From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailout2.w1.samsung.com (mailout2.w1.samsung.com [210.118.77.12]) (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 7A77F3F7A9A for ; Fri, 27 Mar 2026 14:42:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=210.118.77.12 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774622532; cv=none; b=nRt4CIyS2D9iew8TTasHGonVrVnf2Iq34Y6tGzaZDbsNc3Xe7wExuPj5y61C+nK7zqwm0ykNqozR1iA9eATvCqzJ+oDhZJ2HRZeCCysHegOYvMlc3/Zfj5ZNG1xXxT2Og+tWAimgFuNxVsmOhcqiBpgM5MhiWnkfg7smxgsGDjs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774622532; c=relaxed/simple; bh=ylA7ih9c3zmN2K3V4NZ6Ra1Y0GHKDBSmQnTMK3iaQ9U=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:From:In-Reply-To: Content-Type:References; b=hVb0eB3nZbLcYf7g13w1yToX+RGCOsUDZi4FpXEMjbH7SQSXF6IdxYkKJ37e0SDsF/WTt4ntxNksvfAzYKC0x+E4sLxFbdle7CHPhtsknzUrp+t/w6sNH/zyaxJxTB9KymVEk9OrLsdELgvbTVxy/JPhnUUNFSRl7c29CHf/BjY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=samsung.com; spf=pass smtp.mailfrom=samsung.com; dkim=pass (1024-bit key) header.d=samsung.com header.i=@samsung.com header.b=f9GADw8e; arc=none smtp.client-ip=210.118.77.12 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=samsung.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=samsung.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=samsung.com header.i=@samsung.com header.b="f9GADw8e" Received: from eucas1p2.samsung.com (unknown [182.198.249.207]) by mailout2.w1.samsung.com (KnoxPortal) with ESMTP id 20260327144202euoutp02d190d18b4d65e071827245c353237c50~gucggT3uK3049430494euoutp02_ for ; Fri, 27 Mar 2026 14:42:02 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 mailout2.w1.samsung.com 20260327144202euoutp02d190d18b4d65e071827245c353237c50~gucggT3uK3049430494euoutp02_ DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsung.com; s=mail20170921; t=1774622522; bh=7bk0dNR0zbUSNuzz8HU1AITn/eIsQuxRxjKTkb9qTHA=; h=Date:Subject:To:Cc:From:In-Reply-To:References:From; b=f9GADw8exPA2pVqpc0qboQT+Sy/jnB8ErnC5Qxv0djC6GCim3q4etY2PpzH24UY8O 7Qep4pkrHEwLMs1ACeuzsMQ+fh0iZ+IbqDSH3iKHqqqJLg/2MCUB/uj6DQCJzOZpm3 rD07b3C5yrAHKWmF8/mfyXaa3FgFSCYIyPSQnJ8E= Received: from eusmtip2.samsung.com (unknown [203.254.199.222]) by eucas1p2.samsung.com (KnoxPortal) with ESMTPA id 20260327144201eucas1p2fba2f0b4d62780ba545ca81d1e42397f~gucgC2W412070520705eucas1p2u; Fri, 27 Mar 2026 14:42:01 +0000 (GMT) Received: from [106.210.134.192] (unknown [106.210.134.192]) by eusmtip2.samsung.com (KnoxPortal) with ESMTPA id 20260327144159eusmtip22ec2e6c7eb865005539396807c731900~guceHbtB72669926699eusmtip2n; Fri, 27 Mar 2026 14:41:59 +0000 (GMT) Message-ID: <455f1419-77ed-419d-b53e-e787dbd638a8@samsung.com> Date: Fri, 27 Mar 2026 15:41:59 +0100 Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Betterbird (Windows) Subject: Re: [PATCH] mm/slab: align kmalloc to cacheline when DMA API debugging is active To: Mikhail Gavrilov , "Vlastimil Babka (SUSE)" Cc: Catalin Marinas , harry.yoo@oracle.com, akpm@linux-foundation.org, hao.li@linux.dev, cl@gentwo.org, rientjes@google.com, roman.gushchin@linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, stern@rowland.harvard.edu, linux@roeck-us.net, andy.shevchenko@gmail.com, hch@lst.de, Jeff.kirsher@gmail.com, Robin Murphy Content-Language: en-US From: Marek Szyprowski In-Reply-To: Content-Transfer-Encoding: 8bit X-CMS-MailID: 20260327144201eucas1p2fba2f0b4d62780ba545ca81d1e42397f X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-RootMTR: 20260327122625eucas1p10eabcb31aada4e11b5c2ebcff4cb3c39 X-EPHeader: CA X-CMS-RootMailID: 20260327122625eucas1p10eabcb31aada4e11b5c2ebcff4cb3c39 References: <20260327055846.248829-1-mikhail.v.gavrilov@gmail.com> On 27.03.2026 15:37, Mikhail Gavrilov wrote: > On Fri, Mar 27, 2026 at 7:30 PM Vlastimil Babka (SUSE) > wrote: >> So what about Harry's proposal [1]? Mikhail seems to be on board? [2] >> >> It seems it would achieve the goal that enabling DMA_API_DEBUG doesn't >> change the kernel behavior? But I don't know this area too well so >> maybe there's a catch. >> >> [1] https://lore.kernel.org/all/acYlxRBhSMcwBnja@hyeyoo/ >> [2] https://lore.kernel.org/all/CABXGCsO_C8%2B%2B4%2BoPfZ%2BbQyrBnEGy5JFpXHkGNpfy%2B8%3D5BvVNfg@mail.gmail.com/ > Hi Vlastimil, > > Yes, I've already sent v2 based on Harry's suggestion: > https://lore.kernel.org/all/20260327124156.24820-1-mikhail.v.gavrilov@gmail.com/ > > It adds a dma_get_cache_alignment() >= L1_CACHE_BYTES check in > add_dma_entry() instead of changing ARCH_KMALLOC_MINALIGN, so > enabling DMA_API_DEBUG no longer affects allocator behavior. This looks like a good fix, but let me think a bit more about all possible cases. Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland