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nfsd: increase DRC cache limit
authorJ. Bruce Fields <bfields@redhat.com>
Wed, 20 Sep 2017 00:51:31 +0000 (20:51 -0400)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sun, 4 Aug 2019 07:33:36 +0000 (09:33 +0200)
commitdbd040b42d987f6d73192e9721b8722816d38c06
treebf848843d3c335373df76cdab54313b506665e93
parent2d9b39debdcaefac57529e3e4a8e8a8ca4419527
nfsd: increase DRC cache limit

[ Upstream commit 44d8660d3bb0a1c8363ebcb906af2343ea8e15f6 ]

An NFSv4.1+ client negotiates the size of its duplicate reply cache size
in the initial CREATE_SESSION request.  The server preallocates the
memory for the duplicate reply cache to ensure that we'll never fail to
record the response to a nonidempotent operation.

To prevent a few CREATE_SESSIONs from consuming all of memory we set an
upper limit based on nr_free_buffer_pages().  1/2^10 has been too
limiting in practice; 1/2^7 is still less than one percent.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
fs/nfsd/nfssvc.c