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
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------------------------------------------------------
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
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