On Tue, Sep 10, 2013 at 4:53 PM, Al Viro <v...@zeniv.linux.org.uk> wrote: > > list_lru_add() can fail if it's already on the list; leaving the counter > alone should've been conditional on that, setting the flag - no. Said > that, it probably should be WARN_ON(!...); this_cpu_inc(); ... |= ...;
That WARN_ON_(!..) might indeed be better (maybe just WARN_ON_ONCE()).. That DCACHE_LRU_LIST bit needs to be coherent with "the dentry->d_lru entry is on _some_ list" (whether it's the dentry one or the shrinker one), so if that list_lru_add() ever fails, that would be a sign of badness. And that whole function is very performance-critical, to the point where we not only don't want to call down to list_lry_add(), we don't even want to touch the d_lru list entry itself to even _look_ if it's empty or not, because that will take a cache miss. Which was obviously the whole reason for that DCACHE_LRU_LIST bit existing... Linus -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/