On Fri, 2012-09-28 at 11:43 +0800, Zhenzhong Duan wrote: > On 2012-09-27 19:35, Paul Bolle wrote: > > I think setting pages_to_unuse to zero here is not needed. It is > > initiated to zero in frontswap_shrink() and hasn't been touched since. > > See my patch at https://lkml.org/lkml/2012/9/27/250. > Yes, it's unneeded. But I didn't see warning as you said in above link > when run 'make V=1 mm/frontswap.o'. Not even before applying your patch? Anyhow, after applying your patch the warnings gone here too. > >> - return 0; > >> + return 1; > >> } > >> total_pages_to_unuse = total_pages - target_pages; > >> return __frontswap_unuse_pages(total_pages_to_unuse, pages_to_unuse, type); > >> @@ -302,7 +307,7 @@ void frontswap_shrink(unsigned long target_pages) > >> spin_lock(&swap_lock); > >> ret = __frontswap_shrink(target_pages,&pages_to_unuse,&type); > >> spin_unlock(&swap_lock); > >> - if (ret == 0&& pages_to_unuse) > >> + if (ret == 0) > >> try_to_unuse(type, true, pages_to_unuse); > >> return; > >> } > > > > Are you sure pages_to_unuse won't be zero here? I've stared quite a bit > > at __frontswap_unuse_pages() and it's not obvious pages_to_unuse (there > > also called unused) will never be zero when that function returns zero. > pages_to_unuse==0 means all pages need to be unused. Ah, now I see. I was focusing on changing the code as little as possible and didn't realize that you actually wanted to change behavior here. Looking at it again this change makes sense (though I hardly understand frontswap, so I can't properly evaluate it). Anyhow, as I said, your patch also does what I care about - silence a warning - so we might as well forget about my patch. Thanks, Paul Bolle -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>