != SWAPFILE_CLUSTER` case, because the new locking method makes it easy. The added lines is same as the removed lines. But the code size is increased when CONFIG_TRANSPARENT_HUGEPAGE=n. text data bss dec hex filename base: 24123 2004 340 26467 6763 mm/swapfile.o unified: 24485 2004 340 26829 68cd mm/swapfile.o Dig on step deeper with `size -A mm/swapfile.o` for base and unified kernel and compare the result, yields, -.text 17723 0 +.text 17835 0 -.orc_unwind_ip 1380 0 +.orc_unwind_ip 1480 0 -.orc_unwind 2070 0 +.orc_unwind 2220 0 -Total 26686 +Total 27048 The total difference is the same. The text segment difference is much smaller: 112. More difference comes from the ORC unwinder segments: (1480 + 2220) - (1380 + 2070) = 250. If the frame pointer unwinder is used, this costs nothing. Link: http://lkml.kernel.org/r/20180720071845.17920-9-ying.huang@xxxxxxxxx Signed-off-by: "Huang, Ying" <ying.huang@xxxxxxxxx> Reviewed-by: Daniel Jordan <daniel.m.jordan@xxxxxxxxxx> Acked-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Shaohua Li <shli@xxxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Minchan Kim <minchan@xxxxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/swapfile.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff -puN mm/swapfile.c~swap-put_swap_page-share-more-between-huge-normal-code-path mm/swapfile.c --- a/mm/swapfile.c~swap-put_swap_page-share-more-between-huge-normal-code-path +++ a/mm/swapfile.c @@ -1223,8 +1223,8 @@ void put_swap_page(struct page *page, sw if (!si) return; + ci = lock_cluster_or_swap_info(si, offset); if (size == SWAPFILE_CLUSTER) { - ci = lock_cluster(si, offset); VM_BUG_ON(!cluster_is_huge(ci)); map = si->swap_map + offset; for (i = 0; i < SWAPFILE_CLUSTER; i++) { @@ -1233,13 +1233,9 @@ void put_swap_page(struct page *page, sw if (val == SWAP_HAS_CACHE) free_entries++; } - if (!free_entries) { - for (i = 0; i < SWAPFILE_CLUSTER; i++) - map[i] &= ~SWAP_HAS_CACHE; - } cluster_clear_huge(ci); - unlock_cluster(ci); if (free_entries == SWAPFILE_CLUSTER) { + unlock_cluster_or_swap_info(si, ci); spin_lock(&si->lock); ci = lock_cluster(si, offset); memset(map, 0, SWAPFILE_CLUSTER); @@ -1250,12 +1246,16 @@ void put_swap_page(struct page *page, sw return; } } - if (size == 1 || free_entries) { - for (i = 0; i < size; i++, entry.val++) { - if (!__swap_entry_free(si, entry, SWAP_HAS_CACHE)) - free_swap_slot(entry); + for (i = 0; i < size; i++, entry.val++) { + if (!__swap_entry_free_locked(si, offset + i, SWAP_HAS_CACHE)) { + unlock_cluster_or_swap_info(si, ci); + free_swap_slot(entry); + if (i == size - 1) + return; + lock_cluster_or_swap_info(si, offset); } } + unlock_cluster_or_swap_info(si, ci); } #ifdef CONFIG_THP_SWAP _ Patches currently in -mm which might be from ying.huang@xxxxxxxxx are mm-clear_huge_page-move-order-algorithm-into-a-separate-function.patch mm-huge-page-copy-target-sub-page-last-when-copy-huge-page.patch mm-hugetlbfs-rename-address-to-haddr-in-hugetlb_cow.patch mm-hugetlbfs-pass-fault-address-to-cow-handler.patch mm-swap-make-config_thp_swap-depends-on-config_swap.patch swap-add-comments-to-lock_cluster_or_swap_info.patch mm-swapfilec-replace-some-ifdef-with-is_enabled.patch swap-use-swap_count-in-swap_page_trans_huge_swapped.patch swap-unify-normal-huge-code-path-in-swap_page_trans_huge_swapped.patch swap-unify-normal-huge-code-path-in-put_swap_page.patch swap-get_swap_pages-use-entry_size-instead-of-cluster-in-parameter.patch swap-add-__swap_entry_free_locked.patch swap-put_swap_page-share-more-between-huge-normal-code-path.patch mm-swap-fix-race-between-swapoff-and-some-swap-operations.patch mm-swap-fix-race-between-swapoff-and-some-swap-operations-v6.patch mm-fix-race-between-swapoff-and-mincore.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html