diff options
Diffstat (limited to 'target/linux/generic/backport-5.4/396-5.8-sch_cake-don-t-try-to-reallocate-or-unshare-skb-unco.patch')
| -rw-r--r-- | target/linux/generic/backport-5.4/396-5.8-sch_cake-don-t-try-to-reallocate-or-unshare-skb-unco.patch | 96 |
1 files changed, 0 insertions, 96 deletions
diff --git a/target/linux/generic/backport-5.4/396-5.8-sch_cake-don-t-try-to-reallocate-or-unshare-skb-unco.patch b/target/linux/generic/backport-5.4/396-5.8-sch_cake-don-t-try-to-reallocate-or-unshare-skb-unco.patch deleted file mode 100644 index a36095c26c..0000000000 --- a/target/linux/generic/backport-5.4/396-5.8-sch_cake-don-t-try-to-reallocate-or-unshare-skb-unco.patch +++ /dev/null @@ -1,96 +0,0 @@ -From 9208d2863ac689a563b92f2161d8d1e7127d0add Mon Sep 17 00:00:00 2001 -From: Ilya Ponetayev <i.ponetaev@ndmsystems.com> -Date: Thu, 25 Jun 2020 22:12:07 +0200 -Subject: [PATCH] sch_cake: don't try to reallocate or unshare skb - unconditionally -MIME-Version: 1.0 -Content-Type: text/plain; charset=UTF-8 -Content-Transfer-Encoding: 8bit - -cake_handle_diffserv() tries to linearize mac and network header parts of -skb and to make it writable unconditionally. In some cases it leads to full -skb reallocation, which reduces throughput and increases CPU load. Some -measurements of IPv4 forward + NAPT on MIPS router with 580 MHz single-core -CPU was conducted. It appears that on kernel 4.9 skb_try_make_writable() -reallocates skb, if skb was allocated in ethernet driver via so-called -'build skb' method from page cache (it was discovered by strange increase -of kmalloc-2048 slab at first). - -Obtain DSCP value via read-only skb_header_pointer() call, and leave -linearization only for DSCP bleaching or ECN CE setting. And, as an -additional optimisation, skip diffserv parsing entirely if it is not needed -by the current configuration. - -Fixes: c87b4ecdbe8d ("sch_cake: Make sure we can write the IP header before changing DSCP bits") -Signed-off-by: Ilya Ponetayev <i.ponetaev@ndmsystems.com> -[ fix a few style issues, reflow commit message ] -Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> -Signed-off-by: David S. Miller <davem@davemloft.net> -Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk> ---- - net/sched/sch_cake.c | 41 ++++++++++++++++++++++++++++++----------- - 1 file changed, 30 insertions(+), 11 deletions(-) - ---- a/net/sched/sch_cake.c -+++ b/net/sched/sch_cake.c -@@ -1553,30 +1553,49 @@ static unsigned int cake_drop(struct Qdi - - static u8 cake_handle_diffserv(struct sk_buff *skb, u16 wash) - { -- int wlen = skb_network_offset(skb); -+ const int offset = skb_network_offset(skb); -+ u16 *buf, buf_; - u8 dscp; - - switch (tc_skb_protocol(skb)) { - case htons(ETH_P_IP): -- wlen += sizeof(struct iphdr); -- if (!pskb_may_pull(skb, wlen) || -- skb_try_make_writable(skb, wlen)) -+ buf = skb_header_pointer(skb, offset, sizeof(buf_), &buf_); -+ if (unlikely(!buf)) - return 0; - -- dscp = ipv4_get_dsfield(ip_hdr(skb)) >> 2; -- if (wash && dscp) -+ /* ToS is in the second byte of iphdr */ -+ dscp = ipv4_get_dsfield((struct iphdr *)buf) >> 2; -+ -+ if (wash && dscp) { -+ const int wlen = offset + sizeof(struct iphdr); -+ -+ if (!pskb_may_pull(skb, wlen) || -+ skb_try_make_writable(skb, wlen)) -+ return 0; -+ - ipv4_change_dsfield(ip_hdr(skb), INET_ECN_MASK, 0); -+ } -+ - return dscp; - - case htons(ETH_P_IPV6): -- wlen += sizeof(struct ipv6hdr); -- if (!pskb_may_pull(skb, wlen) || -- skb_try_make_writable(skb, wlen)) -+ buf = skb_header_pointer(skb, offset, sizeof(buf_), &buf_); -+ if (unlikely(!buf)) - return 0; - -- dscp = ipv6_get_dsfield(ipv6_hdr(skb)) >> 2; -- if (wash && dscp) -+ /* Traffic class is in the first and second bytes of ipv6hdr */ -+ dscp = ipv6_get_dsfield((struct ipv6hdr *)buf) >> 2; -+ -+ if (wash && dscp) { -+ const int wlen = offset + sizeof(struct ipv6hdr); -+ -+ if (!pskb_may_pull(skb, wlen) || -+ skb_try_make_writable(skb, wlen)) -+ return 0; -+ - ipv6_change_dsfield(ipv6_hdr(skb), INET_ECN_MASK, 0); -+ } -+ - return dscp; - - case htons(ETH_P_ARP): |