From: Jan Kara <jack@suse.cz>
To: Shaohua Li <shli@kernel.org>
Cc: Jan Kara <jack@suse.cz>,
linux-raid@vger.kernel.org, Mike Snitzer <snitzer@redhat.com>,
dm-devel@redhat.com
Subject: [PATCH 0/2 v2] Fix fallout from changes to FUA and PREFLUSH definitions
Date: Wed, 31 May 2017 09:44:31 +0200 [thread overview]
Message-ID: <20170531074433.14298-1-jack@suse.cz> (raw)
Hello,
here are patches for DM/MD that address a possible performance issue caused by
commit b685d3d65ac7 "block: treat REQ_FUA and REQ_PREFLUSH as synchronous".
The core of the problem is that above mentioned commit removed REQ_SYNC flag
from WRITE_{FUA|PREFLUSH|...} definitions. generic_make_request_checks()
however strips REQ_FUA and REQ_PREFLUSH flags from a bio when the storage
doesn't report volatile write cache and thus write effectively becomes
asynchronous which can lead to performance regressions.
DM/MD guys, can you please have a look at patches and take them through your
trees? Thanks!
Honza
next reply other threads:[~2017-05-31 7:44 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-31 7:44 Jan Kara [this message]
2017-05-31 7:44 ` [PATCH 2/2] md: Make flush bios explicitely sync Jan Kara
2017-05-31 16:23 ` Shaohua Li
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