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From: Song Liu <songliubraving@fb.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: Song Liu <song@kernel.org>, bpf <bpf@vger.kernel.org>,
	Networking <netdev@vger.kernel.org>,
	Linux Memory Management List <linux-mm@kvack.org>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	Kernel Team <Kernel-team@fb.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	"rick.p.edgecombe@intel.com" <rick.p.edgecombe@intel.com>,
	"imbrenda@linux.ibm.com" <imbrenda@linux.ibm.com>
Subject: Re: [PATCH bpf 1/2] vmalloc: replace VM_NO_HUGE_VMAP with VM_ALLOW_HUGE_VMAP
Date: Sun, 10 Apr 2022 01:25:40 +0000	[thread overview]
Message-ID: <4D0216A9-E667-4936-8FF7-A1B94E973720@fb.com> (raw)
In-Reply-To: <YlEZahPCTI/qh/6u@infradead.org>



> On Apr 8, 2022, at 10:28 PM, Christoph Hellwig <hch@infradead.org> wrote:
> 
> On Fri, Apr 08, 2022 at 03:34:42PM -0700, Song Liu wrote:
>> Huge page backed vmalloc memory could benefit performance in many cases.
>> Since some users of vmalloc may not be ready to handle huge pages,
>> VM_NO_HUGE_VMAP was introduced to allow vmalloc users to opt-out huge
>> pages. However, it is not easy to add VM_NO_HUGE_VMAP to all the users
>> that may try to allocate >= PMD_SIZE pages, but are not ready to handle
>> huge pages properly.
>> 
>> Replace VM_NO_HUGE_VMAP with an opt-in flag, VM_ALLOW_HUGE_VMAP, so that
>> users that benefit from huge pages could ask specificially.
> 
> Given that the huge page backing was added explicitly for some big boot
> time allocated hashed,those should probably have the VM_ALLOW_HUGE_VMAP
> added from the start (maybe not in this patch, but certainly in this
> series).  We'll probably also need a vmalloc_huge interface for those.

Will add it in v2. 

Thanks,
Song


  reply	other threads:[~2022-04-10  1:26 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-08 22:34 [PATCH bpf 0/2] vmalloc: bpf: introduce VM_ALLOW_HUGE_VMAP Song Liu
2022-04-08 22:34 ` [PATCH bpf 1/2] vmalloc: replace VM_NO_HUGE_VMAP with VM_ALLOW_HUGE_VMAP Song Liu
2022-04-09  5:28   ` Christoph Hellwig
2022-04-10  1:25     ` Song Liu [this message]
2022-04-08 22:34 ` [PATCH bpf 2/2] bpf: use vmalloc with VM_ALLOW_HUGE_VMAP for bpf_prog_pack Song Liu
2022-04-09  5:29   ` Christoph Hellwig
2022-04-10  1:34     ` Song Liu
2022-04-11  6:56       ` Christoph Hellwig
2022-04-11 22:18         ` Song Liu
2022-04-09 11:43 ` [PATCH bpf 0/2] vmalloc: bpf: introduce VM_ALLOW_HUGE_VMAP Thorsten Leemhuis
2022-04-10  1:36   ` Song Liu

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