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 E06D5C00140 for ; Wed, 10 Aug 2022 23:40:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233740AbiHJXko (ORCPT ); Wed, 10 Aug 2022 19:40:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36724 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233589AbiHJXkk (ORCPT ); Wed, 10 Aug 2022 19:40:40 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C1E45BA0 for ; Wed, 10 Aug 2022 16:40:38 -0700 (PDT) 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 ams.source.kernel.org (Postfix) with ESMTPS id 7D8BCB81DDF for ; Wed, 10 Aug 2022 23:40:37 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 15AEDC433C1; Wed, 10 Aug 2022 23:40:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1660174836; bh=kmbKpooLMJ+8p+e4UOjJI3V6WgOxHFFhgtpmcUnw97w=; h=Date:To:From:Subject:From; b=TodCt9GT6pzfGXGQQ/YOn1S8TfpGLbMDA+z2J13rvrPIIH6kqCrvh+ilaV6vAm2Zr +EdxA05Ph7DjrCcz706AvBnl6lAuC5mqDABAxSiFsdrEQ5fb2p/SVOwyAJoNvHYOv2 wgH8cBzigsBurhI1j8oaxWSjG+ycSs47+L5n4SlU= Date: Wed, 10 Aug 2022 16:40:35 -0700 To: mm-commits@vger.kernel.org, willy@infradead.org, songmuchun@bytedance.com, slava@dubeyko.com, keescook@chromium.org, ira.weiny@intel.com, bvanassche@acm.org, axboe@kernel.dk, fmdefrancesco@gmail.com, akpm@linux-foundation.org From: Andrew Morton Subject: + hfsplus-convert-kmap-to-kmap_local_page-in-btreec.patch added to mm-nonmm-unstable branch Message-Id: <20220810234036.15AEDC433C1@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: hfsplus: convert kmap() to kmap_local_page() in btree.c has been added to the -mm mm-nonmm-unstable branch. Its filename is hfsplus-convert-kmap-to-kmap_local_page-in-btreec.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/hfsplus-convert-kmap-to-kmap_local_page-in-btreec.patch This patch will later appear in the mm-nonmm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: "Fabio M. De Francesco" Subject: hfsplus: convert kmap() to kmap_local_page() in btree.c Date: Tue, 9 Aug 2022 22:31:05 +0200 kmap() is being deprecated in favor of kmap_local_page(). There are two main problems with kmap(): (1) It comes with an overhead as mapping space is restricted and protected by a global lock for synchronization and (2) it also requires global TLB invalidation when the kmap's pool wraps and it might block when the mapping space is fully utilized until a slot becomes available. With kmap_local_page() the mappings are per thread, CPU local, can take page faults, and can be called from any context (including interrupts). It is faster than kmap() in kernels with HIGHMEM enabled. Furthermore, the tasks can be preempted and, when they are scheduled to run again, the kernel virtual addresses are restored and are still valid. Since its use in btree.c is safe everywhere, it should be preferred. Therefore, replace kmap() with kmap_local_page() in btree.c. Tested in a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel with HIGHMEM64GB enabled. Link: https://lkml.kernel.org/r/20220809203105.26183-5-fmdefrancesco@gmail.com Signed-off-by: Fabio M. De Francesco Suggested-by: Ira Weiny Reviewed-by: Ira Weiny Reviewed-by: Viacheslav Dubeyko Cc: Bart Van Assche Cc: Jens Axboe Cc: Kees Cook Cc: Matthew Wilcox Cc: Muchun Song Signed-off-by: Andrew Morton --- fs/hfsplus/btree.c | 28 ++++++++++++++-------------- 1 file changed, 14 insertions(+), 14 deletions(-) --- a/fs/hfsplus/btree.c~hfsplus-convert-kmap-to-kmap_local_page-in-btreec +++ a/fs/hfsplus/btree.c @@ -163,7 +163,7 @@ struct hfs_btree *hfs_btree_open(struct goto free_inode; /* Load the header */ - head = (struct hfs_btree_header_rec *)(kmap(page) + + head = (struct hfs_btree_header_rec *)(kmap_local_page(page) + sizeof(struct hfs_bnode_desc)); tree->root = be32_to_cpu(head->root); tree->leaf_count = be32_to_cpu(head->leaf_count); @@ -240,12 +240,12 @@ struct hfs_btree *hfs_btree_open(struct (tree->node_size + PAGE_SIZE - 1) >> PAGE_SHIFT; - kunmap(page); + kunmap_local(head); put_page(page); return tree; fail_page: - kunmap(page); + kunmap_local(head); put_page(page); free_inode: tree->inode->i_mapping->a_ops = &hfsplus_aops; @@ -292,7 +292,7 @@ int hfs_btree_write(struct hfs_btree *tr return -EIO; /* Load the header */ page = node->page[0]; - head = (struct hfs_btree_header_rec *)(kmap(page) + + head = (struct hfs_btree_header_rec *)(kmap_local_page(page) + sizeof(struct hfs_bnode_desc)); head->root = cpu_to_be32(tree->root); @@ -304,7 +304,7 @@ int hfs_btree_write(struct hfs_btree *tr head->attributes = cpu_to_be32(tree->attributes); head->depth = cpu_to_be16(tree->depth); - kunmap(page); + kunmap_local(head); set_page_dirty(page); hfs_bnode_put(node); return 0; @@ -395,7 +395,7 @@ struct hfs_bnode *hfs_bmap_alloc(struct off += node->page_offset; pagep = node->page + (off >> PAGE_SHIFT); - data = kmap(*pagep); + data = kmap_local_page(*pagep); off &= ~PAGE_MASK; idx = 0; @@ -408,7 +408,7 @@ struct hfs_bnode *hfs_bmap_alloc(struct idx += i; data[off] |= m; set_page_dirty(*pagep); - kunmap(*pagep); + kunmap_local(data); tree->free_nodes--; mark_inode_dirty(tree->inode); hfs_bnode_put(node); @@ -418,14 +418,14 @@ struct hfs_bnode *hfs_bmap_alloc(struct } } if (++off >= PAGE_SIZE) { - kunmap(*pagep); - data = kmap(*++pagep); + kunmap_local(data); + data = kmap_local_page(*++pagep); off = 0; } idx += 8; len--; } - kunmap(*pagep); + kunmap_local(data); nidx = node->next; if (!nidx) { hfs_dbg(BNODE_MOD, "create new bmap node\n"); @@ -441,7 +441,7 @@ struct hfs_bnode *hfs_bmap_alloc(struct off = off16; off += node->page_offset; pagep = node->page + (off >> PAGE_SHIFT); - data = kmap(*pagep); + data = kmap_local_page(*pagep); off &= ~PAGE_MASK; } } @@ -491,7 +491,7 @@ void hfs_bmap_free(struct hfs_bnode *nod } off += node->page_offset + nidx / 8; page = node->page[off >> PAGE_SHIFT]; - data = kmap(page); + data = kmap_local_page(page); off &= ~PAGE_MASK; m = 1 << (~nidx & 7); byte = data[off]; @@ -499,13 +499,13 @@ void hfs_bmap_free(struct hfs_bnode *nod pr_crit("trying to free free bnode " "%u(%d)\n", node->this, node->type); - kunmap(page); + kunmap_local(data); hfs_bnode_put(node); return; } data[off] = byte & ~m; set_page_dirty(page); - kunmap(page); + kunmap_local(data); hfs_bnode_put(node); tree->free_nodes++; mark_inode_dirty(tree->inode); _ Patches currently in -mm which might be from fmdefrancesco@gmail.com are hfsplus-unmap-the-page-in-the-fail_page-label.patch hfsplus-convert-kmap-to-kmap_local_page-in-bnodec.patch hfsplus-convert-kmap-to-kmap_local_page-in-bitmapc.patch hfsplus-convert-kmap-to-kmap_local_page-in-btreec.patch