d430d3d7e6
Introduce: static __always_inline bool static_branch(struct jump_label_key *key); instead of the old JUMP_LABEL(key, label) macro. In this way, jump labels become really easy to use: Define: struct jump_label_key jump_key; Can be used as: if (static_branch(&jump_key)) do unlikely code enable/disale via: jump_label_inc(&jump_key); jump_label_dec(&jump_key); that's it! For the jump labels disabled case, the static_branch() becomes an atomic_read(), and jump_label_inc()/dec() are simply atomic_inc(), atomic_dec() operations. We show testing results for this change below. Thanks to H. Peter Anvin for suggesting the 'static_branch()' construct. Since we now require a 'struct jump_label_key *key', we can store a pointer into the jump table addresses. In this way, we can enable/disable jump labels, in basically constant time. This change allows us to completely remove the previous hashtable scheme. Thanks to Peter Zijlstra for this re-write. Testing: I ran a series of 'tbench 20' runs 5 times (with reboots) for 3 configurations, where tracepoints were disabled. jump label configured in avg: 815.6 jump label *not* configured in (using atomic reads) avg: 800.1 jump label *not* configured in (regular reads) avg: 803.4 Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20110316212947.GA8792@redhat.com> Signed-off-by: Jason Baron <jbaron@redhat.com> Suggested-by: H. Peter Anvin <hpa@linux.intel.com> Tested-by: David Daney <ddaney@caviumnetworks.com> Acked-by: Ralf Baechle <ralf@linux-mips.org> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> |
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.. | ||
alchemy | ||
ar7 | ||
ath79 | ||
bcm47xx | ||
bcm63xx | ||
boot | ||
cavium-octeon | ||
cobalt | ||
configs | ||
dec | ||
emma | ||
fw | ||
include/asm | ||
jazz | ||
jz4740 | ||
kernel | ||
lasat | ||
lib | ||
loongson | ||
math-emu | ||
mipssim | ||
mm | ||
mti-malta | ||
nxp/pnx8550/common | ||
oprofile | ||
pci | ||
pmc-sierra | ||
pnx833x | ||
pnx8550 | ||
power | ||
powertv | ||
rb532 | ||
sgi-ip22 | ||
sgi-ip27 | ||
sgi-ip32 | ||
sibyte | ||
sni | ||
txx9 | ||
vr41xx | ||
wrppmc | ||
Kbuild | ||
Kbuild.platforms | ||
Kconfig | ||
Kconfig.debug | ||
Makefile |