From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Sat, 18 May 2013 07:48:49 -0700 From: Jon Mason To: Jonghwan Choi Cc: stable@vger.kernel.org, linux-kernel@vger.kernel.org, Jonghwan Choi Subject: Re: [PATCH 3.9-stable] NTB: memcpy lockup workaround Message-ID: <20130518144849.GF29066@jonmason-lab> References: <1368845537-4250-1-git-send-email-jhbird.choi@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1368845537-4250-1-git-send-email-jhbird.choi@samsung.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: On Sat, May 18, 2013 at 11:52:17AM +0900, Jonghwan Choi wrote: > From: Jon Mason > > This patch looks like it should be in the 3.9-stable tree, should we apply > it? Yes, thanks. > > ------------------ > > From: "Jon Mason " > > commit c336acd3331dcc191a97dbc66a557d47741657c7 upstream > > The system will appear to lockup for long periods of time due to the NTB > driver spending too much time in memcpy. Avoid this by reducing the > number of packets that can be serviced on a given interrupt. > > Cc: # 3.9.x: ad3e2751: ntb: off by one > Cc: # 3.9.x: cc0f868d: NTB: fix pointer math > Cc: # 3.9.x: 113fc505: NTB: Handle 64bit BAR > Cc: # 3.9.x: b77b2637: NTB: Link toggle memory > Cc: # 3.9.x: 90f9e934: NTB: reset tx_index on > Cc: # 3.9.x: c9d534c8: NTB: Correctly handle receive > Signed-off-by: Jon Mason > Signed-off-by: Jonghwan Choi > --- > drivers/ntb/ntb_transport.c | 11 ++++++++--- > 1 file changed, 8 insertions(+), 3 deletions(-) > > diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c > index a288a26..0f66daa 100644 > --- a/drivers/ntb/ntb_transport.c > +++ b/drivers/ntb/ntb_transport.c > @@ -1034,11 +1034,16 @@ out: > static void ntb_transport_rx(unsigned long data) > { > struct ntb_transport_qp *qp = (struct ntb_transport_qp *)data; > - int rc; > + int rc, i; > > - do { > + /* Limit the number of packets processed in a single interrupt to > + * provide fairness to others > + */ > + for (i = 0; i < qp->rx_max_entry; i++) { > rc = ntb_process_rxc(qp); > - } while (!rc); > + if (rc) > + break; > + } > } > > static void ntb_transport_rxc_db(void *data, int db_num) > -- > 1.8.1.2 >