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From: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
To: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org
Cc: Tejun Heo <tj@kernel.org>, Jens Axboe <axboe@kernel.dk>,
	Johannes Weiner <hannes@cmpxchg.org>
Subject: [PATCH 2/2] mm/filemap: rewrite mapping_needs_writeback in less fancy manner
Date: Mon, 22 Jul 2019 12:36:10 +0300	[thread overview]
Message-ID: <156378817069.1087.1302816672037672488.stgit@buzz> (raw)
In-Reply-To: <156378816804.1087.8607636317907921438.stgit@buzz>

This actually checks that writeback is needed or in progress.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
---
 mm/filemap.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index d9572593e5c7..29f503ffd70b 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -618,10 +618,13 @@ int filemap_fdatawait_keep_errors(struct address_space *mapping)
 }
 EXPORT_SYMBOL(filemap_fdatawait_keep_errors);
 
+/* Returns true if writeback might be needed or already in progress. */
 static bool mapping_needs_writeback(struct address_space *mapping)
 {
-	return (!dax_mapping(mapping) && mapping->nrpages) ||
-	    (dax_mapping(mapping) && mapping->nrexceptional);
+	if (dax_mapping(mapping))
+		return mapping->nrexceptional;
+
+	return mapping->nrpages;
 }
 
 int filemap_write_and_wait(struct address_space *mapping)


  reply	other threads:[~2019-07-22  9:36 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-22  9:36 [PATCH 1/2] mm/filemap: don't initiate writeback if mapping has no dirty pages Konstantin Khlebnikov
2019-07-22  9:36 ` Konstantin Khlebnikov [this message]
2019-07-23  0:52 ` Andrew Morton
2019-07-23  8:16   ` Konstantin Khlebnikov
2019-07-30 14:14     ` Jan Kara
2019-07-30 14:57       ` Konstantin Khlebnikov
2019-07-30 15:48         ` Jan Kara
2019-07-30 18:15           ` Konstantin Khlebnikov

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