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4c9f948142
nfs and cifs on Linux currently have a mount parameter "actimeo" to control metadata (attribute) caching but cifs does not have additional mount parameters to allow distinguishing between caching directory metadata (e.g. needed to revalidate paths) and that for files. Add new mount parameter "acdirmax" to allow caching metadata for directories more loosely than file data. NFS adjusts metadata caching from acdirmin to acdirmax (and another two mount parms for files) but to reduce complexity, it is safer to just introduce the one mount parm to allow caching directories longer. The defaults for acdirmax and actimeo (for cifs.ko) are conservative, 1 second (NFS defaults acdirmax to 60 seconds). For many workloads, setting acdirmax to a higher value is safe and will improve performance. This patch leaves unchanged the default values for caching metadata for files and directories but gives the user more flexibility in adjusting them safely for their workload via the new mount parm. Signed-off-by: Steve French <stfrench@microsoft.com> Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com> Reviewed-By: Tom Talpey <tom@talpey.com>
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
``make pdfdocs``. The formatted documentation can also be read online at:
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.