Revision 441c228f817f7597e090d84aca74bdb7c2bd5040 authored by Mel Gorman on 13 December 2014, 00:56:33 UTC, committed by Linus Torvalds on 13 December 2014, 20:42:49 UTC
A random seek IO benchmark appeared to regress because of a change to readahead but the real problem was the benchmark. To ensure the IO request accesssed disk, it used fadvise(FADV_DONTNEED) on a block boundary (512K) but the hint is ignored by the kernel. This is correct but not necessarily obvious behaviour. As much as I dislike comment patches, the explanation for this behaviour predates current git history. Clarify why it behaves like this in case someone "fixes" fadvise or readahead for the wrong reasons. Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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| COPYING | -rw-r--r-- | 18.3 KB |
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| Kbuild | -rw-r--r-- | 2.5 KB |
| Kconfig | -rw-r--r-- | 252 bytes |
| MAINTAINERS | -rw-r--r-- | 290.2 KB |
| Makefile | -rw-r--r-- | 53.2 KB |
| README | -rw-r--r-- | 18.3 KB |
| REPORTING-BUGS | -rw-r--r-- | 7.3 KB |
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