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Date:   Wed, 19 Jan 2022 13:22:04 +0000
From:   Matthew Wilcox <willy@infradead.org>
To:     Kefeng Wang <wangkefeng.wang@huawei.com>
Cc:     Nicholas Piggin <npiggin@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Jonathan Corbet <corbet@lwn.net>,
        linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        linuxppc-dev@lists.ozlabs.org, x86@kernel.org,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Borislav Petkov <bp@alien8.de>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Christophe Leroy <christophe.leroy@csgroup.eu>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Paul Mackerras <paulus@samba.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Will Deacon <will@kernel.org>
Subject: Re: [PATCH v2 1/3] mm: vmalloc: Let user to control huge vmalloc
 default behavior
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References: <20211227145903.187152-1-wangkefeng.wang@huawei.com>
 <20211227145903.187152-2-wangkefeng.wang@huawei.com>
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 <f0dd59eb-6eb8-5b60-508d-7f4022f655ec@huawei.com>
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On Wed, Jan 19, 2022 at 08:57:58PM +0800, Kefeng Wang wrote:
> Only parts of our products wants this feature,  we add some interfaces which
> only
> 
> alloc hugevmalloc for them, eg,
> vmap_hugepage/vmalloc_hugepage/remap_vmalloc_hugepage_range..
> 
> for our products, but it's not the choice of most products, also add
> nohugevmalloc
> 
> for most products is expensive, so this is the reason for adding the patch.
> 
> more config/cmdline are more flexible for test/products，

But why do only some products want it?  What goes wrong if all products
enable it?  Features should be auto-tuning, not relying on admins to
understand them.