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Date: Fri, 20 Apr 2018 06:41:36 -0700
From: Matthew Wilcox <willy@infradead.org>
Subject: Re: [PATCH] kvmalloc: always use vmalloc if CONFIG_DEBUG_VM
Message-ID: <20180420134136.GD10788@bombadil.infradead.org>
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To: Michal Hocko <mhocko@kernel.org>
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>

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?