Revert "perf: Fix warning while reading ring buffer headers"
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From: Frederic Weisbecker on 14 May 2010 23:40 On Thu, May 13, 2010 at 04:03:48PM +1000, Ian Munsie wrote: > From: Ian Munsie <imunsie(a)au1.ibm.com> > > This reverts commit d00a47cce569a3e660a8c9de5d57af28d6a9f0f7. > "perf: Fix warning while reading ring buffer headers" > > The reverted patch removed the processing of the header_page, skipping > over it instead on the assumption that perf was not using any of the > data from that header. The patch neglected to remove the header_page_ > variables which were initialised in the removed code, nor did it fix any > code that was using those variables. > > In particular, long_size was set based on one of those variables > (header_page_size_size) to learn the size of a long from the kernel, > which is necessary to correctly print out some of the trace information > in some circumstances. For instance, the size of a long in a 64 bit > kernel would differ from the size of a long in perf if it was compiled > for a 32 bit userspace. Perf trace needs to know the size of a long in > the kernel so that it can print out the correct value without > truncation. I don't understand. In the format file we have the size of the fields beside their type name, so why do we need this? Thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |