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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 465A2C61DA3 for ; Fri, 3 Mar 2023 22:26:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233675AbjCCW0H (ORCPT ); Fri, 3 Mar 2023 17:26:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57462 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232601AbjCCWZo (ORCPT ); Fri, 3 Mar 2023 17:25:44 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9144164226; Fri, 3 Mar 2023 14:18:37 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 7B7DC6185C; Fri, 3 Mar 2023 22:07:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 282F7C433EF; Fri, 3 Mar 2023 22:07:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1677881278; bh=TUin5dJ6wozQ4pS9/Xwfz0PAwCO0bOaleI5RUw7nM5Y=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=n4u6Y1cfyedCPK4JiZI9UhSiCl8Ya3YDVva5Mdk8nPYGkTjd/qEEYWZwLKfy73CfX b4sRiBbcd0Rj6bVbwIV4sdnA9ZS6++xyMUo/DHlSVVuLB/qS9LKFd1rggM5ZsbXIOX t3s7yJqFrWhY5FMarh/PX0BSm7LgOGDL8c3Q+B9ZvrMLWVzMJaCQpwGD/w1ri/TbWZ iMpYkP0+dyWQVqgPjlZTMqEhJaibj8tAlU8lNqhphNXefk9X9/twyte4IH5HSU9z5V RcpI8GicZ4BVzdFIn/lglbpzOGieosRurelA8gisT8HKtu2zPdqE9qXGf9TILtHIY1 JGJmES8sjqeFA== Date: Fri, 3 Mar 2023 15:07:55 -0700 From: Keith Busch To: Luis Chamberlain Cc: Matthew Wilcox , Theodore Ts'o , Pankaj Raghav , Daniel Gomez , Javier =?iso-8859-1?Q?Gonz=E1lez?= , lsf-pc@lists.linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-block@vger.kernel.org Subject: Re: [LSF/MM/BPF TOPIC] Cloud storage optimizations Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Fri, Mar 03, 2023 at 01:45:48PM -0800, Luis Chamberlain wrote: > > You'd hope most of it is left to FS + MM, but I'm not yet sure that's > quite it yet. Initial experimentation shows just enabling > PAGE_SIZE > physical & logical block NVMe devices gets brought down to 512 bytes. > That seems odd to say the least. Would changing this be an issue now? I think you're talking about removing this part: --- diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index c2730b116dc68..2c528f56c2973 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -1828,17 +1828,7 @@ static void nvme_update_disk_info(struct gendisk *disk, unsigned short bs = 1 << ns->lba_shift; u32 atomic_bs, phys_bs, io_opt = 0; - /* - * The block layer can't support LBA sizes larger than the page size - * yet, so catch this early and don't allow block I/O. - */ - if (ns->lba_shift > PAGE_SHIFT) { - capacity = 0; - bs = (1 << 9); - } - blk_integrity_unregister(disk); - atomic_bs = phys_bs = bs; if (id->nabo == 0) { /* -- This is what happens today if the driver were to let the disk create with its actual size (testing 8k LBA size on x86): BUG: kernel NULL pointer dereference, address: 0000000000000008 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] SMP CPU: 10 PID: 115 Comm: kworker/u32:2 Not tainted 6.2.0-00032-gdb7183e3c314-dirty #105 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 Workqueue: nvme-wq nvme_scan_work RIP: 0010:create_empty_buffers+0x24/0x240 Code: 66 0f 1f 44 00 00 0f 1f 44 00 00 41 54 49 89 d4 ba 01 00 00 00 55 53 48 89 fb e8 17 f5 ff ff 48 89 c5 48 89 c2 eb 03 48 89 ca <48> 8b 4a 08 4c 09 22 48 85 c9 75 f1 48 89 6a 08 48 8b 43 18 48 8d RSP: 0000:ffffc900004578f0 EFLAGS: 00010286 RAX: 0000000000000000 RBX: ffffea0000152580 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffea0000152580 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000013 R10: ffff88803ecb6c18 R11: 0000000000000000 R12: 0000000000000000 R13: ffffea0000152580 R14: 0000000000100cc0 R15: ffff888017030288 FS: 0000000000000000(0000) GS:ffff88803ec80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000008 CR3: 0000000002c2a001 CR4: 0000000000770ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: ? blkdev_readahead+0x20/0x20 create_page_buffers+0x79/0x90 block_read_full_folio+0x58/0x410 ? blkdev_write_begin+0x20/0x20 ? xas_store+0x56/0x5b0 ? xas_load+0x8/0x40 ? xa_get_order+0x51/0xe0 ? __mod_memcg_lruvec_state+0x41/0x90 ? blkdev_readahead+0x20/0x20 ? blkdev_readahead+0x20/0x20 filemap_read_folio+0x41/0x2a0 ? scan_shadow_nodes+0x30/0x30 ? blkdev_readahead+0x20/0x20 ? folio_add_lru+0x2d/0x40 ? blkdev_readahead+0x20/0x20 do_read_cache_folio+0x103/0x420 ? __switch_to_asm+0x3a/0x60 ? __switch_to_asm+0x34/0x60 ? get_page_from_freelist+0x735/0x1070 read_part_sector+0x2f/0xa0 read_lba+0xa2/0x150 efi_partition+0xdb/0x760 ? snprintf+0x49/0x60 ? is_gpt_valid.part.5+0x3f0/0x3f0 bdev_disk_changed+0x1ce/0x560 blkdev_get_whole+0x73/0x80 blkdev_get_by_dev+0x199/0x2e0 disk_scan_partitions+0x63/0xd0 device_add_disk+0x3c0/0x3d0 nvme_scan_ns+0x574/0xcc0 ? nvme_scan_work+0x23a/0x3f0 nvme_scan_work+0x23a/0x3f0 process_one_work+0x1da/0x3a0 worker_thread+0x205/0x3a0 ? process_one_work+0x3a0/0x3a0 kthread+0xc0/0xe0 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork+0x1f/0x30