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| author | Anton Blanchard <anton@samba.org> | 2010-01-31 20:32:51 +0000 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2010-02-17 14:02:48 +1100 |
| commit | fda9d86100e0b412d0c8a16abe0651c8c8e39e81 (patch) | |
| tree | dccc2fce96c47f35e8f18c282a842fa8113a2e2d /arch/powerpc/platforms/pseries | |
| parent | 8c007bfdf1bab536f824d91fccc76596c18aba78 (diff) | |
| download | blackbird-obmc-linux-fda9d86100e0b412d0c8a16abe0651c8c8e39e81.tar.gz blackbird-obmc-linux-fda9d86100e0b412d0c8a16abe0651c8c8e39e81.zip | |
powerpc: Reduce footprint of xics_ipi_struct
Right now we allocate a cacheline sized NR_CPUS array for xics IPI
communication. Use DECLARE_PER_CPU_SHARED_ALIGNED to put it in percpu
data in its own cacheline since it is written to by other cpus.
On a kernel with NR_CPUS=1024, this saves quite a lot of memory:
text data bss dec hex filename
8767779 2944260 1505724 13217763 c9afe3 vmlinux.irq_cpustat
8767555 2813444 1505724 13086723 c7b003 vmlinux.xics
A saving of around 128kB.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/platforms/pseries')
| -rw-r--r-- | arch/powerpc/platforms/pseries/xics.c | 26 |
1 files changed, 11 insertions, 15 deletions
diff --git a/arch/powerpc/platforms/pseries/xics.c b/arch/powerpc/platforms/pseries/xics.c index 63eaa8a220c0..41374e830eb1 100644 --- a/arch/powerpc/platforms/pseries/xics.c +++ b/arch/powerpc/platforms/pseries/xics.c @@ -510,15 +510,13 @@ static void __init xics_init_host(void) /* * XICS only has a single IPI, so encode the messages per CPU */ -struct xics_ipi_struct { - unsigned long value; - } ____cacheline_aligned; - -static struct xics_ipi_struct xics_ipi_message[NR_CPUS] __cacheline_aligned; +static DEFINE_PER_CPU_SHARED_ALIGNED(unsigned long, xics_ipi_message); static inline void smp_xics_do_message(int cpu, int msg) { - set_bit(msg, &xics_ipi_message[cpu].value); + unsigned long *tgt = &per_cpu(xics_ipi_message, cpu); + + set_bit(msg, tgt); mb(); if (firmware_has_feature(FW_FEATURE_LPAR)) lpar_qirr_info(cpu, IPI_PRIORITY); @@ -544,25 +542,23 @@ void smp_xics_message_pass(int target, int msg) static irqreturn_t xics_ipi_dispatch(int cpu) { + unsigned long *tgt = &per_cpu(xics_ipi_message, cpu); + WARN_ON(cpu_is_offline(cpu)); mb(); /* order mmio clearing qirr */ - while (xics_ipi_message[cpu].value) { - if (test_and_clear_bit(PPC_MSG_CALL_FUNCTION, - &xics_ipi_message[cpu].value)) { + while (*tgt) { + if (test_and_clear_bit(PPC_MSG_CALL_FUNCTION, tgt)) { smp_message_recv(PPC_MSG_CALL_FUNCTION); } - if (test_and_clear_bit(PPC_MSG_RESCHEDULE, - &xics_ipi_message[cpu].value)) { + if (test_and_clear_bit(PPC_MSG_RESCHEDULE, tgt)) { smp_message_recv(PPC_MSG_RESCHEDULE); } - if (test_and_clear_bit(PPC_MSG_CALL_FUNC_SINGLE, - &xics_ipi_message[cpu].value)) { + if (test_and_clear_bit(PPC_MSG_CALL_FUNC_SINGLE, tgt)) { smp_message_recv(PPC_MSG_CALL_FUNC_SINGLE); } #if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC) - if (test_and_clear_bit(PPC_MSG_DEBUGGER_BREAK, - &xics_ipi_message[cpu].value)) { + if (test_and_clear_bit(PPC_MSG_DEBUGGER_BREAK, tgt)) { smp_message_recv(PPC_MSG_DEBUGGER_BREAK); } #endif |
