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[2607:7c80:54:e::133]) by mx.google.com with ESMTPS id z11si7770752pgv.333.2019.05.10.10.11.12 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 10 May 2019 10:11:12 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of batv+4a48006d3eb72708861b+5738+infradead.org+hch@bombadil.srs.infradead.org designates 2607:7c80:54:e::133 as permitted sender) client-ip=2607:7c80:54:e::133; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20170209 header.b=e6wUwdxW; spf=pass (google.com: best guess record for domain of batv+4a48006d3eb72708861b+5738+infradead.org+hch@bombadil.srs.infradead.org designates 2607:7c80:54:e::133 as permitted sender) smtp.mailfrom=BATV+4a48006d3eb72708861b+5738+infradead.org+hch@bombadil.srs.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=RN9MRAYL04J62QQlXQPaUff9V9wYHA8yoc3KdaVugcA=; b=e6wUwdxWd9wR3TUAIHqoYksa8 w5RgqCu64V287AQTt+74ZJrMoOl3W7+WQSRzar+7PaFRuOH3yfmUwy9ctvV5PgoHi6ZKikdg5+teE XQ+UIA77q14N2k0AT5C1MufgBRXlFOnKGROzxrDHQAeAThM/uYPGO6Fs8EoVwnuXMNgBYBeDic3kN zHhEIa3n7nVSnFcGy8OMJNQySOMVMV215h4+BsbhTWUYIN91De7jQOGmeAMjz+ZrLAHzuGv2eJ0k6 P+UYM+mHVELGhVyfx9eTi7a/AgKhkJQ07/2bOMQx9B7soP8XUY4VQnzoEijWaFnO13E0+uASEW5wt XtvkFZUuw==; Received: from hch by bombadil.infradead.org with local (Exim 4.90_1 #2 (Red Hat Linux)) id 1hP939-0001ng-08; Fri, 10 May 2019 17:11:11 +0000 Date: Fri, 10 May 2019 10:11:10 -0700 From: Christoph Hellwig To: Matthew Wilcox Cc: David Howells , Jesper Dangaard Brouer , Christoph Lameter , Andrew Morton , linux-mm Subject: Re: Bulk kmalloc Message-ID: <20190510171110.GA3449@infradead.org> References: <20190510135031.1e8908fd@carbon> <14647.1557415738@warthog.procyon.org.uk> <3261.1557505403@warthog.procyon.org.uk> <20190510165001.GA3162@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190510165001.GA3162@bombadil.infradead.org> User-Agent: Mutt/1.9.2 (2017-12-15) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html 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: On Fri, May 10, 2019 at 09:50:01AM -0700, Matthew Wilcox wrote: > kvmalloc() is the normal solution here. Usual reasons for not being > able to do that would be that you do DMA to the memory or that you need > to be able to free each of these objects individually. Note that you absolutely can do DMA to vmalloced buffers. It just is very painful due to the manual coherency management..