From patchwork Tue Mar 22 21:45:38 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 12789224 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id DF2B3C433EF for ; Tue, 22 Mar 2022 21:45:42 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 783526B013C; Tue, 22 Mar 2022 17:45:42 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 731376B013D; Tue, 22 Mar 2022 17:45:42 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 584A86B013E; Tue, 22 Mar 2022 17:45:42 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.a.hostedemail.com [64.99.140.24]) by kanga.kvack.org (Postfix) with ESMTP id 488B46B013C for ; Tue, 22 Mar 2022 17:45:42 -0400 (EDT) Received: from smtpin07.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 1C61124293 for ; Tue, 22 Mar 2022 21:45:42 +0000 (UTC) X-FDA: 79273354524.07.1D9A40C Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by imf03.hostedemail.com (Postfix) with ESMTP id 6D8F920033 for ; Tue, 22 Mar 2022 21:45:41 +0000 (UTC) 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 5CDFDB81DAD; Tue, 22 Mar 2022 21:45:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 03621C340EE; Tue, 22 Mar 2022 21:45:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1647985539; bh=EioTn1AYwKLEaPNTWCWOFb/pRNMlD4WN2TI+GFaUeJ8=; h=Date:To:From:In-Reply-To:Subject:From; b=p96dNi2j6jLI67sQUAX7c5LC5z00zLvjrTTSJuis3p7GDjDQztcYow2qy+ILvXOiy Wr3ydweFPqsnu5NvRROkN3vX3mbGYt4TFL7ecbrUyui3Ti6WnV8V0hBYTiEbgJDuFn z87ieqAjqZ6WzTyqOgi44uQxT8LCRANCrsyGbi6U= Date: Tue, 22 Mar 2022 14:45:38 -0700 To: willy@infradead.org,neilb@suse.de,jack@suse.de,djwong@kernel.org,david@fromorbit.com,hughd@google.com,akpm@linux-foundation.org,patches@lists.linux.dev,linux-mm@kvack.org,mm-commits@vger.kernel.org,torvalds@linux-foundation.org,akpm@linux-foundation.org From: Andrew Morton In-Reply-To: <20220322143803.04a5e59a07e48284f196a2f9@linux-foundation.org> Subject: [patch 140/227] mm/fs: delete PF_SWAPWRITE Message-Id: <20220322214539.03621C340EE@smtp.kernel.org> X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 6D8F920033 X-Rspam-User: Authentication-Results: imf03.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=p96dNi2j; dmarc=none; spf=pass (imf03.hostedemail.com: domain of akpm@linux-foundation.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org X-Stat-Signature: fjywywj7f6ii9ikcejxgz5yz4mz4qhpd X-HE-Tag: 1647985541-591927 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Hugh Dickins Subject: mm/fs: delete PF_SWAPWRITE PF_SWAPWRITE has been redundant since v3.2 commit ee72886d8ed5 ("mm: vmscan: do not writeback filesystem pages in direct reclaim"). Coincidentally, NeilBrown's current patch "remove inode_congested()" deletes may_write_to_inode(), which appeared to be the one function which took notice of PF_SWAPWRITE. But if you study the old logic, and the conditions under which may_write_to_inode() was called, you discover that flag and function have been pointless for a decade. Link: https://lkml.kernel.org/r/75e80e7-742d-e3bd-531-614db8961e4@google.com Signed-off-by: Hugh Dickins Cc: NeilBrown Cc: Jan Kara Cc: "Darrick J. Wong" Cc: Dave Chinner Cc: Matthew Wilcox Signed-off-by: Andrew Morton --- fs/fs-writeback.c | 3 --- fs/xfs/libxfs/xfs_btree.c | 2 +- include/linux/sched.h | 1 - mm/migrate.c | 7 ------- mm/vmscan.c | 8 ++------ 5 files changed, 3 insertions(+), 18 deletions(-) --- a/fs/fs-writeback.c~mm-fs-delete-pf_swapwrite +++ a/fs/fs-writeback.c @@ -2197,7 +2197,6 @@ void wb_workfn(struct work_struct *work) long pages_written; set_worker_desc("flush-%s", bdi_dev_name(wb->bdi)); - current->flags |= PF_SWAPWRITE; if (likely(!current_is_workqueue_rescuer() || !test_bit(WB_registered, &wb->state))) { @@ -2226,8 +2225,6 @@ void wb_workfn(struct work_struct *work) wb_wakeup(wb); else if (wb_has_dirty_io(wb) && dirty_writeback_interval) wb_wakeup_delayed(wb); - - current->flags &= ~PF_SWAPWRITE; } /* --- a/fs/xfs/libxfs/xfs_btree.c~mm-fs-delete-pf_swapwrite +++ a/fs/xfs/libxfs/xfs_btree.c @@ -2818,7 +2818,7 @@ xfs_btree_split_worker( * in any way. */ if (args->kswapd) - new_pflags |= PF_MEMALLOC | PF_SWAPWRITE | PF_KSWAPD; + new_pflags |= PF_MEMALLOC | PF_KSWAPD; current_set_flags_nested(&pflags, new_pflags); xfs_trans_set_context(args->cur->bc_tp); --- a/include/linux/sched.h~mm-fs-delete-pf_swapwrite +++ a/include/linux/sched.h @@ -1689,7 +1689,6 @@ extern struct pid *cad_pid; * I am cleaning dirty pages from some other bdi. */ #define PF_KTHREAD 0x00200000 /* I am a kernel thread */ #define PF_RANDOMIZE 0x00400000 /* Randomize virtual address space */ -#define PF_SWAPWRITE 0x00800000 /* Allowed to write to swap */ #define PF_NO_SETAFFINITY 0x04000000 /* Userland is not allowed to meddle with cpus_mask */ #define PF_MCE_EARLY 0x08000000 /* Early kill for mce process policy */ #define PF_MEMALLOC_PIN 0x10000000 /* Allocation context constrained to zones which allow long term pinning. */ --- a/mm/migrate.c~mm-fs-delete-pf_swapwrite +++ a/mm/migrate.c @@ -1350,7 +1350,6 @@ int migrate_pages(struct list_head *from bool is_thp = false; struct page *page; struct page *page2; - int swapwrite = current->flags & PF_SWAPWRITE; int rc, nr_subpages; LIST_HEAD(ret_pages); LIST_HEAD(thp_split_pages); @@ -1359,9 +1358,6 @@ int migrate_pages(struct list_head *from trace_mm_migrate_pages_start(mode, reason); - if (!swapwrite) - current->flags |= PF_SWAPWRITE; - thp_subpage_migration: for (pass = 0; pass < 10 && (retry || thp_retry); pass++) { retry = 0; @@ -1516,9 +1512,6 @@ out: trace_mm_migrate_pages(nr_succeeded, nr_failed_pages, nr_thp_succeeded, nr_thp_failed, nr_thp_split, mode, reason); - if (!swapwrite) - current->flags &= ~PF_SWAPWRITE; - if (ret_succeeded) *ret_succeeded = nr_succeeded; --- a/mm/vmscan.c~mm-fs-delete-pf_swapwrite +++ a/mm/vmscan.c @@ -4457,7 +4457,7 @@ static int kswapd(void *p) * us from recursively trying to free more memory as we're * trying to free the first piece of memory in the first place). */ - tsk->flags |= PF_MEMALLOC | PF_SWAPWRITE | PF_KSWAPD; + tsk->flags |= PF_MEMALLOC | PF_KSWAPD; set_freezable(); WRITE_ONCE(pgdat->kswapd_order, 0); @@ -4508,7 +4508,7 @@ kswapd_try_sleep: goto kswapd_try_sleep; } - tsk->flags &= ~(PF_MEMALLOC | PF_SWAPWRITE | PF_KSWAPD); + tsk->flags &= ~(PF_MEMALLOC | PF_KSWAPD); return 0; } @@ -4749,11 +4749,8 @@ static int __node_reclaim(struct pglist_ fs_reclaim_acquire(sc.gfp_mask); /* * We need to be able to allocate from the reserves for RECLAIM_UNMAP - * and we also need to be able to write out pages for RECLAIM_WRITE - * and RECLAIM_UNMAP. */ noreclaim_flag = memalloc_noreclaim_save(); - p->flags |= PF_SWAPWRITE; set_task_reclaim_state(p, &sc.reclaim_state); if (node_pagecache_reclaimable(pgdat) > pgdat->min_unmapped_pages) { @@ -4767,7 +4764,6 @@ static int __node_reclaim(struct pglist_ } set_task_reclaim_state(p, NULL); - current->flags &= ~PF_SWAPWRITE; memalloc_noreclaim_restore(noreclaim_flag); fs_reclaim_release(sc.gfp_mask); psi_memstall_leave(&pflags);