From mboxrd@z Thu Jan  1 00:00:00 1970
From: Matthew Wilcox <willy@infradead.org>
Subject: Re: [PATCH] kvmalloc: always use vmalloc if CONFIG_DEBUG_VM
Date: Fri, 20 Apr 2018 06:41:36 -0700
Message-ID: <20180420134136.GD10788@bombadil.infradead.org>
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 <alpine.LRH.2.02.1804181218270.19136@file01.intranet.prod.int.rdu2.redhat.com>
 <20180418.134651.2225112489265654270.davem@davemloft.net>
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 <alpine.LRH.2.02.1804191207380.31175@file01.intranet.prod.int.rdu2.redhat.com>
 <20180420130852.GC16083@dhcp22.suse.cz>
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Cc: Mikulas Patocka <mpatocka@redhat.com>,
        David Miller <davem@davemloft.net>,
        Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
        eric.dumazet@gmail.com, edumazet@google.com,
        bhutchings@solarflare.com, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, mst@redhat.com, jasowang@redhat.com,
        virtualization@lists.linux-foundation.org, dm-devel@redhat.com,
        Vlastimil Babka <vbabka@suse.cz>
To: Michal Hocko <mhocko@kernel.org>
Return-path: <linux-kernel-owner@vger.kernel.org>
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On Fri, Apr 20, 2018 at 03:08:52PM +0200, Michal Hocko wrote:
> > In order to detect these bugs reliably I submit this patch that changes
> > kvmalloc to always use vmalloc if CONFIG_DEBUG_VM is turned on.
> 
> No way. This is just wrong! First of all, you will explode most likely
> on many allocations of small sizes. Second, CONFIG_DEBUG_VM tends to be
> enabled quite often.

I think it'll still suit Mikulas' debugging needs if we always use
vmalloc for sizes above PAGE_SIZE?