mm/thp: use head for head page in lru_add_page_tail()

Since the first parameter is only used by head page, it's better to make
it explicit.

Link: https://lkml.kernel.org/r/1604566549-62481-3-git-send-email-alex.shi@linux.alibaba.com
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Alexander Duyck <alexander.duyck@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: "Chen, Rong A" <rong.a.chen@intel.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Jann Horn <jannh@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mika Penttilä <mika.penttila@nextfour.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 85b50ba..f33a614 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2359,33 +2359,32 @@ static void remap_page(struct page *page, unsigned int nr)
        }
 }
 
-static void lru_add_page_tail(struct page *page, struct page *page_tail,
+static void lru_add_page_tail(struct page *head, struct page *tail,
                struct lruvec *lruvec, struct list_head *list)
 {
-       VM_BUG_ON_PAGE(!PageHead(page), page);
-       VM_BUG_ON_PAGE(PageCompound(page_tail), page);
-       VM_BUG_ON_PAGE(PageLRU(page_tail), page);
+       VM_BUG_ON_PAGE(!PageHead(head), head);
+       VM_BUG_ON_PAGE(PageCompound(tail), head);
+       VM_BUG_ON_PAGE(PageLRU(tail), head);
        lockdep_assert_held(&lruvec_pgdat(lruvec)->lru_lock);
 
        if (!list)
-               SetPageLRU(page_tail);
+               SetPageLRU(tail);
 
-       if (likely(PageLRU(page)))
-               list_add_tail(&page_tail->lru, &page->lru);
+       if (likely(PageLRU(head)))
+               list_add_tail(&tail->lru, &head->lru);
        else if (list) {
                /* page reclaim is reclaiming a huge page */
-               get_page(page_tail);
-               list_add_tail(&page_tail->lru, list);
+               get_page(tail);
+               list_add_tail(&tail->lru, list);
        } else {
                /*
                 * Head page has not yet been counted, as an hpage,
                 * so we must account for each subpage individually.
                 *
-                * Put page_tail on the list at the correct position
+                * Put tail on the list at the correct position
                 * so they all end up in order.
                 */
-               add_page_to_lru_list_tail(page_tail, lruvec,
-                                         page_lru(page_tail));
+               add_page_to_lru_list_tail(tail, lruvec, page_lru(tail));
        }
 }