From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031476AbdAFWPO (ORCPT ); Fri, 6 Jan 2017 17:15:14 -0500 Received: from mail-pf0-f195.google.com ([209.85.192.195]:34605 "EHLO mail-pf0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S939829AbdAFWOv (ORCPT ); Fri, 6 Jan 2017 17:14:51 -0500 Message-ID: <1483740889.9712.44.camel@edumazet-glaptop3.roam.corp.google.com> Subject: Re: weird allocation pattern in alloc_ila_locks From: Eric Dumazet To: Michal Hocko Cc: Tom Herbert , linux-mm@kvack.org, LKML , edumazet@google.com Date: Fri, 06 Jan 2017 14:14:49 -0800 In-Reply-To: <20170106121642.GJ5556@dhcp22.suse.cz> References: <20170106095115.GG5556@dhcp22.suse.cz> <20170106100433.GH5556@dhcp22.suse.cz> <20170106121642.GJ5556@dhcp22.suse.cz> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.4-0ubuntu2 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2017-01-06 at 13:16 +0100, Michal Hocko wrote: > I was thinking about the rhashtable which was the source of the c&p and > it can be simplified as well. > --- > From 555543604f5f020284ea85d928d52f6a55fde7ca Mon Sep 17 00:00:00 2001 > From: Michal Hocko > Date: Fri, 6 Jan 2017 13:12:31 +0100 > Subject: [PATCH] rhashtable: simplify a strange allocation pattern > > alloc_bucket_locks allocation pattern is quite unusual. We are > preferring vmalloc when CONFIG_NUMA is enabled which doesn't make much > sense because there is no special NUMA locality handled in that code > path. Let's just simplify the code and use kvmalloc helper, which is a > transparent way to use kmalloc with vmalloc fallback, if the caller > is allowed to block and use the flag otherwise. > > Signed-off-by: Michal Hocko > --- > lib/rhashtable.c | 13 +++---------- > 1 file changed, 3 insertions(+), 10 deletions(-) > > diff --git a/lib/rhashtable.c b/lib/rhashtable.c > index 32d0ad058380..4d3886b6ab7d 100644 > --- a/lib/rhashtable.c > +++ b/lib/rhashtable.c > @@ -77,16 +77,9 @@ static int alloc_bucket_locks(struct rhashtable *ht, struct bucket_table *tbl, > size = min_t(unsigned int, size, tbl->size >> 1); > > if (sizeof(spinlock_t) != 0) { > - tbl->locks = NULL; > -#ifdef CONFIG_NUMA > - if (size * sizeof(spinlock_t) > PAGE_SIZE && > - gfp == GFP_KERNEL) > - tbl->locks = vmalloc(size * sizeof(spinlock_t)); > -#endif > - if (gfp != GFP_KERNEL) > - gfp |= __GFP_NOWARN | __GFP_NORETRY; > - > - if (!tbl->locks) > + if (gfpflags_allow_blocking(gfp_)) > + tbl->locks = kvmalloc(size * sizeof(spinlock_t), gfp); > + else > tbl->locks = kmalloc_array(size, sizeof(spinlock_t), I believe the intent was to get NUMA spreading, a bit like what we have in alloc_large_system_hash() when hashdist == HASHDIST_DEFAULT For hash tables that are not attached to a single NUMA node, this might make sense.