Messages in this thread | | | Date | Fri, 13 Nov 2015 10:26:42 -0500 (EST) | From | Thomas Gleixner <> | Subject | Re: [PATCH] clocksource/drivers/tango-xtal: Replace code by clocksource_mmio_init |
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On Fri, 13 Nov 2015, Marc Gonzalez wrote: > On 13/11/2015 15:16, Daniel Lezcano wrote: > > For example: > > > > struct clockcommon { > > u32 mult; > > u32 shift; > > int rating; > > void __iomem *base; > > char *name; > > int irq; > > }; > > > > struct clocksource { > > struct clockcommon common; /* MUST be the first field */ > > cycle_t (*read)(struct clocksource *cs); > > cycle_t mask; > > ... > > }; > > According to my notes, commit 369db4c952 grouped hot-path data > into a single cache line (hence ____cacheline_aligned). > > (AFAIR, ARMv7 ARCH_MULTIPLATFORM assumes CACHE_LINE=64) > > Not sure how to make the two concepts (common base struct and > grouping hot data) play nicely, without wasting a lot of space > on padding.
It wont play well. We are not going to change the layout of struct clocksource because it will hurt the sane use cases for no reason.
Thanks,
tglx
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