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| author |   Michael Neuling <mikey@neuling.org> | 2015-12-11 09:34:42 +1100 |
|---|---|---|
| committer |   Michael Ellerman <mpe@ellerman.id.au> | 2015-12-27 19:12:14 +1100 |
| commit | 2fc251a8dda56b71ec491bee4c6897e3e12c0739 (patch) | |
| tree | c851eab2210153cfc4e706b2680ef64ee2329dce /arch/powerpc/mm/hash_utils_64.c | |
| parent | powerpc: Add function to copy mm_context_t to the paca (diff) | |
| download | linux-dev-2fc251a8dda56b71ec491bee4c6897e3e12c0739.tar.xz linux-dev-2fc251a8dda56b71ec491bee4c6897e3e12c0739.zip | |
powerpc: Copy only required pieces of the mm_context_t to the paca
Currently we copy the whole mm_context_t to the paca but only access a
few bits of it. This is wasteful of space paca and also takes quite
some time in the hot path of context switching.
This patch pulls in only the required bits from the mm_context_t to
the paca and on context switch, copies only those.
Benchmarking this (On top of Anton's recent MSR context switching
changes [1]) using processes and yield shows an improvement of almost
3% on POWER8:
http://ozlabs.org/~anton/junkcode/context_switch2.c
./context_switch2 --test=yield --process 0 0
1. https://lists.ozlabs.org/pipermail/linuxppc-dev/2015-October/135700.html
Signed-off-by: Michael Neuling <mikey@neuling.org>
[mpe: Rename paca fields to be mm_ctx_foo rather than context_foo]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/mm/hash_utils_64.c')
| -rw-r--r-- | arch/powerpc/mm/hash_utils_64.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c index 03279eac0957..db744576d730 100644 --- a/arch/powerpc/mm/hash_utils_64.c +++ b/arch/powerpc/mm/hash_utils_64.c @@ -853,11 +853,11 @@ static unsigned int get_paca_psize(unsigned long addr) unsigned long index, mask_index; if (addr < SLICE_LOW_TOP) { - lpsizes = get_paca()->context.low_slices_psize; + lpsizes = get_paca()->mm_ctx_low_slices_psize; index = GET_LOW_SLICE_INDEX(addr); return (lpsizes >> (index * 4)) & 0xF; } - hpsizes = get_paca()->context.high_slices_psize; + hpsizes = get_paca()->mm_ctx_high_slices_psize; index = GET_HIGH_SLICE_INDEX(addr); mask_index = index & 0x1; return (hpsizes[index >> 1] >> (mask_index * 4)) & 0xF; |