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 25544C4167B for ; Mon, 27 Nov 2023 17:22:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229541AbjK0RWk (ORCPT ); Mon, 27 Nov 2023 12:22:40 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58798 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343545AbjK0RFw (ORCPT ); Mon, 27 Nov 2023 12:05:52 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D980C327B for ; Mon, 27 Nov 2023 09:00:51 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4AF7FC433C7; Mon, 27 Nov 2023 17:00:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1701104451; bh=Whft52qpN+Yr+ZAOtkw2jaYPkVuPnxO4xB1eDJAkmRc=; h=Date:To:From:Subject:From; b=1xBCJpiYqWhAF0gHkdTgpYRnQBGJa/VWcYAQ4cx1DwvePHXaTL4uVCgph3Bv/+HdF XUXBVIuRyzd8iPvd2CmRK52HqINc3kIk5dcOPh/fROaxTptm7dTkh75AKXP8YXUvrL /ytzpZRkKn/GKNCIVB6X7iNmzS3z2SNgTp6ssBGs= Date: Mon, 27 Nov 2023 09:00:50 -0800 To: mm-commits@vger.kernel.org, sjenning@redhat.com, ira.weiny@intel.com, ddstreet@ieee.org, fabio.maria.de.francesco@linux.intel.com, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-zswap-replace-kmap_atomic-with-kmap_local_page.patch added to mm-unstable branch Message-Id: <20231127170051.4AF7FC433C7@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: mm/zswap: replace kmap_atomic() with kmap_local_page() has been added to the -mm mm-unstable branch. Its filename is mm-zswap-replace-kmap_atomic-with-kmap_local_page.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-zswap-replace-kmap_atomic-with-kmap_local_page.patch This patch will later appear in the mm-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: mm/zswap: replace kmap_atomic() with kmap_local_page() Date: Mon, 27 Nov 2023 16:55:21 +0100 kmap_atomic() has been deprecated in favor of kmap_local_page(). Therefore, replace kmap_atomic() with kmap_local_page() in zswap.c. kmap_atomic() is implemented like a kmap_local_page() which also disables page-faults and preemption (the latter only in !PREEMPT_RT kernels). The kernel virtual addresses returned by these two API are only valid in the context of the callers (i.e., they cannot be handed to other threads). With kmap_local_page() the mappings are per thread and CPU local like in kmap_atomic(); however, they can handle page-faults and can be called from any context (including interrupts). The tasks that call kmap_local_page() can be preempted and, when they are scheduled to run again, the kernel virtual addresses are restored and are still valid. In mm/zswap.c, the blocks of code between the mappings and un-mappings do not depend on the above-mentioned side effects of kmap_atomic(), so that the mere replacements of the old API with the new one is all that is required (i.e., there is no need to explicitly call pagefault_disable() and/or preempt_disable()). Link: https://lkml.kernel.org/r/20231127160058.586446-1-fabio.maria.de.francesco@linux.intel.com Signed-off-by: Fabio M. De Francesco Cc: Ira Weiny Cc: Seth Jennings Cc: Dan Streetman Signed-off-by: Andrew Morton --- mm/zswap.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) --- a/mm/zswap.c~mm-zswap-replace-kmap_atomic-with-kmap_local_page +++ a/mm/zswap.c @@ -1267,16 +1267,16 @@ bool zswap_store(struct folio *folio) } if (zswap_same_filled_pages_enabled) { - src = kmap_atomic(page); + src = kmap_local_page(page); if (zswap_is_page_same_filled(src, &value)) { - kunmap_atomic(src); + kunmap_local(src); entry->swpentry = swp_entry(type, offset); entry->length = 0; entry->value = value; atomic_inc(&zswap_same_filled_pages); goto insert_entry; } - kunmap_atomic(src); + kunmap_local(src); } if (!zswap_non_same_filled_pages_enabled) @@ -1422,9 +1422,9 @@ bool zswap_load(struct folio *folio) spin_unlock(&tree->lock); if (!entry->length) { - dst = kmap_atomic(page); + dst = kmap_local_page(page); zswap_fill_page(dst, entry->value); - kunmap_atomic(dst); + kunmap_local(dst); ret = true; goto stats; } _ Patches currently in -mm which might be from fabio.maria.de.francesco@linux.intel.com are mm-util-use-kmap_local_page-in-memcmp_pages.patch mm-memory-use-kmap_local_page-in-__wp_page_copy_user.patch mm-mempool-replace-kmap_atomic-with-kmap_local_page.patch mm-page_poison-replace-kmap_atomic-with-kmap_local_page.patch mm-zswap-replace-kmap_atomic-with-kmap_local_page.patch mm-swapfile-replace-kmap_atomic-with-kmap_local_page.patch