Messages in this thread |  | | Date | Tue, 6 Feb 2007 20:31:58 +0200 | From | "saeed bishara" <> | Subject | cache coherecy when working with cpu dcache write allocate |
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Hi, I came across data corruption problem when using xfs, my system is arm 926, the data cache is virtually tagged and virtually indexed and with no hw cache coherency. my CPU features the data cache write allocate-> when doing store, the cache line of the destination address is loaded to data cache. when enabling the write allocate, I got data corruption with the xfs. the scenario is that the xfs allocates large buffer (for reading the log records) using vmalloc, and the low level driver (raid) copies the data to the bio vectors using the linear address, since the write allocate is enabled, the correct data remains on the data cache with the linear address tag, when the IO completes, the xfs access the data with using the vmalloc virtual address, which is different than the kernel linear address, thus it will get a stale data!.
how should I fix this problem? I thought that only the copy/clean_user_pages() functions should be aware to the write allocate.
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