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From:   Alex Shi <alex.shi@linux.alibaba.com>
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Subject: [PATCH v17 03/21] mm/compaction: correct the comments of compact_defer_shift
Date:   Sat, 25 Jul 2020 20:59:40 +0800
Message-Id: <1595681998-19193-4-git-send-email-alex.shi@linux.alibaba.com>
In-Reply-To: <1595681998-19193-1-git-send-email-alex.shi@linux.alibaba.com>
References: <1595681998-19193-1-git-send-email-alex.shi@linux.alibaba.com>
Sender: linux-kernel-owner@vger.kernel.org
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There is no compact_defer_limit. It should be compact_defer_shift in
use. and add compact_order_failed explanation.

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
---
 include/linux/mmzone.h | 1 +
 mm/compaction.c        | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index f6f884970511..14c668b7e793 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -512,6 +512,7 @@ struct zone {
 	 * On compaction failure, 1<<compact_defer_shift compactions
 	 * are skipped before trying again. The number attempted since
 	 * last failure is tracked with compact_considered.
+	 * compact_order_failed is the minimum compaction failed order.
 	 */
 	unsigned int		compact_considered;
 	unsigned int		compact_defer_shift;
diff --git a/mm/compaction.c b/mm/compaction.c
index 86375605faa9..cd1ef9e5e638 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -136,7 +136,7 @@ void __ClearPageMovable(struct page *page)
 
 /*
  * Compaction is deferred when compaction fails to result in a page
- * allocation success. 1 << compact_defer_limit compactions are skipped up
+ * allocation success. compact_defer_shift++, compactions are skipped up
  * to a limit of 1 << COMPACT_MAX_DEFER_SHIFT
  */
 void defer_compaction(struct zone *zone, int order)
-- 
1.8.3.1