From mboxrd@z Thu Jan 1 00:00:00 1970 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.subspace.kernel.org (Postfix) with ESMTPS id B93621411DE for ; Mon, 12 May 2025 04:24:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747023886; cv=none; b=TBfrFzx3FqrOdVkru3B7mA2xiyB8mLcgK5WuRU+FNUKJ0hhOt8eUpPeFrvIFKiwrstVGtm4GKQFIT0e2DcGzkjiJBu/UmGCk7vR9YdA+ckGSIz5tYbce8qutPlVpe4bFFDRnkQMgJ5kUJS3p27ETCmjVbGsVjglUOEvdkeOvOok= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747023886; c=relaxed/simple; bh=PJavjRWOpdACPSdJOLRdx5a3PHn5fJQp3edx2xrkSbU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=sWY0jXx0gL6IgicoM5IL4Kx0NmApRBLSddts7rv1wNt+zLmqkXJH7cYyNuqPfoFejpLBld6hdte8lfhqWA+EWH48HXqHbZIYljKNIEe9C/W6yvklxlSgSrjDnBRwXgDrSYtRPKaakFUct5N4N94RMC6CFrbk+Se/SZzBBcGMhDw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=IknVuQA3; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="IknVuQA3" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; 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; bh=qC9e38yOBZPe5pOACVwKPnNvAHgjR/ZBlShq6j7WTag=; b=IknVuQA3bofq78chLGBVguILEK Eq5WZPcPxZFj51BBLYvMwVTJuPcVNFbc5UQkpWk2i0uGsvUomKIrMc4p4wKne3m+pOlqyBYa3TQg9 q+9sbdyNCBtaogyVvdEEHWJM0EDGfMejH5hGwnDu6Rp6nMy94RBFadLaxMEmQVkZL38hOwPU35o/c seg+t3BoVLVbRZuqbT7O2qbndbzhuPq66Xms2tW2i8LpqfWvvGfzZA/EXArTvBOeVSbPyzNbt1bjf e1/2QvbpE9TbBhvSBKjsm97XFAM+tNy4vL/3qyO2G5ssQ45pFm5QC5UafPpcACyzXnYofcKheUowR W2ZnPcvQ==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1uEKiU-00000008Kks-3XKM; Mon, 12 May 2025 04:24:38 +0000 Date: Sun, 11 May 2025 21:24:38 -0700 From: Christoph Hellwig To: Andrew Lunn Cc: Ilias Apalodimas , Jakub Kicinski , Byungchul Park , willy@infradead.org, almasrymina@google.com, kernel_team@skhynix.com, 42.hyeyoo@gmail.com, linux-mm@kvack.org, hawk@kernel.org, netdev@vger.kernel.org Subject: Re: [RFC] shrinking struct page (part of page pool) Message-ID: References: <20250414013627.GA9161@system.software.com> <20250414015207.GA50437@system.software.com> <20250414163002.166d1a36@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Sat, May 10, 2025 at 03:53:47PM +0200, Andrew Lunn wrote: > > Random thoughts here until I look at the patches. > > The concept of devices doing DMA + recycling the used buffer > > transcends networking. > > Do you know of any other subsystem which takes a page, splits it into > two, and then uses each half independently for DMA and recycling. A > typical packet is 1514 octets, so you can get two in a page. The mm/dmapool.c code is all about this.