From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5C1DFC624C6 for ; Tue, 1 Sep 2026 07:59:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=iJv/WiakOodAqFIubQ5HTmHL0TDtf9MpNqrzEXUw2fg=; b=x3Ipl+PRbYJREBceVIruNQviRJ v0dM0KS6KoKRQ2A2SJe7ugLIyNKdtEUJfKycwopnBSIZqbG3X+3ijkFgET84SRPDm1dDkIJHwART3 Fnd8qLA9UoEYo6LGB45SM3jEJQApXPVKyEbeIJVFHVrhgHp4/8wr2bIEw2IVXv5bLSjqEO9JC+OEN MfqR3dPuMA4ozL90ukfej5QBSzNaMz5JfYiina1P9DmaSiH5fE6HjHwYk1Zhm+Q5pVmfybypX6HDk YF3Q3x9L8ugazIOtKFXwayJ/Ok7/k8ZOP3QFN5rmw9XBEky101mHH8qU2bDs+RYZsxtpAcUtJWPoK p0YcUWeQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x1JOw-0000000BBjx-1FFS; Tue, 01 Sep 2026 07:59:26 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1x1JOv-0000000BBjq-1gCz for linux-arm-kernel@lists.infradead.org; Tue, 01 Sep 2026 07:59:25 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id A0667601DB; Tue, 1 Sep 2026 07:59:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 201A81F000E9; Tue, 1 Sep 2026 07:59:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788249564; bh=iJv/WiakOodAqFIubQ5HTmHL0TDtf9MpNqrzEXUw2fg=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=P7SEFFP8puwZXZp/YRq5bm12kLhga+lgh99B8rQeYLWPKvjGgDXAgg7amgbvop6gs KnFbcm9PWiLs6fpRX3X9ZFziRD/tbsK3eH/C4U9q+apMvreDXnEx9yuMWrWXaAlfn9 RfE+EypR5zdZI4scQXJRBlRBhEahbdQVPKXgYGzRzl4sArWd1u++y7ARbEBAYmsoti qa/YYnJeh63FtQSZKwP6986LY6PCjMAcEQlpM6IXvbI4ROaA1SfUtvjcxi9CnB5UZH Nk9IDitG/j2LUr0suo0oUruy11Tq+byoKby/mpiq0sCo0dpWi4sYmz38BnnJLGVmE9 9mRRThkgaqcJA== Date: Tue, 1 Sep 2026 10:59:16 +0300 From: Mike Rapoport To: David Laight Cc: Eli Billauer , Arnd Bergmann , Brad Warrum , Greg Kroah-Hartman , Michal Simek , Ritu Agarwal , Andrew Morton , David Hildenbrand , Matthew Wilcox , Vlastimil Babka , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH 2/4] char: xillybus: replace __get_free_pages() with kmalloc() Message-ID: References: <20260830-char-misc-v1-0-05e2ce44f291@kernel.org> <20260830-char-misc-v1-2-05e2ce44f291@kernel.org> <20260831123937.32255a49@pumpkin> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260831123937.32255a49@pumpkin> X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Aug 31, 2026 at 12:39:37PM +0100, David Laight wrote: > On Mon, 31 Aug 2026 12:13:08 +0200 > Eli Billauer wrote: > > > On 30/08/2026 9:47, Mike Rapoport (Microsoft) wrote: > > > fifo_init() allocates the buffers backing the software FIFO and > > > endpoint_alloc() allocates the transfer buffers of a USB endpoint. > > > > > > These buffers can be allocated with kmalloc() as there's nothing special > > > about them to go directly to the page allocator. > > > > Except that they are a bit large. > > > > fifo_init() may be requested to allocate up to 256 MB of buffer memory. > > This memory resource is split into an array of buffers (fifo->mem[i]), > > each 64 kiB (or less, if there's trouble obtaining segments of this size). > > Would it really make sense to allocate the four buffers separately? > And/or use vmalloc(). My understanding is that the buffers don't need to be physically contiguous and vmalloc()ing the entire fifo->mem in one go should work. Eli, what do you think? > David -- Sincerely yours, Mike.