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Tue, 30 Jul 2024 00:30:05 -0400 X-MC-Unique: Uh0Lk31INByO6bzV24RUDw-1 Received: from mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.15]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 6341A1955D55; Tue, 30 Jul 2024 04:30:03 +0000 (UTC) Received: from localhost (unknown [10.72.112.91]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 9543E1955D42; Tue, 30 Jul 2024 04:30:01 +0000 (UTC) Date: Tue, 30 Jul 2024 12:29:57 +0800 From: Baoquan He To: Hailong Liu Cc: Barry Song <21cnbao@gmail.com>, Andrew Morton , Uladzislau Rezki , Christoph Hellwig , Lorenzo Stoakes , Vlastimil Babka , Michal Hocko , Matthew Wilcox , Tangquan Zheng , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH v2] mm/vmalloc: fix incorrect __vmap_pages_range_noflush() if vm_area_alloc_pages() from high order fallback to order0 Message-ID: References: <20240725035318.471-1-hailong.liu@oppo.com> <20240725164003.ft6huabwa5dqoy2g@oppo.com> <20240730032447.avaoa5uhcxdkcjzs@oppo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240730032447.avaoa5uhcxdkcjzs@oppo.com> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 0C54720029 X-Stat-Signature: zobygst1re1hjz3h8ueswsy1fo334rqx X-HE-Tag: 1722313812-321551 X-HE-Meta: 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 KrwEDSw8 PcCLfC6ilbwezYfqxL4jYvfR3/XB1xp0rg5+wMtLjYteYLb3A4UxUpeEzpFliQGlzdVN1CefRQEngyZxxaEiqgNUlImk9bMNN76nTYdzUEcnzWkwt+hU0IEezLQ4o2NAkw7gesV5FiGSJUSvcNckv75c6BxLlWyKJtElklcghKcbQgPtmH/WqpaMfxZwkWJLoj6yf0mA5uoTvudr96lE+uFeJKFOzaWXqCrTReaOUBd2PHYTsxi/JFpHxCrnA2I2xfo31z0P9izb8aDHlsQxaimiHasr60IFDeD1eUBTCnYJowlgxhY0sR6VMoA8W86P+d7vF662NAZN324n2HqLCYwV938zCwrBv3sgXDOYZU1VPOxrGHlRw8VSXsA== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 07/30/24 at 11:24am, Hailong Liu wrote: > On Mon, 29. Jul 09:48, Baoquan He wrote: > [...] > > Hi Hailong, > > > > Please feel free to collect them to post formal patch, maybe two > > patches, one is to allow non-nofail to fallback to order-0 in > > vm_area_alloc_pages(), the other is passing out the fallbacked > > page_order to vmap_pages_range() if it's OK. > Sorry for late response. I personally prefer to revert part of > the problematic patch. There are several reasons: > - Save memory usage if high order allocation failed. > - If nofail and fallback to order0 in vmalloc huge allocation, > actually the allocation is alighed with PMD_SIZE or not PAGE_SHIFT. It's OK, maybe you can post patch to show what it looks like, we can review and discuss there. > > You might be concerned about performance issues. But IMO, > - If we fallback to order0, we can make use of bulk allocator. > - Maybe we can remove VM_ALLOW_HUGE_VMAP in kvmalloc. > > I am not sure if I have misunderstood anything. If I have, please > let me know. > > > > Thanks > > Baoquan > > > > > > -- > help you, help me, > Hailong. >