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Reduce kdump memory consumption by only installing needed NIC drivers

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Even after having asked NM to stop managing a unneeded NIC, a NIC driver
may still waste memory. For example, mlx5_core uses a substantial amount
of memory during driver initialization,

======== Report format module_summary: ========
Module mlx5_core using 350.2MB (89650 pages), peak allocation 367.4MB (94056 pages)
Module squashfs using 13.1MB (3360 pages), peak allocation 13.1MB (3360 pages)
Module overlay using 2.1MB (550 pages), peak allocation 2.2MB (555 pages)
Module dns_resolver using 0.9MB (219 pages), peak allocation 5.2MB (1338 pages)
Module mlxfw using 0.7MB (172 pages), peak allocation 5.3MB (1349 pages)
======== Report format module_summary END ========

======== Report format module_top: ========
Top stack usage of module mlx5_core:
  (null) Pages: 89650 (peak: 94056)
    ret_from_fork (0xffffda088b4165f8) Pages: 60007 (peak: 60007)
      kthread (0xffffda088b4bd7e4) Pages: 60007 (peak: 60007)
        worker_thread (0xffffda088b4b48d0) Pages: 60007 (peak: 60007)
          process_one_work (0xffffda088b4b3f40) Pages: 60007 (peak: 60007)
            work_for_cpu_fn (0xffffda088b4aef00) Pages: 53906 (peak: 53906)
              local_pci_probe (0xffffda088b9e1e44) Pages: 53906 (peak: 53906)
                probe_one mlx5_core (0xffffda084f899cc8) Pages: 53518 (peak: 53518)
                  mlx5_init_one mlx5_core (0xffffda084f8994ac) Pages: 49756 (peak: 49756)
                    mlx5_function_setup.constprop.0 mlx5_core (0xffffda084f899100) Pages: 44434 (eak: 44434)
                      mlx5_satisfy_startup_pages mlx5_core (0xffffda084f8a4f24) Pages: 44434 (peak: 44434)
                    mlx5_function_setup.constprop.0 mlx5_core (0xffffda084f899078) Pages: 5285 (peak: 5285)
                      mlx5_cmd_init mlx5_core (0xffffda084f89e414) Pages: 4818 (peak: 4818)
                        mlx5_alloc_cmd_msg mlx5_core (0xffffda084f89aaa0) Pages: 4403 (peak: 4403)

This memory consumption is completely unnecessary when kdump doesn't need
this NIC. Only install needed NIC drivers to prevent this kind of waste.

Note
1. this patch depends on [1] to ask dracut to not install NIC drivers.
2. "ethtool -i" somehow fails to get the vlan driver
3. team.ko doesn't depend on the team mode drivers so we need to install
   the team mode drivers manually.

[1] https://github.com/dracutdevs/dracut/pull/1789

Signed-off-by: Coiby Xu <coxu@redhat.com>
Reviewed-by: Thomas Haller <thaller@redhat.com>
Reviewed-by: Philipp Rudo <prudo@redhat.com>
This commit is contained in:
Coiby Xu 2022-05-19 11:39:25 +08:00
parent 586fe410aa
commit a65dde2d10
2 changed files with 32 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
dracut-module-setup.sh
View File

@ -387,6 +387,36 @@ EOF
inst "$_netif_allowlist_nm_conf" "/etc/NetworkManager/conf.d/10-kdump-netif_allowlist.conf"
}
_get_nic_driver() {
ethtool -i "$1" | sed -n -E "s/driver: (.*)/\1/p"
}
kdump_install_nic_driver() {
local _netif _driver _drivers
_drivers=()
for _netif in $1; do
_driver=$(_get_nic_driver "$_netif")
if [[ -z $_driver ]]; then
derror "Failed to get the driver of $_netif"
exit 1
fi
if [[ $_driver == "802.1Q VLAN Support" ]]; then
# ethtool somehow doesn't return the driver name for a VLAN NIC
_driver=8021q
elif [[ $_driver == "team" ]]; then
# install the team mode drivers like team_mode_roundrobin.ko as well
_driver='=drivers/net/team'
fi
_drivers+=("$_driver")
done
instmods "${_drivers[@]}"
}
kdump_setup_bridge() {
local _netdev=$1
local _dev
@ -582,6 +612,7 @@ kdump_install_net() {
kdump_install_nmconnections
apply_nm_initrd_generator_timeouts
kdump_install_nm_netif_allowlist "$_netifs"
kdump_install_nic_driver "$_netifs"
fi
}

2
mkdumprd
View File

@ -27,7 +27,7 @@ SAVE_PATH=$(get_save_path)
OVERRIDE_RESETTABLE=0
extra_modules=""
dracut_args=(--add kdumpbase --quiet --hostonly --hostonly-cmdline --hostonly-i18n --hostonly-mode strict -o "plymouth resume ifcfg earlykdump")
dracut_args=(--add kdumpbase --quiet --hostonly --hostonly-cmdline --hostonly-i18n --hostonly-mode strict --hostonly-nics '' -o "plymouth resume ifcfg earlykdump")
MKDUMPRD_TMPDIR="$(mktemp -d -t mkdumprd.XXXXXX)"
[ -d "$MKDUMPRD_TMPDIR" ] || perror_exit "dracut: mktemp -p -d -t dracut.XXXXXX failed."