On Fri, Mar 22, 2013 at 08:33:19PM +0200, Octavian Purdila wrote: > When using a large number of threads performing AIO operations the > IOCTX list may get a significant number of entries which will cause > significant overhead. For example, when running this fio script: Indeed. But you also need to consider the impact this change has on the typical case of only having one ctx in the mm. Please include measurements of that case in the commit message. > --- a/arch/s390/mm/pgtable.c > +++ b/arch/s390/mm/pgtable.c > @@ -831,7 +831,7 @@ int s390_enable_sie(void) > task_lock(tsk); > if (!tsk->mm || atomic_read(&tsk->mm->mm_users) > 1 || > #ifdef CONFIG_AIO > - !hlist_empty(&tsk->mm->ioctx_list) || > + tsk->mm->ioctx_rtree.rnode || > #endif Boy, what a curious thing. I wonder if this is still needed if we're no longer storing the mm in the ctx after retry support is removed. > + err = radix_tree_insert(&mm->ioctx_rtree, ctx->user_id, ctx); Hmm. Is there anything stopping an exceptionally jerky app from racing io_setup() and munmap() and having two contexts be mapped to the same address and get the same user_id? I guess this would just return -EEXIST, then, not do anything terrible. I guess that's OK? > + idx, sizeof(ctx)/sizeof(void *)); ARRAY_SIZE(ctx) And why bother tracking the starting idx? If you're completely draining it simply always start from 0? - z -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
