Messages in this thread | | | Date | Fri, 1 May 2009 11:13:17 +0900 | Subject | Re: [PATCH] blktrace: swap arg name "from" and "to" of blk_add_trace_remap | From | KOSAKI Motohiro <> |
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> I believe this may be more messed up than you believe: Consider the last > function: blk_log_remap. Notice how you are printing the /device/ and > /sector_from/ as one pair. Isn't that confusing too: wouldn't one expect > /device_from/ and /sector_from/ to be paired up? > > I ran into this problem a long time ago - hence the current code in > blkparse contains: > > if (act[0] == 'A') { /* Remap */ > get_pdu_remap(t, &r); > t->device = r.device_from; > } > > Which puts the device_from out at the beginning of the line, and then > the 'device' + 'sector' (== 'sector_from') out at the end of the line. > (Which, of course, is all confusing.)
Good viewpoint! Currently, 99% blktrace user use blktrace and blkparse command, not ftrace framework. So, ABI changing is proper way?
I'd like to hear Jens and Li opinion.
> To really fix this, I think one needs to: > > (a) adjust the kernel to make "r.device_from" and "r.sector_from" refer > to the same part of the trace, and the "r.device" and "t->sector" refer > to the other part of the trace. > > (b) fix blkparse (& btt & ...) to do the same thing - not make > adjustments for the stupid naming... > > If we leave the kernel->user space ABI alone: > > first u32: device mapped /from/ > second u32: device mapped /to/ > u64: sector mapped from > > We can then change the names. I've followed this e-mail up with a pair > of kernel-side patches and will submit user side fixes for blkptrace later. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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