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Date: Wed, 16 Sep 2020 14:15:08 -0700 From: Manjunath Patil <manjunath.b.patil@...cle.com> To: santosh.shilimkar@...cle.com Cc: netdev@...r.kernel.org, linux-rdma@...r.kernel.org, aruna.ramakrishna@...cle.com, rama.nichanamatlu@...cle.com Subject: Re: [PATCH 1/1] net/rds: suppress page allocation failure error in recv buffer refill Hi Santosh, inline. On 9/16/2020 12:27 PM, santosh.shilimkar@...cle.com wrote: > On 9/16/20 12:08 PM, Manjunath Patil wrote: >> RDS/IB tries to refill the recv buffer in softirq context using >> GFP_NOWAIT flag. However alloc failure is handled by queueing a work to >> refill the recv buffer with GFP_KERNEL flag. This means failure to >> allocate with GFP_NOWAIT isn't fatal. Do not print the PAF warnings if >> softirq context fails to refill the recv buffer, instead print a one >> line warning once a day. >> >> Signed-off-by: Manjunath Patil <manjunath.b.patil@...cle.com> >> Reviewed-by: Aruna Ramakrishna <aruna.ramakrishna@...cle.com> >> --- >> net/rds/ib_recv.c | 16 +++++++++++++--- >> 1 file changed, 13 insertions(+), 3 deletions(-) >> >> diff --git a/net/rds/ib_recv.c b/net/rds/ib_recv.c >> index 694d411dc72f..38d2894f6bb2 100644 >> --- a/net/rds/ib_recv.c >> +++ b/net/rds/ib_recv.c >> @@ -310,8 +310,8 @@ static int rds_ib_recv_refill_one(struct >> rds_connection *conn, >> struct rds_ib_connection *ic = conn->c_transport_data; >> struct ib_sge *sge; >> int ret = -ENOMEM; >> - gfp_t slab_mask = GFP_NOWAIT; >> - gfp_t page_mask = GFP_NOWAIT; >> + gfp_t slab_mask = gfp; >> + gfp_t page_mask = gfp; >> if (gfp & __GFP_DIRECT_RECLAIM) { >> slab_mask = GFP_KERNEL; >> @@ -406,6 +406,16 @@ void rds_ib_recv_refill(struct rds_connection >> *conn, int prefill, gfp_t gfp) >> recv = &ic->i_recvs[pos]; >> ret = rds_ib_recv_refill_one(conn, recv, gfp); >> if (ret) { >> + static unsigned long warn_time; > Comment should start on next line. I will add new line. checkpatch.pl didn't find it though. >> + /* warn max once per day. This should be enough to >> + * warn users about low mem situation. >> + */ >> + if (printk_timed_ratelimit(&warn_time, >> + 24 * 60 * 60 * 1000)) >> + pr_warn("RDS/IB: failed to refill recv buffer for >> <%pI6c,%pI6c,%d>, waking worker\n", >> + &conn->c_laddr, &conn->c_faddr, >> + conn->c_tos); > Didn't notice this before. > Why not just use "pr_warn_ratelimited()" ? I think you meant, get rid of if clause and use "pr_warn_ratelimited()" instead. That can still produce more than needed logs during low memory situation. -Thanks, Manjunath >> + >> must_wake = true; >> break; >> } >> @@ -1020,7 +1030,7 @@ void rds_ib_recv_cqe_handler(struct >> rds_ib_connection *ic, >> rds_ib_stats_inc(s_ib_rx_ring_empty); >> if (rds_ib_ring_low(&ic->i_recv_ring)) { >> - rds_ib_recv_refill(conn, 0, GFP_NOWAIT); >> + rds_ib_recv_refill(conn, 0, GFP_NOWAIT | __GFP_NOWARN); >> rds_ib_stats_inc(s_ib_rx_refill_from_cq); >> } >> } >>
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