From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-f69.google.com (mail-ed1-f69.google.com [209.85.208.69]) by kanga.kvack.org (Postfix) with ESMTP id C6CC76B0010 for ; Thu, 1 Nov 2018 06:24:07 -0400 (EDT) Received: by mail-ed1-f69.google.com with SMTP id x1-v6so11855923edh.8 for ; Thu, 01 Nov 2018 03:24:07 -0700 (PDT) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id e14-v6si7907753edc.260.2018.11.01.03.24.06 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 01 Nov 2018 03:24:06 -0700 (PDT) Date: Thu, 1 Nov 2018 11:24:05 +0100 From: Michal Hocko Subject: Re: [PATCH 2] mm/kvmalloc: do not call kmalloc for size > KMALLOC_MAX_SIZE Message-ID: <20181101102405.GE23921@dhcp22.suse.cz> References: <154106356066.887821.4649178319705436373.stgit@buzz> <154106695670.898059.5301435081426064314.stgit@buzz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <154106695670.898059.5301435081426064314.stgit@buzz> Sender: owner-linux-mm@kvack.org List-ID: To: Konstantin Khlebnikov Cc: linux-mm@kvack.org, Andrew Morton , linux-kernel@vger.kernel.org On Thu 01-11-18 13:09:16, Konstantin Khlebnikov wrote: > Allocations over KMALLOC_MAX_SIZE could be served only by vmalloc. I would go on and say that allocations with sizes too large can actually trigger a warning (once you have posted in the previous version outside of the changelog area) because that might be interesting to people - there are deployments to panic on warning and then a warning is much more important. > Signed-off-by: Konstantin Khlebnikov Acked-by: Michal Hocko Thanks! > --- > mm/util.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/mm/util.c b/mm/util.c > index 8bf08b5b5760..f5f04fa22814 100644 > --- a/mm/util.c > +++ b/mm/util.c > @@ -392,6 +392,9 @@ void *kvmalloc_node(size_t size, gfp_t flags, int node) > gfp_t kmalloc_flags = flags; > void *ret; > > + if (size > KMALLOC_MAX_SIZE) > + goto fallback; > + > /* > * vmalloc uses GFP_KERNEL for some internal allocations (e.g page tables) > * so the given set of flags has to be compatible. > @@ -422,6 +425,7 @@ void *kvmalloc_node(size_t size, gfp_t flags, int node) > if (ret || size <= PAGE_SIZE) > return ret; > > +fallback: > return __vmalloc_node_flags_caller(size, node, flags, > __builtin_return_address(0)); > } > -- Michal Hocko SUSE Labs