[ 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 | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c index e02bd2783124..4a9e0fb634b6 100644 --- a/fs/nfsd/nfssvc.c +++ b/fs/nfsd/nfssvc.c @@ -447,7 +447,7 @@ void nfsd_reset_versions(void) */ static void set_max_drc(void) { - #define NFSD_DRC_SIZE_SHIFT 10 + #define NFSD_DRC_SIZE_SHIFT 7 nfsd_drc_max_mem = (nr_free_buffer_pages() >> NFSD_DRC_SIZE_SHIFT) * PAGE_SIZE; nfsd_drc_mem_used = 0;