linux-kernel - [PATCH 01/12] percpu: update free path with correct new free region

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Date:   Wed, 27 Feb 2019 21:18:28 -0500
From:   Dennis Zhou <dennis@...nel.org>
To:     Dennis Zhou <dennis@...nel.org>, Tejun Heo <tj@...nel.org>,
        Christoph Lameter <cl@...ux.com>
Cc:     Vlad Buslov <vladbu@...lanox.com>, kernel-team@...com,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: [PATCH 01/12] percpu: update free path with correct new free region

When updating the chunk's contig_hint on the free path of a hint that
does not touch the page boundaries, it was incorrectly using the
starting offset of the free region and the block's contig_hint. This
could lead to incorrect assumptions about fit given a size and better
alignment of the start. Fix this by using (end - start) as this is only
called when updating a hint within a block.

Signed-off-by: Dennis Zhou <dennis@...nel.org>
---
 mm/percpu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/percpu.c b/mm/percpu.c
index db86282fd024..53bd79a617b1 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -871,7 +871,7 @@ static void pcpu_block_update_hint_free(struct pcpu_chunk *chunk, int bit_off,
 		pcpu_chunk_refresh_hint(chunk);
 	else
 		pcpu_chunk_update(chunk, pcpu_block_off_to_off(s_index, start),
-				  s_block->contig_hint);
+				  end - start);
 }

 /**
-- 
2.17.1