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Message-ID: <CADvbK_dpCoYgVCX=-Bx7T=Hfr2dJUW_RFAGHLj7yXOYX9HPinA@mail.gmail.com>
Date: Fri, 19 Dec 2025 12:10:27 -0500
From: Xin Long <lucien.xin@...il.com>
To: Joe Damato <joe@...a.to>
Cc: netdev@...r.kernel.org, corbet@....net, hdanton@...a.com,
bagasdotme@...il.com, pabeni@...hat.com, namangulati@...gle.com,
edumazet@...gle.com, sridhar.samudrala@...el.com, sdf@...ichev.me,
peter@...eblog.net, m2shafiei@...terloo.ca, bjorn@...osinc.com,
hch@...radead.org, willy@...radead.org, willemdebruijn.kernel@...il.com,
skhawaja@...gle.com, kuba@...nel.org, Martin Karsten <mkarsten@...terloo.ca>,
"David S. Miller" <davem@...emloft.net>, Simon Horman <horms@...nel.org>, Shuah Khan <shuah@...nel.org>,
open list <linux-kernel@...r.kernel.org>,
"open list:KERNEL SELFTEST FRAMEWORK" <linux-kselftest@...r.kernel.org>
Subject: Re: [PATCH net-next v9 5/6] selftests: net: Add busy_poll_test
On Fri, Dec 19, 2025 at 12:05 PM Xin Long <lucien.xin@...il.com> wrote:
>
> On Sat, Nov 9, 2024 at 12:04 AM Joe Damato <jdamato@...tly.com> wrote:
> >
> > Add an epoll busy poll test using netdevsim.
> >
> > This test is comprised of:
> > - busy_poller (via busy_poller.c)
> > - busy_poll_test.sh which loads netdevsim, sets up network namespaces,
> > and runs busy_poller to receive data and socat to send data.
> >
> > The selftest tests two different scenarios:
> > - busy poll (the pre-existing version in the kernel)
> > - busy poll with suspend enabled (what this series adds)
> >
> > The data transmit is a 1MiB temporary file generated from /dev/urandom
> > and the test is considered passing if the md5sum of the input file to
> > socat matches the md5sum of the output file from busy_poller.
> >
> > netdevsim was chosen instead of veth due to netdevsim's support for
> > netdev-genl.
> >
> > For now, this test uses the functionality that netdevsim provides. In the
> > future, perhaps netdevsim can be extended to emulate device IRQs to more
> > thoroughly test all pre-existing kernel options (like defer_hard_irqs)
> > and suspend.
> >
> Hi, Joe,
>
> While running this test, I consistently hit the following failure:
>
> # ./busy_poll_test.sh
> 2025/12/19 11:56:46 socat[8169] E connect(6, AF=2 192.168.1.1:48675,
> 16): Connection timed out
>
> After investigating, I noticed that both netdevsim devices remain in
> the DOWN state:
>
> # ip net exec nssv ip link
> 25: eni374np1@...6: <NO-CARRIER,BROADCAST,UP> mtu 1500 qdisc noqueue
> state DOWN mode DEFAULT group default qlen 1000
> link/ether 2e:5f:c8:84:82:e5 brd ff:ff:ff:ff:ff:ff
> # ip net exec nscl ip link
> 26: eni765np1@...5: <NO-CARRIER,BROADCAST,UP> mtu 1500 qdisc noqueue
> state DOWN mode DEFAULT group default qlen 1000
> link/ether ee:78:d1:b7:d6:00 brd ff:ff:ff:ff:ff:ff
>
> It appears that linking two netdevsim devices does not automatically
> bring the interfaces up. As a workaround, I moved the following
> commands out of setup_ns() and placed them after the netdevsim devices
> are linked:
>
> ip netns exec nssv ip link set dev $NSIM_SV_NAME up
> ip netns exec nscl ip link set dev $NSIM_CL_NAME up
>
> With this change, the test runs successfully.
>
> Do you think I’m missing something here, or is this the expected behavior?
>
Added Joe Damato <joe@...a.to>.
Thanks.
> Thanks.
>
> > Signed-off-by: Joe Damato <jdamato@...tly.com>
> > Co-developed-by: Martin Karsten <mkarsten@...terloo.ca>
> > Signed-off-by: Martin Karsten <mkarsten@...terloo.ca>
> > Acked-by: Stanislav Fomichev <sdf@...ichev.me>
> > ---
> > v9:
> > - Based on feedback from Willem, in busy_poll_test.sh:
> > - shortened long lines,
> > - used more reader friendly variable names
> > - moved constants into variables
> > - fixed the SPDX-License-Identifier
> > - reduced code duplication
> > - In busy_poller.c:
> > - Added a comment explaining the ifdef blob
> > - Fixed some types for strtoul and added explicit casts
> >
> > v5:
> > - Updated commit message to replace netcat with socat and fixed
> > misspelling of netdevsim. No functional/code changes.
> >
> > v4:
> > - Updated busy_poll_test.sh:
> > - use socat instead of nc
> > - drop cli.py usage from the script
> > - removed check_ynl
> > - Updated busy_poller.c:
> > - use netlink to configure napi parameters
> >
> > v3:
> > - New in v3
> >
> > tools/testing/selftests/net/.gitignore | 1 +
> > tools/testing/selftests/net/Makefile | 3 +-
> > tools/testing/selftests/net/busy_poll_test.sh | 165 +++++++++
> > tools/testing/selftests/net/busy_poller.c | 346 ++++++++++++++++++
> > 4 files changed, 514 insertions(+), 1 deletion(-)
> > create mode 100755 tools/testing/selftests/net/busy_poll_test.sh
> > create mode 100644 tools/testing/selftests/net/busy_poller.c
> >
> > diff --git a/tools/testing/selftests/net/.gitignore b/tools/testing/selftests/net/.gitignore
> > index 217d8b7a7365..85b0c4a2179f 100644
> > --- a/tools/testing/selftests/net/.gitignore
> > +++ b/tools/testing/selftests/net/.gitignore
> > @@ -2,6 +2,7 @@
> > bind_bhash
> > bind_timewait
> > bind_wildcard
> > +busy_poller
> > cmsg_sender
> > diag_uid
> > epoll_busy_poll
> > diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
> > index 26a4883a65c9..3ccfe454db1a 100644
> > --- a/tools/testing/selftests/net/Makefile
> > +++ b/tools/testing/selftests/net/Makefile
> > @@ -96,9 +96,10 @@ TEST_PROGS += fdb_flush.sh
> > TEST_PROGS += fq_band_pktlimit.sh
> > TEST_PROGS += vlan_hw_filter.sh
> > TEST_PROGS += bpf_offload.py
> > +TEST_PROGS += busy_poll_test.sh
> >
> > # YNL files, must be before "include ..lib.mk"
> > -YNL_GEN_FILES := ncdevmem
> > +YNL_GEN_FILES := ncdevmem busy_poller
> > TEST_GEN_FILES += $(YNL_GEN_FILES)
> >
> > TEST_FILES := settings
> > diff --git a/tools/testing/selftests/net/busy_poll_test.sh b/tools/testing/selftests/net/busy_poll_test.sh
> > new file mode 100755
> > index 000000000000..7db292ec4884
> > --- /dev/null
> > +++ b/tools/testing/selftests/net/busy_poll_test.sh
> > @@ -0,0 +1,165 @@
> > +#!/bin/bash
> > +# SPDX-License-Identifier: GPL-2.0
> > +source net_helper.sh
> > +
> > +NSIM_SV_ID=$((256 + RANDOM % 256))
> > +NSIM_SV_SYS=/sys/bus/netdevsim/devices/netdevsim$NSIM_SV_ID
> > +NSIM_CL_ID=$((512 + RANDOM % 256))
> > +NSIM_CL_SYS=/sys/bus/netdevsim/devices/netdevsim$NSIM_CL_ID
> > +
> > +NSIM_DEV_SYS_NEW=/sys/bus/netdevsim/new_device
> > +NSIM_DEV_SYS_DEL=/sys/bus/netdevsim/del_device
> > +NSIM_DEV_SYS_LINK=/sys/bus/netdevsim/link_device
> > +NSIM_DEV_SYS_UNLINK=/sys/bus/netdevsim/unlink_device
> > +
> > +SERVER_IP=192.168.1.1
> > +CLIENT_IP=192.168.1.2
> > +SERVER_PORT=48675
> > +
> > +# busy poll config
> > +MAX_EVENTS=8
> > +BUSY_POLL_USECS=0
> > +BUSY_POLL_BUDGET=16
> > +PREFER_BUSY_POLL=1
> > +
> > +# IRQ deferral config
> > +NAPI_DEFER_HARD_IRQS=100
> > +GRO_FLUSH_TIMEOUT=50000
> > +SUSPEND_TIMEOUT=20000000
> > +
> > +setup_ns()
> > +{
> > + set -e
> > + ip netns add nssv
> > + ip netns add nscl
> > +
> > + NSIM_SV_NAME=$(find $NSIM_SV_SYS/net -maxdepth 1 -type d ! \
> > + -path $NSIM_SV_SYS/net -exec basename {} \;)
> > + NSIM_CL_NAME=$(find $NSIM_CL_SYS/net -maxdepth 1 -type d ! \
> > + -path $NSIM_CL_SYS/net -exec basename {} \;)
> > +
> > + # ensure the server has 1 queue
> > + ethtool -L $NSIM_SV_NAME combined 1 2>/dev/null
> > +
> > + ip link set $NSIM_SV_NAME netns nssv
> > + ip link set $NSIM_CL_NAME netns nscl
> > +
> > + ip netns exec nssv ip addr add "${SERVER_IP}/24" dev $NSIM_SV_NAME
> > + ip netns exec nscl ip addr add "${CLIENT_IP}/24" dev $NSIM_CL_NAME
> > +
> > + ip netns exec nssv ip link set dev $NSIM_SV_NAME up
> > + ip netns exec nscl ip link set dev $NSIM_CL_NAME up
> > +
> > + set +e
> > +}
> > +
> > +cleanup_ns()
> > +{
> > + ip netns del nscl
> > + ip netns del nssv
> > +}
> > +
> > +test_busypoll()
> > +{
> > + suspend_value=${1:-0}
> > + tmp_file=$(mktemp)
> > + out_file=$(mktemp)
> > +
> > + # fill a test file with random data
> > + dd if=/dev/urandom of=${tmp_file} bs=1M count=1 2> /dev/null
> > +
> > + timeout -k 1s 30s ip netns exec nssv ./busy_poller \
> > + -p${SERVER_PORT} \
> > + -b${SERVER_IP} \
> > + -m${MAX_EVENTS} \
> > + -u${BUSY_POLL_USECS} \
> > + -P${PREFER_BUSY_POLL} \
> > + -g${BUSY_POLL_BUDGET} \
> > + -i${NSIM_SV_IFIDX} \
> > + -s${suspend_value} \
> > + -o${out_file}&
> > +
> > + wait_local_port_listen nssv ${SERVER_PORT} tcp
> > +
> > + ip netns exec nscl socat -u $tmp_file TCP:${SERVER_IP}:${SERVER_PORT}
> > +
> > + wait
> > +
> > + tmp_file_md5sum=$(md5sum $tmp_file | cut -f1 -d' ')
> > + out_file_md5sum=$(md5sum $out_file | cut -f1 -d' ')
> > +
> > + if [ "$tmp_file_md5sum" = "$out_file_md5sum" ]; then
> > + res=0
> > + else
> > + echo "md5sum mismatch"
> > + echo "input file md5sum: ${tmp_file_md5sum}";
> > + echo "output file md5sum: ${out_file_md5sum}";
> > + res=1
> > + fi
> > +
> > + rm $out_file $tmp_file
> > +
> > + return $res
> > +}
> > +
> > +test_busypoll_with_suspend()
> > +{
> > + test_busypoll ${SUSPEND_TIMEOUT}
> > +
> > + return $?
> > +}
> > +
> > +###
> > +### Code start
> > +###
> > +
> > +modprobe netdevsim
> > +
> > +# linking
> > +
> > +echo $NSIM_SV_ID > $NSIM_DEV_SYS_NEW
> > +echo $NSIM_CL_ID > $NSIM_DEV_SYS_NEW
> > +udevadm settle
> > +
> > +setup_ns
> > +
> > +NSIM_SV_FD=$((256 + RANDOM % 256))
> > +exec {NSIM_SV_FD}</var/run/netns/nssv
> > +NSIM_SV_IFIDX=$(ip netns exec nssv cat /sys/class/net/$NSIM_SV_NAME/ifindex)
> > +
> > +NSIM_CL_FD=$((256 + RANDOM % 256))
> > +exec {NSIM_CL_FD}</var/run/netns/nscl
> > +NSIM_CL_IFIDX=$(ip netns exec nscl cat /sys/class/net/$NSIM_CL_NAME/ifindex)
> > +
> > +echo "$NSIM_SV_FD:$NSIM_SV_IFIDX $NSIM_CL_FD:$NSIM_CL_IFIDX" > \
> > + $NSIM_DEV_SYS_LINK
> > +
> > +if [ $? -ne 0 ]; then
> > + echo "linking netdevsim1 with netdevsim2 should succeed"
> > + cleanup_ns
> > + exit 1
> > +fi
> > +
> > +test_busypoll
> > +if [ $? -ne 0 ]; then
> > + echo "test_busypoll failed"
> > + cleanup_ns
> > + exit 1
> > +fi
> > +
> > +test_busypoll_with_suspend
> > +if [ $? -ne 0 ]; then
> > + echo "test_busypoll_with_suspend failed"
> > + cleanup_ns
> > + exit 1
> > +fi
> > +
> > +echo "$NSIM_SV_FD:$NSIM_SV_IFIDX" > $NSIM_DEV_SYS_UNLINK
> > +
> > +echo $NSIM_CL_ID > $NSIM_DEV_SYS_DEL
> > +
> > +cleanup_ns
> > +
> > +modprobe -r netdevsim
> > +
> > +exit 0
> > diff --git a/tools/testing/selftests/net/busy_poller.c b/tools/testing/selftests/net/busy_poller.c
> > new file mode 100644
> > index 000000000000..99b0e8c17fca
> > --- /dev/null
> > +++ b/tools/testing/selftests/net/busy_poller.c
> > @@ -0,0 +1,346 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +#include <assert.h>
> > +#include <errno.h>
> > +#include <error.h>
> > +#include <fcntl.h>
> > +#include <inttypes.h>
> > +#include <limits.h>
> > +#include <stdlib.h>
> > +#include <stdio.h>
> > +#include <string.h>
> > +#include <unistd.h>
> > +#include <ynl.h>
> > +
> > +#include <arpa/inet.h>
> > +#include <netinet/in.h>
> > +
> > +#include <sys/epoll.h>
> > +#include <sys/ioctl.h>
> > +#include <sys/socket.h>
> > +#include <sys/types.h>
> > +
> > +#include <linux/genetlink.h>
> > +#include <linux/netlink.h>
> > +
> > +#include "netdev-user.h"
> > +
> > +/* The below ifdef blob is required because:
> > + *
> > + * - sys/epoll.h does not (yet) have the ioctl definitions included. So,
> > + * systems with older glibcs will not have them available. However,
> > + * sys/epoll.h does include the type definition for epoll_data, which is
> > + * needed by the user program (e.g. epoll_event.data.fd)
> > + *
> > + * - linux/eventpoll.h does not define the epoll_data type, it is simply an
> > + * opaque __u64. It does, however, include the ioctl definition.
> > + *
> > + * Including both headers is impossible (types would be redefined), so I've
> > + * opted instead to take sys/epoll.h, and include the blob below.
> > + *
> > + * Someday, when glibc is globally up to date, the blob below can be removed.
> > + */
> > +#if !defined(EPOLL_IOC_TYPE)
> > +struct epoll_params {
> > + uint32_t busy_poll_usecs;
> > + uint16_t busy_poll_budget;
> > + uint8_t prefer_busy_poll;
> > +
> > + /* pad the struct to a multiple of 64bits */
> > + uint8_t __pad;
> > +};
> > +
> > +#define EPOLL_IOC_TYPE 0x8A
> > +#define EPIOCSPARAMS _IOW(EPOLL_IOC_TYPE, 0x01, struct epoll_params)
> > +#define EPIOCGPARAMS _IOR(EPOLL_IOC_TYPE, 0x02, struct epoll_params)
> > +#endif
> > +
> > +static uint32_t cfg_port = 8000;
> > +static struct in_addr cfg_bind_addr = { .s_addr = INADDR_ANY };
> > +static char *cfg_outfile;
> > +static int cfg_max_events = 8;
> > +static int cfg_ifindex;
> > +
> > +/* busy poll params */
> > +static uint32_t cfg_busy_poll_usecs;
> > +static uint32_t cfg_busy_poll_budget;
> > +static uint32_t cfg_prefer_busy_poll;
> > +
> > +/* IRQ params */
> > +static uint32_t cfg_defer_hard_irqs;
> > +static uint64_t cfg_gro_flush_timeout;
> > +static uint64_t cfg_irq_suspend_timeout;
> > +
> > +static void usage(const char *filepath)
> > +{
> > + error(1, 0,
> > + "Usage: %s -p<port> -b<addr> -m<max_events> -u<busy_poll_usecs> -P<prefer_busy_poll> -g<busy_poll_budget> -o<outfile> -d<defer_hard_irqs> -r<gro_flush_timeout> -s<irq_suspend_timeout> -i<ifindex>",
> > + filepath);
> > +}
> > +
> > +static void parse_opts(int argc, char **argv)
> > +{
> > + int ret;
> > + int c;
> > +
> > + if (argc <= 1)
> > + usage(argv[0]);
> > +
> > + while ((c = getopt(argc, argv, "p:m:b:u:P:g:o:d:r:s:i:")) != -1) {
> > + switch (c) {
> > + case 'u':
> > + cfg_busy_poll_usecs = strtoul(optarg, NULL, 0);
> > + if (cfg_busy_poll_usecs == ULONG_MAX ||
> > + cfg_busy_poll_usecs > UINT32_MAX)
> > + error(1, ERANGE, "busy_poll_usecs too large");
> > + break;
> > + case 'P':
> > + cfg_prefer_busy_poll = strtoul(optarg, NULL, 0);
> > + if (cfg_prefer_busy_poll == ULONG_MAX ||
> > + cfg_prefer_busy_poll > 1)
> > + error(1, ERANGE,
> > + "prefer busy poll should be 0 or 1");
> > + break;
> > + case 'g':
> > + cfg_busy_poll_budget = strtoul(optarg, NULL, 0);
> > + if (cfg_busy_poll_budget == ULONG_MAX ||
> > + cfg_busy_poll_budget > UINT16_MAX)
> > + error(1, ERANGE,
> > + "busy poll budget must be [0, UINT16_MAX]");
> > + break;
> > + case 'p':
> > + cfg_port = strtoul(optarg, NULL, 0);
> > + if (cfg_port > UINT16_MAX)
> > + error(1, ERANGE, "port must be <= 65535");
> > + break;
> > + case 'b':
> > + ret = inet_aton(optarg, &cfg_bind_addr);
> > + if (ret == 0)
> > + error(1, errno,
> > + "bind address %s invalid", optarg);
> > + break;
> > + case 'o':
> > + cfg_outfile = strdup(optarg);
> > + if (!cfg_outfile)
> > + error(1, 0, "outfile invalid");
> > + break;
> > + case 'm':
> > + cfg_max_events = strtol(optarg, NULL, 0);
> > +
> > + if (cfg_max_events == LONG_MIN ||
> > + cfg_max_events == LONG_MAX ||
> > + cfg_max_events <= 0)
> > + error(1, ERANGE,
> > + "max events must be > 0 and < LONG_MAX");
> > + break;
> > + case 'd':
> > + cfg_defer_hard_irqs = strtoul(optarg, NULL, 0);
> > +
> > + if (cfg_defer_hard_irqs == ULONG_MAX ||
> > + cfg_defer_hard_irqs > INT32_MAX)
> > + error(1, ERANGE,
> > + "defer_hard_irqs must be <= INT32_MAX");
> > + break;
> > + case 'r':
> > + cfg_gro_flush_timeout = strtoull(optarg, NULL, 0);
> > +
> > + if (cfg_gro_flush_timeout == ULLONG_MAX)
> > + error(1, ERANGE,
> > + "gro_flush_timeout must be < ULLONG_MAX");
> > + break;
> > + case 's':
> > + cfg_irq_suspend_timeout = strtoull(optarg, NULL, 0);
> > +
> > + if (cfg_irq_suspend_timeout == ULLONG_MAX)
> > + error(1, ERANGE,
> > + "irq_suspend_timeout must be < ULLONG_MAX");
> > + break;
> > + case 'i':
> > + cfg_ifindex = strtoul(optarg, NULL, 0);
> > + if (cfg_ifindex == ULONG_MAX)
> > + error(1, ERANGE,
> > + "ifindex must be < ULONG_MAX");
> > + break;
> > + }
> > + }
> > +
> > + if (!cfg_ifindex)
> > + usage(argv[0]);
> > +
> > + if (optind != argc)
> > + usage(argv[0]);
> > +}
> > +
> > +static void epoll_ctl_add(int epfd, int fd, uint32_t events)
> > +{
> > + struct epoll_event ev;
> > +
> > + ev.events = events;
> > + ev.data.fd = fd;
> > + if (epoll_ctl(epfd, EPOLL_CTL_ADD, fd, &ev) == -1)
> > + error(1, errno, "epoll_ctl add fd: %d", fd);
> > +}
> > +
> > +static void setnonblock(int sockfd)
> > +{
> > + int flags;
> > +
> > + flags = fcntl(sockfd, F_GETFL, 0);
> > +
> > + if (fcntl(sockfd, F_SETFL, flags | O_NONBLOCK) == -1)
> > + error(1, errno, "unable to set socket to nonblocking mode");
> > +}
> > +
> > +static void write_chunk(int fd, char *buf, ssize_t buflen)
> > +{
> > + ssize_t remaining = buflen;
> > + char *buf_offset = buf;
> > + ssize_t writelen = 0;
> > + ssize_t write_result;
> > +
> > + while (writelen < buflen) {
> > + write_result = write(fd, buf_offset, remaining);
> > + if (write_result == -1)
> > + error(1, errno, "unable to write data to outfile");
> > +
> > + writelen += write_result;
> > + remaining -= write_result;
> > + buf_offset += write_result;
> > + }
> > +}
> > +
> > +static void setup_queue(void)
> > +{
> > + struct netdev_napi_get_list *napi_list = NULL;
> > + struct netdev_napi_get_req_dump *req = NULL;
> > + struct netdev_napi_set_req *set_req = NULL;
> > + struct ynl_sock *ys;
> > + struct ynl_error yerr;
> > + uint32_t napi_id;
> > +
> > + ys = ynl_sock_create(&ynl_netdev_family, &yerr);
> > + if (!ys)
> > + error(1, 0, "YNL: %s", yerr.msg);
> > +
> > + req = netdev_napi_get_req_dump_alloc();
> > + netdev_napi_get_req_dump_set_ifindex(req, cfg_ifindex);
> > + napi_list = netdev_napi_get_dump(ys, req);
> > +
> > + /* assume there is 1 NAPI configured and take the first */
> > + if (napi_list->obj._present.id)
> > + napi_id = napi_list->obj.id;
> > + else
> > + error(1, 0, "napi ID not present?");
> > +
> > + set_req = netdev_napi_set_req_alloc();
> > + netdev_napi_set_req_set_id(set_req, napi_id);
> > + netdev_napi_set_req_set_defer_hard_irqs(set_req, cfg_defer_hard_irqs);
> > + netdev_napi_set_req_set_gro_flush_timeout(set_req,
> > + cfg_gro_flush_timeout);
> > + netdev_napi_set_req_set_irq_suspend_timeout(set_req,
> > + cfg_irq_suspend_timeout);
> > +
> > + if (netdev_napi_set(ys, set_req))
> > + error(1, 0, "can't set NAPI params: %s\n", yerr.msg);
> > +
> > + netdev_napi_get_list_free(napi_list);
> > + netdev_napi_get_req_dump_free(req);
> > + netdev_napi_set_req_free(set_req);
> > + ynl_sock_destroy(ys);
> > +}
> > +
> > +static void run_poller(void)
> > +{
> > + struct epoll_event events[cfg_max_events];
> > + struct epoll_params epoll_params = {0};
> > + struct sockaddr_in server_addr;
> > + int i, epfd, nfds;
> > + ssize_t readlen;
> > + int outfile_fd;
> > + char buf[1024];
> > + int sockfd;
> > + int conn;
> > + int val;
> > +
> > + outfile_fd = open(cfg_outfile, O_WRONLY | O_CREAT, 0644);
> > + if (outfile_fd == -1)
> > + error(1, errno, "unable to open outfile: %s", cfg_outfile);
> > +
> > + sockfd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
> > + if (sockfd == -1)
> > + error(1, errno, "unable to create listen socket");
> > +
> > + server_addr.sin_family = AF_INET;
> > + server_addr.sin_port = htons(cfg_port);
> > + server_addr.sin_addr = cfg_bind_addr;
> > +
> > + /* these values are range checked during parse_opts, so casting is safe
> > + * here
> > + */
> > + epoll_params.busy_poll_usecs = cfg_busy_poll_usecs;
> > + epoll_params.busy_poll_budget = (uint16_t)cfg_busy_poll_budget;
> > + epoll_params.prefer_busy_poll = (uint8_t)cfg_prefer_busy_poll;
> > + epoll_params.__pad = 0;
> > +
> > + val = 1;
> > + if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val)))
> > + error(1, errno, "poller setsockopt reuseaddr");
> > +
> > + setnonblock(sockfd);
> > +
> > + if (bind(sockfd, (struct sockaddr *)&server_addr,
> > + sizeof(struct sockaddr_in)))
> > + error(0, errno, "poller bind to port: %d\n", cfg_port);
> > +
> > + if (listen(sockfd, 1))
> > + error(1, errno, "poller listen");
> > +
> > + epfd = epoll_create1(0);
> > + if (ioctl(epfd, EPIOCSPARAMS, &epoll_params) == -1)
> > + error(1, errno, "unable to set busy poll params");
> > +
> > + epoll_ctl_add(epfd, sockfd, EPOLLIN | EPOLLOUT | EPOLLET);
> > +
> > + for (;;) {
> > + nfds = epoll_wait(epfd, events, cfg_max_events, -1);
> > + for (i = 0; i < nfds; i++) {
> > + if (events[i].data.fd == sockfd) {
> > + conn = accept(sockfd, NULL, NULL);
> > + if (conn == -1)
> > + error(1, errno,
> > + "accepting incoming connection failed");
> > +
> > + setnonblock(conn);
> > + epoll_ctl_add(epfd, conn,
> > + EPOLLIN | EPOLLET | EPOLLRDHUP |
> > + EPOLLHUP);
> > + } else if (events[i].events & EPOLLIN) {
> > + for (;;) {
> > + readlen = read(events[i].data.fd, buf,
> > + sizeof(buf));
> > + if (readlen > 0)
> > + write_chunk(outfile_fd, buf,
> > + readlen);
> > + else
> > + break;
> > + }
> > + } else {
> > + /* spurious event ? */
> > + }
> > + if (events[i].events & (EPOLLRDHUP | EPOLLHUP)) {
> > + epoll_ctl(epfd, EPOLL_CTL_DEL,
> > + events[i].data.fd, NULL);
> > + close(events[i].data.fd);
> > + close(outfile_fd);
> > + return;
> > + }
> > + }
> > + }
> > +}
> > +
> > +int main(int argc, char *argv[])
> > +{
> > + parse_opts(argc, argv);
> > + setup_queue();
> > + run_poller();
> > + return 0;
> > +}
> > --
> > 2.25.1
> >
> >
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