Messages in this thread | | | Subject | Re: [tip:x86/mm] percpu: Introduce a read-mostly percpu API | From | Eric Dumazet <> | Date | Thu, 21 Oct 2010 07:33:50 +0200 |
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Le jeudi 21 octobre 2010 à 09:38 +0800, Shaohua Li a écrit : > Hi hpa, > On Thu, Oct 21, 2010 at 07:06:59AM +0800, tip-bot for Shaohua Li wrote: > > [ hpa: moved it *after* the page-aligned section, for obvious > > reasons. ] > move it after page-aligned section can't guarantee to avoid cache false sharing. > we need: > . = ALIGN(CACHE_LINE_SIZE); > *(.data..percpu..readmostly) > . = ALIGN(CACHE_LINE_SIZE); > To make sure before/after readmostly section doesn't share cache line with > others. The headcache is some arch need L1_CACHE_SIZE and others need > (1 << INTERNODE_CACHE_SHIFT). We need change all ARCHs to make this happen.
Really, readmostly percpu variables dont need INTERNODE_CACHE_SHIFT, as this is read mostly, and per cpu vars ;)
Just use L1_CACHE_BYTES
*(.data..percpu..first) \ *(.data..percpu..page_aligned) \ + . = ALIGN(L1_CACHE_BYTES \ + *(.data..percpu..readmostly) \ + . = ALIGN(L1_CACHE_BYTES \ *(.data..percpu) \
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