From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f70.google.com (mail-wm0-f70.google.com [74.125.82.70]) by kanga.kvack.org (Postfix) with ESMTP id 533B36B025F for ; Tue, 9 Aug 2016 11:52:19 -0400 (EDT) Received: by mail-wm0-f70.google.com with SMTP id u81so26341890wmu.3 for ; Tue, 09 Aug 2016 08:52:19 -0700 (PDT) Received: from fireflyinternet.com (mail.fireflyinternet.com. [109.228.58.192]) by mx.google.com with ESMTPS id s17si3647908wmb.62.2016.08.09.08.52.17 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 09 Aug 2016 08:52:18 -0700 (PDT) Date: Tue, 9 Aug 2016 16:52:13 +0100 From: Chris Wilson Subject: Re: [PATCH v2] mm/slub: Run free_partial() outside of the kmem_cache_node->list_lock Message-ID: <20160809155213.GI21147@nuc-i3427.alporthouse.com> References: <20160809151743.GF1983@esperanza> <1470756466-12493-1-git-send-email-chris@chris-wilson.co.uk> <20160809154539.GG1983@esperanza> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160809154539.GG1983@esperanza> Sender: owner-linux-mm@kvack.org List-ID: To: Vladimir Davydov Cc: linux-kernel@vger.kernel.org, Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Dmitry Safonov , Daniel Vetter , Dave Gordon , linux-mm@kvack.org On Tue, Aug 09, 2016 at 06:45:39PM +0300, Vladimir Davydov wrote: > On Tue, Aug 09, 2016 at 04:27:46PM +0100, Chris Wilson wrote: > ... > > diff --git a/mm/slub.c b/mm/slub.c > > index 825ff45..58f0eb6 100644 > > --- a/mm/slub.c > > +++ b/mm/slub.c > > @@ -3479,6 +3479,7 @@ static void list_slab_objects(struct kmem_cache *s, struct page *page, > > */ > > static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n) > > { > > + LIST_HEAD(partial_list); > > nit: slabs added to this list are not partially used - they are free, so > let's call it 'free_slabs' or 'discard_list' or just 'discard', please Ok. > > struct page *page, *h; > > > > BUG_ON(irqs_disabled()); > > @@ -3486,13 +3487,16 @@ static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n) > > list_for_each_entry_safe(page, h, &n->partial, lru) { > > if (!page->inuse) { > > remove_partial(n, page); > > - discard_slab(s, page); > > + list_add(&page->lru, &partial_list); > > If there are objects left in the cache on destruction, the cache won't > be destroyed. Instead it will be left on the slab_list and can get > reused later. So we should use list_move() here to always leave > n->partial in a consistent state, even in case of a leak. Since remove_partial() does an unconditional list_del(), I presume you want to perform the list_move() even if we hit the error path, right? i.e. list_for_each_entry_safe(page, h, &n->partial, lru) { if (!page->inuse) { remove_partial(n, page); - list_add(&page->lru, &partial_list); } else { list_slab_objects(s, page, "Objects remaining in %s on __kmem_cache_shutdown()"); } + list_move(&page->lru, &discard); -Chris -- Chris Wilson, Intel Open Source Technology Centre -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org