LU-10803 ptlrpc: fix req_buffers_max and req_history_max setting

We hit LU-9372 OOM problems, and after applying
LU-9372 ptlrpc: allow to limit number of service's rqbds
we found two problems:

1)Since 0 is a reserved value for @srv_nrqbds_max which
means unlimited value, procfs write interface should support
this value, otherwise, there is no way to change default behavior
back.

2)the check in ptlrpc_lprocfs_req_history_max_seq_write() was broken
after this patch, the following check will always succeed if @srv_nrqbds_max
is kept as default value 0:

val > svc->srv_nrqbds_max/2

Change-Id: Ida0796fa500fe595e003accc11d20fdad5e60c03
Signed-off-by: Wang Shilong <wshilong@ddn.com>
Reviewed-on: https://review.whamcloud.com/31622
Tested-by: Jenkins
Reviewed-by: Faccini Bruno <bruno.faccini@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>

diff --git a/lustre/ptlrpc/lproc_ptlrpc.c b/lustre/ptlrpc/lproc_ptlrpc.c
index ee4e78e..f46f3d5 100644 (file)
--- a/lustre/ptlrpc/lproc_ptlrpc.c
+++ b/lustre/ptlrpc/lproc_ptlrpc.c
@@ -324,8 +324,8 @@ ptlrpc_lprocfs_req_history_max_seq_write(struct file *file,
        bufpages = (roundup_pow_of_two(svc->srv_buf_size) + PAGE_SIZE - 1) >>
                                                        PAGE_SHIFT;
        /* do not allow history to consume more than half max number of rqbds */
-       if ((svc->srv_nrqbds_max == 0 && val > totalram_pages/(2 * bufpages)) ||
-           val > svc->srv_nrqbds_max/2)
+       if ((svc->srv_nrqbds_max == 0 && val > totalram_pages / (2 * bufpages)) ||
+           (svc->srv_nrqbds_max != 0 && val > svc->srv_nrqbds_max / 2))
                return -ERANGE;
 
        spin_lock(&svc->srv_lock);
@@ -365,7 +365,7 @@ ptlrpc_lprocfs_req_buffers_max_seq_write(struct file *file,
        if (rc < 0)
                return rc;
 
-       if (val < svc->srv_nbuf_per_group)
+       if (val < svc->srv_nbuf_per_group && val != 0)
                return -ERANGE;
 
        spin_lock(&svc->srv_lock);