Ksawlii/kernel_samsung_a53x
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

net-zerocopy: Refactor frag-is-remappable test.

Browse source 
[ Upstream commit 98917cf0d6eda01e8c3c34d35398d46b247b6fd3 ]

Refactor frag-is-remappable test for tcp receive zerocopy. This is
part of a patch set that introduces short-circuited hybrid copies
for small receive operations, which results in roughly 33% fewer
syscalls for small RPC scenarios.

Signed-off-by: Arjun Roy <arjunroy@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Stable-dep-of: 577e4432f3ac ("tcp: add sanity checks to rx zerocopy")
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Arjun Roy 2020-12-02 14:53:45 -08:00 • committed by Ksawlii
parent 7ea875c4fe
commit 2dbe9277ad
1 changed files with 26 additions and 8 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

34
net/ipv4/tcp.c
View file

@ -1784,6 +1784,26 @@ static skb_frag_t *skb_advance_to_frag(struct sk_buff *skb, u32 offset_skb,
return frag; return frag;
} }
static bool can_map_frag(const skb_frag_t *frag)
{
return skb_frag_size(frag) == PAGE_SIZE && !skb_frag_off(frag);
}
static int find_next_mappable_frag(const skb_frag_t *frag,
int remaining_in_skb)
{
int offset = 0;
if (likely(can_map_frag(frag)))
return 0;
while (offset < remaining_in_skb && !can_map_frag(frag)) {
offset += skb_frag_size(frag);
++frag;
}
return offset;
}
static int tcp_copy_straggler_data(struct tcp_zerocopy_receive *zc, static int tcp_copy_straggler_data(struct tcp_zerocopy_receive *zc,
struct sk_buff *skb, u32 copylen, struct sk_buff *skb, u32 copylen,
u32 *offset, u32 *seq) u32 *offset, u32 *seq)
@ -1909,6 +1929,8 @@ static int tcp_zerocopy_receive(struct sock *sk,
ret = 0; ret = 0;
curr_addr = address; curr_addr = address;
while (length + PAGE_SIZE <= zc->length) { while (length + PAGE_SIZE <= zc->length) {
int mappable_offset;
if (zc->recv_skip_hint < PAGE_SIZE) { if (zc->recv_skip_hint < PAGE_SIZE) {
u32 offset_frag; u32 offset_frag;
@ -1936,15 +1958,11 @@ static int tcp_zerocopy_receive(struct sock *sk,
if (!frags || offset_frag) if (!frags || offset_frag)
break; break;
} }
if (skb_frag_size(frags) != PAGE_SIZE || skb_frag_off(frags)) {
int remaining = zc->recv_skip_hint;
while (remaining && (skb_frag_size(frags) != PAGE_SIZE || mappable_offset = find_next_mappable_frag(frags,
skb_frag_off(frags))) { zc->recv_skip_hint);
remaining -= skb_frag_size(frags); if (mappable_offset) {
frags++; zc->recv_skip_hint = mappable_offset;
}
zc->recv_skip_hint -= remaining;
break; break;
} }
pages[pg_idx] = skb_frag_page(frags); pages[pg_idx] = skb_frag_page(frags);