Christoph Hellwig 9f87fc4d72 block: queue data commands from the flush state machine at the head
We used to insert the data commands following a pre-flush to the head
of the queue until commit 1e82fadfc6 ("blk-mq: do not do head insertions
post-pre-flush commands").  Not doing this seems to cause hangs of
such commands on NFS workloads when exported from file systems with
SATA SSDs.  I have no idea why this would starve these workloads,
but doing a semantic revert of this patch (which looks quite different
due to various other changes) fixes the hangs.

Fixes: 1e82fadfc6 ("blk-mq: do not do head insertions post-pre-flush commands")
Reported-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Chuck Lever <chuck.lever@oracle.com>
Link: https://lore.kernel.org/r/20230714143014.11879-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-14 08:42:58 -06:00
2022-09-28 09:02:20 +02:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
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    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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