+ mm-zbud-reuse-unbuddied-as-buddied-in-zbud_pool.patch added to -mm tree

+ mm-zbud-reuse-unbuddied-as-buddied-in-zbud_pool.patch added to -mm tree

[akpm]

The patch titled
     Subject: mm/zbud: reuse unbuddied[0] as buddied in zbud_pool
has been added to the -mm tree.  Its filename is
     mm-zbud-reuse-unbuddied-as-buddied-in-zbud_pool.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-zbud-reuse-unbuddied-as-buddied-in-zbud_pool.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-zbud-reuse-unbuddied-as-buddied-in-zbud_pool.patch

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------------------------------------------------------
From: Miaohe Lin <linmiaohe@huawei.com>
Subject: mm/zbud: reuse unbuddied[0] as buddied in zbud_pool

Patch series "Cleanups for zbud", v2.

This series contains just cleanups to save some possible memory in
zbud_pool and avoid exporting any unneeded zbud API.  More details can be
found in the respective changelogs


This patch (of 2):

Since commit 9d8c5b5284e4 ("mm: zbud: fix condition check on allocation
size"), zbud_pool.unbuddied[0] is always unused.  We can reuse it as
buddied field to save some possible memory.

Link: https://lkml.kernel.org/r/20210608114515.206992-1-linmiaohe@huawei.com
Link: https://lkml.kernel.org/r/20210608114515.206992-2-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/zbud.c |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

--- a/mm/zbud.c~mm-zbud-reuse-unbuddied-as-buddied-in-zbud_pool
+++ a/mm/zbud.c
@@ -93,8 +93,14 @@
  */
 struct zbud_pool {
 	spinlock_t lock;
-	struct list_head unbuddied[NCHUNKS];
-	struct list_head buddied;
+	union {
+		/*
+		 * Reuse unbuddied[0] as buddied on the ground that
+		 * unbuddied[0] is unused.
+		 */
+		struct list_head buddied;
+		struct list_head unbuddied[NCHUNKS];
+	};
 	struct list_head lru;
 	u64 pages_nr;
 	const struct zbud_ops *ops;
_

Patches currently in -mm which might be from linmiaohe@huawei.com are

mm-swapfile-use-percpu_ref-to-serialize-against-concurrent-swapoff.patch
swap-fix-do_swap_page-race-with-swapoff.patch
mm-swap-remove-confusing-checking-for-non_swap_entry-in-swap_ra_info.patch
mm-shmem-fix-shmem_swapin-race-with-swapoff.patch
mm-swapfile-move-get_swap_page_of_type-under-config_hibernation.patch
mm-swapfile-move-get_swap_page_of_type-under-config_hibernation-fix.patch
mm-swapfile-move-get_swap_page_of_type-under-config_hibernation-fix-2.patch
mm-swap-remove-unused-local-variable-nr_shadows.patch
mm-swap_slotsc-delete-meaningless-forward-declarations.patch
mm-swap-remove-unused-global-variable-nr_swapper_spaces.patch
mm-huge_memoryc-remove-dedicated-macro-hpage_cache_index_mask.patch
mm-huge_memoryc-use-page-deferred_list.patch
mm-huge_memoryc-add-missing-read-only-thp-checking-in-transparent_hugepage_enabled.patch
mm-huge_memoryc-add-missing-read-only-thp-checking-in-transparent_hugepage_enabled-v4.patch
mm-huge_memoryc-remove-unnecessary-tlb_remove_page_size-for-huge-zero-pmd.patch
mm-huge_memoryc-dont-discard-hugepage-if-other-processes-are-mapping-it.patch
mm-zbud-reuse-unbuddied-as-buddied-in-zbud_pool.patch
mm-zbud-dont-export-any-zbud-api.patch
mm-zswapc-remove-unused-function-zswap_debugfs_exit.patch
mm-zswapc-avoid-unnecessary-copy-in-at-map-time.patch
mm-zswapc-fix-two-bugs-in-zswap_writeback_entry.patch