Re: [PATCH net-next 06/11] bnxt_en: Improve -ENOMEM logic in NAPI poll loop.
From: Martin KaFai Lau <hidden>
Date: 2017-08-28 19:05:09
On Mon, Aug 28, 2017 at 01:40:30PM -0400, Michael Chan wrote:
If we cannot allocate RX buffers in the NAPI poll loop when processing an RX event, the current code does not count that event towards the NAPI budget. This can cause us to potentially loop forever in NAPI if we consistently cannot allocate new buffers. Improve it by counting -ENOMEM event as 1 towards the NAPI budget. Cc: Martin KaFai Lau <redacted> Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Thanks for fixing it. Reported-by: Martin KaFai Lau <redacted> Acked-by: Martin KaFai Lau <redacted>
quoted hunk ↗ jump to hunk
--- drivers/net/ethernet/broadcom/bnxt/bnxt.c | 7 +++++++ 1 file changed, 7 insertions(+)diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c index 1afb408..a34fcdd 100644 --- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c@@ -1850,6 +1850,13 @@ static int bnxt_poll_work(struct bnxt *bp, struct bnxt_napi *bnapi, int budget) &event); if (likely(rc >= 0)) rx_pkts += rc; + /* Increment rx_pkts when rc is -ENOMEM to count towards + * the NAPI budget. Otherwise, we may potentially loop + * here forever if we consistently cannot allocate + * buffers. + */ + else if (rc == -ENOMEM) + rx_pkts++; else if (rc == -EBUSY) /* partial completion */ break; } else if (unlikely((TX_CMP_TYPE(txcmp) == --1.8.3.1