| Message ID | 5cdb1f50f2e9dc80dbf86cf8667056eacfd36a09.1683564754.git.christophe.jaillet@wanadoo.fr (mailing list archive) |
|---|---|
| State | Awaiting Upstream |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net-next] netfilter: Reorder fields in 'struct nf_conntrack_expect' | expand |
On Mon, May 08, 2023 at 06:53:14PM +0200, Christophe JAILLET wrote: > Group some variables based on their sizes to reduce holes. > On x86_64, this shrinks the size of 'struct nf_conntrack_expect' from 264 > to 256 bytes. > > This structure deserve a dedicated cache, so reducing its size looks nice. > > Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Thanks, this much nicer to me. I slightly concerned that there may be implications for fields that were on the same cacheline now being on different cachelines. But only very slightly. Reviewed-by: Simon Horman <simon.horman@corigine.com> > --- > Using pahole > > Before: > ====== > struct nf_conntrack_expect { > struct hlist_node lnode; /* 0 16 */ > struct hlist_node hnode; /* 16 16 */ > struct nf_conntrack_tuple tuple; /* 32 40 */ > /* --- cacheline 1 boundary (64 bytes) was 8 bytes ago --- */ > struct nf_conntrack_tuple_mask mask; /* 72 20 */ > > /* XXX 4 bytes hole, try to pack */ > > void (*expectfn)(struct nf_conn *, struct nf_conntrack_expect *); /* 96 8 */ > struct nf_conntrack_helper * helper; /* 104 8 */ > struct nf_conn * master; /* 112 8 */ > struct timer_list timeout; /* 120 88 */ > /* --- cacheline 3 boundary (192 bytes) was 16 bytes ago --- */ > refcount_t use; /* 208 4 */ > unsigned int flags; /* 212 4 */ > unsigned int class; /* 216 4 */ > union nf_inet_addr saved_addr; /* 220 16 */ > union nf_conntrack_man_proto saved_proto; /* 236 2 */ > > /* XXX 2 bytes hole, try to pack */ > > enum ip_conntrack_dir dir; /* 240 4 */ > > /* XXX 4 bytes hole, try to pack */ > > struct callback_head rcu __attribute__((__aligned__(8))); /* 248 16 */ > > /* size: 264, cachelines: 5, members: 15 */ > /* sum members: 254, holes: 3, sum holes: 10 */ > /* forced alignments: 1, forced holes: 1, sum forced holes: 4 */ > /* last cacheline: 8 bytes */ > } __attribute__((__aligned__(8))); > > > After: > ===== > struct nf_conntrack_expect { > struct hlist_node lnode; /* 0 16 */ > struct hlist_node hnode; /* 16 16 */ > struct nf_conntrack_tuple tuple; /* 32 40 */ > /* --- cacheline 1 boundary (64 bytes) was 8 bytes ago --- */ > struct nf_conntrack_tuple_mask mask; /* 72 20 */ > refcount_t use; /* 92 4 */ > unsigned int flags; /* 96 4 */ > unsigned int class; /* 100 4 */ > void (*expectfn)(struct nf_conn *, struct nf_conntrack_expect *); /* 104 8 */ > struct nf_conntrack_helper * helper; /* 112 8 */ > struct nf_conn * master; /* 120 8 */ > /* --- cacheline 2 boundary (128 bytes) --- */ > struct timer_list timeout; /* 128 88 */ > /* --- cacheline 3 boundary (192 bytes) was 24 bytes ago --- */ > union nf_inet_addr saved_addr; /* 216 16 */ > union nf_conntrack_man_proto saved_proto; /* 232 2 */ > > /* XXX 2 bytes hole, try to pack */ > > enum ip_conntrack_dir dir; /* 236 4 */ > struct callback_head rcu __attribute__((__aligned__(8))); /* 240 16 */ > > /* size: 256, cachelines: 4, members: 15 */ > /* sum members: 254, holes: 1, sum holes: 2 */ > /* forced alignments: 1 */ > } __attribute__((__aligned__(8))); > --- > include/net/netfilter/nf_conntrack_expect.h | 18 +++++++++--------- > 1 file changed, 9 insertions(+), 9 deletions(-) > > diff --git a/include/net/netfilter/nf_conntrack_expect.h b/include/net/netfilter/nf_conntrack_expect.h > index 0855b60fba17..cf0d81be5a96 100644 > --- a/include/net/netfilter/nf_conntrack_expect.h > +++ b/include/net/netfilter/nf_conntrack_expect.h > @@ -26,6 +26,15 @@ struct nf_conntrack_expect { > struct nf_conntrack_tuple tuple; > struct nf_conntrack_tuple_mask mask; > > + /* Usage count. */ > + refcount_t use; > + > + /* Flags */ > + unsigned int flags; > + > + /* Expectation class */ > + unsigned int class; > + > /* Function to call after setup and insertion */ > void (*expectfn)(struct nf_conn *new, > struct nf_conntrack_expect *this); > @@ -39,15 +48,6 @@ struct nf_conntrack_expect { > /* Timer function; deletes the expectation. */ > struct timer_list timeout; > > - /* Usage count. */ > - refcount_t use; > - > - /* Flags */ > - unsigned int flags; > - > - /* Expectation class */ > - unsigned int class; > - > #if IS_ENABLED(CONFIG_NF_NAT) > union nf_inet_addr saved_addr; > /* This is the original per-proto part, used to map the > -- > 2.34.1 > >
diff --git a/include/net/netfilter/nf_conntrack_expect.h b/include/net/netfilter/nf_conntrack_expect.h index 0855b60fba17..cf0d81be5a96 100644 --- a/include/net/netfilter/nf_conntrack_expect.h +++ b/include/net/netfilter/nf_conntrack_expect.h @@ -26,6 +26,15 @@ struct nf_conntrack_expect { struct nf_conntrack_tuple tuple; struct nf_conntrack_tuple_mask mask; + /* Usage count. */ + refcount_t use; + + /* Flags */ + unsigned int flags; + + /* Expectation class */ + unsigned int class; + /* Function to call after setup and insertion */ void (*expectfn)(struct nf_conn *new, struct nf_conntrack_expect *this); @@ -39,15 +48,6 @@ struct nf_conntrack_expect { /* Timer function; deletes the expectation. */ struct timer_list timeout; - /* Usage count. */ - refcount_t use; - - /* Flags */ - unsigned int flags; - - /* Expectation class */ - unsigned int class; - #if IS_ENABLED(CONFIG_NF_NAT) union nf_inet_addr saved_addr; /* This is the original per-proto part, used to map the
Group some variables based on their sizes to reduce holes. On x86_64, this shrinks the size of 'struct nf_conntrack_expect' from 264 to 256 bytes. This structure deserve a dedicated cache, so reducing its size looks nice. Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> --- Using pahole Before: ====== struct nf_conntrack_expect { struct hlist_node lnode; /* 0 16 */ struct hlist_node hnode; /* 16 16 */ struct nf_conntrack_tuple tuple; /* 32 40 */ /* --- cacheline 1 boundary (64 bytes) was 8 bytes ago --- */ struct nf_conntrack_tuple_mask mask; /* 72 20 */ /* XXX 4 bytes hole, try to pack */ void (*expectfn)(struct nf_conn *, struct nf_conntrack_expect *); /* 96 8 */ struct nf_conntrack_helper * helper; /* 104 8 */ struct nf_conn * master; /* 112 8 */ struct timer_list timeout; /* 120 88 */ /* --- cacheline 3 boundary (192 bytes) was 16 bytes ago --- */ refcount_t use; /* 208 4 */ unsigned int flags; /* 212 4 */ unsigned int class; /* 216 4 */ union nf_inet_addr saved_addr; /* 220 16 */ union nf_conntrack_man_proto saved_proto; /* 236 2 */ /* XXX 2 bytes hole, try to pack */ enum ip_conntrack_dir dir; /* 240 4 */ /* XXX 4 bytes hole, try to pack */ struct callback_head rcu __attribute__((__aligned__(8))); /* 248 16 */ /* size: 264, cachelines: 5, members: 15 */ /* sum members: 254, holes: 3, sum holes: 10 */ /* forced alignments: 1, forced holes: 1, sum forced holes: 4 */ /* last cacheline: 8 bytes */ } __attribute__((__aligned__(8))); After: ===== struct nf_conntrack_expect { struct hlist_node lnode; /* 0 16 */ struct hlist_node hnode; /* 16 16 */ struct nf_conntrack_tuple tuple; /* 32 40 */ /* --- cacheline 1 boundary (64 bytes) was 8 bytes ago --- */ struct nf_conntrack_tuple_mask mask; /* 72 20 */ refcount_t use; /* 92 4 */ unsigned int flags; /* 96 4 */ unsigned int class; /* 100 4 */ void (*expectfn)(struct nf_conn *, struct nf_conntrack_expect *); /* 104 8 */ struct nf_conntrack_helper * helper; /* 112 8 */ struct nf_conn * master; /* 120 8 */ /* --- cacheline 2 boundary (128 bytes) --- */ struct timer_list timeout; /* 128 88 */ /* --- cacheline 3 boundary (192 bytes) was 24 bytes ago --- */ union nf_inet_addr saved_addr; /* 216 16 */ union nf_conntrack_man_proto saved_proto; /* 232 2 */ /* XXX 2 bytes hole, try to pack */ enum ip_conntrack_dir dir; /* 236 4 */ struct callback_head rcu __attribute__((__aligned__(8))); /* 240 16 */ /* size: 256, cachelines: 4, members: 15 */ /* sum members: 254, holes: 1, sum holes: 2 */ /* forced alignments: 1 */ } __attribute__((__aligned__(8))); --- include/net/netfilter/nf_conntrack_expect.h | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-)