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Reorder the fields to save 8 bytes. > > Statistics before: > > $ pahole --class_name=raw_sock net/can/raw.o > struct raw_sock { > struct sock sk __attribute__((__aligned__(8))); /* 0 776 */ > > /* XXX last struct has 1 bit hole */ > > /* --- cacheline 12 boundary (768 bytes) was 8 bytes ago --- */ > int bound; /* 776 4 */ > int ifindex; /* 780 4 */ > struct net_device * dev; /* 784 8 */ > netdevice_tracker dev_tracker; /* 792 0 */ > struct list_head notifier; /* 792 16 */ > unsigned int loopback:1; /* 808: 0 4 */ > unsigned int recv_own_msgs:1; /* 808: 1 4 */ > unsigned int fd_frames:1; /* 808: 2 4 */ > unsigned int xl_frames:1; /* 808: 3 4 */ > > /* XXX 4 bits hole, try to pack */ > /* Bitfield combined with next fields */ > > struct can_raw_vcid_options raw_vcid_opts; /* 809 4 */ > > /* XXX 3 bytes hole, try to pack */ > > canid_t tx_vcid_shifted; /* 816 4 */ > canid_t rx_vcid_shifted; /* 820 4 */ > canid_t rx_vcid_mask_shifted; /* 824 4 */ > int join_filters; /* 828 4 */ > /* --- cacheline 13 boundary (832 bytes) --- */ > int count; /* 832 4 */ > struct can_filter dfilter; /* 836 8 */ > > /* XXX 4 bytes hole, try to pack */ > > struct can_filter * filter; /* 848 8 */ > can_err_mask_t err_mask; /* 856 4 */ > > /* XXX 4 bytes hole, try to pack */ > > struct uniqframe * uniq; /* 864 8 */ > > /* size: 872, cachelines: 14, members: 20 */ > /* sum members: 860, holes: 3, sum holes: 11 */ > /* sum bitfield members: 4 bits, bit holes: 1, sum bit holes: 4 bits */ > /* member types with bit holes: 1, total: 1 */ > /* forced alignments: 1 */ > /* last cacheline: 40 bytes */ > } __attribute__((__aligned__(8))); > > ...and after: > > $ pahole --class_name=raw_sock net/can/raw.o > struct raw_sock { > struct sock sk __attribute__((__aligned__(8))); /* 0 776 */ > > /* XXX last struct has 1 bit hole */ > > /* --- cacheline 12 boundary (768 bytes) was 8 bytes ago --- */ > int bound; /* 776 4 */ > int ifindex; /* 780 4 */ > struct net_device * dev; /* 784 8 */ > netdevice_tracker dev_tracker; /* 792 0 */ > struct list_head notifier; /* 792 16 */ > struct can_raw_vcid_options raw_vcid_opts; /* 808 4 */ > unsigned int loopback:1; /* 812: 0 4 */ > unsigned int recv_own_msgs:1; /* 812: 1 4 */ > unsigned int fd_frames:1; /* 812: 2 4 */ > unsigned int xl_frames:1; /* 812: 3 4 */ > > /* XXX 28 bits hole, try to pack */ > > canid_t tx_vcid_shifted; /* 816 4 */ > canid_t rx_vcid_shifted; /* 820 4 */ > canid_t rx_vcid_mask_shifted; /* 824 4 */ > can_err_mask_t err_mask; /* 828 4 */ > /* --- cacheline 13 boundary (832 bytes) --- */ > int join_filters; /* 832 4 */ > int count; /* 836 4 */ > struct can_filter dfilter; /* 840 8 */ > struct can_filter * filter; /* 848 8 */ > struct uniqframe * uniq; /* 856 8 */ > > /* size: 864, cachelines: 14, members: 20 */ > /* sum members: 860 */ > /* sum bitfield members: 4 bits, bit holes: 1, sum bit holes: 28 bits */ > /* member types with bit holes: 1, total: 1 */ > /* forced alignments: 1 */ > /* last cacheline: 32 bytes */ > } __attribute__((__aligned__(8))); > > Signed-off-by: Vincent Mailhol Acked-by: Oliver Hartkopp > --- > net/can/raw.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/net/can/raw.c b/net/can/raw.c > index cec580ecd58e36931d1be05716e6beb9c93aa271..81f5de63bcfaacf3f51670159fb3d1d7d1fc6020 100644 > --- a/net/can/raw.c > +++ b/net/can/raw.c > @@ -87,19 +87,19 @@ struct raw_sock { > struct net_device *dev; > netdevice_tracker dev_tracker; > struct list_head notifier; > + struct can_raw_vcid_options raw_vcid_opts; > unsigned int loopback:1; > unsigned int recv_own_msgs:1; > unsigned int fd_frames:1; > unsigned int xl_frames:1; > - struct can_raw_vcid_options raw_vcid_opts; > canid_t tx_vcid_shifted; > canid_t rx_vcid_shifted; > canid_t rx_vcid_mask_shifted; > + can_err_mask_t err_mask; > int join_filters; > int count; /* number of active filters */ > struct can_filter dfilter; /* default/single filter */ > struct can_filter *filter; /* pointer to filter(s) */ > - can_err_mask_t err_mask; > struct uniqframe __percpu *uniq; > }; > >