- do no extra readahead when (readahead_ratio == 1) - define readahead_hit_rate inside CONFIG_ADAPTIVE_READAHEAD ifdefs Signed-off-by: Fengguang Wu --- --- linux-2.6.19-rc6-mm1.orig/include/linux/mm.h +++ linux-2.6.19-rc6-mm1/include/linux/mm.h @@ -1074,7 +1074,7 @@ extern int readahead_ratio; static inline int prefer_adaptive_readahead(void) { - return readahead_ratio > 1; + return readahead_ratio != 1; } /* Do stack extension */ --- linux-2.6.19-rc6-mm1.orig/Documentation/sysctl/vm.txt +++ linux-2.6.19-rc6-mm1/Documentation/sysctl/vm.txt @@ -234,7 +234,7 @@ plenty of memory(>>2MB per reader), a bi readahead_ratio also selects the readahead logic: VALUE CODE PATH ------------------------------------------- - 0 disable readahead totally + 0 read as is, no extra readahead 1 select the stock readahead logic 2-100 select the adaptive readahead logic --- linux-2.6.19-rc6-mm1.orig/mm/readahead.c +++ linux-2.6.19-rc6-mm1/mm/readahead.c @@ -40,10 +40,10 @@ /* Set read-ahead size to ##% of the thrashing-threshold. */ int readahead_ratio = 50; EXPORT_SYMBOL_GPL(readahead_ratio); -#endif /* Readahead as long as cache hit ratio keeps above 1/##. */ int readahead_hit_rate = 0; +#endif /* CONFIG_ADAPTIVE_READAHEAD */ /* * Detailed classification of read-ahead behaviors. -- - 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/