On Tue, 13 Oct 2026 22:00:16 +0800 Zhang Tengfei <[email protected]> wrote:
> Enabling Flow Director reduces the Rx packet buffer 0 to reserve memory > for the filter table, but the size was computed from the current > register value and never restored when FDIR was no longer used. Since > the FDIR mode is reset when the last rule is removed, on flush, or when > enabling FDIR fails, the next rule enabled FDIR again and shrank the > buffer once more, until it underflowed. Validating a rule also enabled > FDIR. > > Patch 1 computes the buffer size from the default packet buffer size, > which alone stops the repeated reduction. > Patch 2 stops enabling FDIR from flow validate and rolls back the mode > when the first rule fails. > Patch 3 disables FDIR and restores the buffer when no rule is left. > > The same issue was fixed in ixgbe: > <https://patches.dpdk.org/project/dpdk/patch/[email protected]> > > Compile tested only. > > Zhang Tengfei (3): > net/txgbe: fix Rx packet buffer size with flow director > net/txgbe: do not enable flow director on flow validate > net/txgbe: disable flow director when no rule is left > > drivers/net/txgbe/txgbe_ethdev.h | 1 + > drivers/net/txgbe/txgbe_fdir.c | 36 +++++++++++++++---- > drivers/net/txgbe/txgbe_flow.c | 60 +++++++++++++++++--------------- > 3 files changed, 62 insertions(+), 35 deletions(-) > AI review saw a warning that would be easy to fix. Subject: Re: [PATCH 0/3] net/txgbe: flow director state fixes Applied to main, each commit builds with -Dwerror=true. Fixes: tags check out. Series looks right overall; one validate regression in 2/3. [PATCH 2/3] net/txgbe: do not enable flow director on flow validate Warning: validate now accepts rules that create will always reject. txgbe_parse_fdir_filter_normal() can set rule->mode = RTE_FDIR_MODE_PERFECT_MAC_VLAN. Before this patch, with mode NONE, parse called txgbe_fdir_configure() which returns -ENOSYS for anything other than SIGNATURE or PERFECT, so validate failed. Now parse only checks for a mode mismatch, validate succeeds, and create fails later in txgbe_fdir_configure(). Keep the cheap mode check in parse so validate and create agree: if (rule->mode != RTE_FDIR_MODE_SIGNATURE && rule->mode != RTE_FDIR_MODE_PERFECT) return -ENOTSUP; if (fdir_conf->mode != RTE_FDIR_MODE_NONE && fdir_conf->mode != rule->mode) return -ENOTSUP; [PATCH 3/3] net/txgbe: disable flow director when no rule is left Info: txgbe_fdir_disable() restores a single packet buffer layout (PB0 = rx_pb_size, PB1-7 = 0), not what txgbe_configure_dcb() set at dev_start. That matches what txgbe_fdir_configure() already does, so FDIR with DCB is already broken and this is not a new problem. If you respin, consider saving the PBRXSIZE values before enabling FDIR and restoring them on disable, or reject FDIR when DCB Rx is configured.
