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 59C5FC54EBE for ; Mon, 16 Jan 2023 20:06:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233203AbjAPUGb (ORCPT ); Mon, 16 Jan 2023 15:06:31 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57788 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233093AbjAPUGE (ORCPT ); Mon, 16 Jan 2023 15:06:04 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 45E62233C4 for ; Mon, 16 Jan 2023 12:06:03 -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 D5FBD6111C for ; Mon, 16 Jan 2023 20:06:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 38310C433D2; Mon, 16 Jan 2023 20:06:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1673899562; bh=bBTD5p4qR1ICuGsRwEfVy8aXzkuAWar11Fkp40O6hgA=; h=Date:To:From:Subject:From; b=Pc7vPARlPuxSyIH+qZwX/YYDa6Ou7qMAXIZtomfVlnYMdZYyoRzCpCOz89TUuDnu5 r/62A193ao6fBQupXgHcoFovNjNrBrgSvvP15UtM8vZ4pnRG+u9S5UJfCmGOMFat+Z u9ViBW+ZRWNYGBNPKG90rz5VDhPFFyoAHNHvZks0= Date: Mon, 16 Jan 2023 12:06:01 -0800 To: mm-commits@vger.kernel.org, willy@infradead.org, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-clean-up-mlock_page-munlock_page-references-in-comments.patch added to mm-unstable branch Message-Id: <20230116200602.38310C433D2@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: clean up mlock_page / munlock_page references in comments has been added to the -mm mm-unstable branch. Its filename is mm-clean-up-mlock_page-munlock_page-references-in-comments.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-clean-up-mlock_page-munlock_page-references-in-comments.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: "Matthew Wilcox (Oracle)" Subject: mm: clean up mlock_page / munlock_page references in comments Date: Mon, 16 Jan 2023 19:28:27 +0000 Change documentation and comments that refer to now-renamed functions. Link: https://lkml.kernel.org/r/20230116192827.2146732-5-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton --- --- a/Documentation/mm/unevictable-lru.rst~mm-clean-up-mlock_page-munlock_page-references-in-comments +++ a/Documentation/mm/unevictable-lru.rst @@ -298,7 +298,7 @@ treated as a no-op and mlock_fixup() sim If the VMA passes some filtering as described in "Filtering Special VMAs" below, mlock_fixup() will attempt to merge the VMA with its neighbors or split off a subset of the VMA if the range does not cover the entire VMA. Any pages -already present in the VMA are then marked as mlocked by mlock_page() via +already present in the VMA are then marked as mlocked by mlock_folio() via mlock_pte_range() via walk_page_range() via mlock_vma_pages_range(). Before returning from the system call, do_mlock() or mlockall() will call @@ -373,20 +373,21 @@ Because of the VMA filtering discussed a any "special" VMAs. So, those VMAs will be ignored for munlock. If the VMA is VM_LOCKED, mlock_fixup() again attempts to merge or split off the -specified range. All pages in the VMA are then munlocked by munlock_page() via +specified range. All pages in the VMA are then munlocked by munlock_folio() via mlock_pte_range() via walk_page_range() via mlock_vma_pages_range() - the same function used when mlocking a VMA range, with new flags for the VMA indicating that it is munlock() being performed. -munlock_page() uses the mlock pagevec to batch up work to be done under -lru_lock by __munlock_page(). __munlock_page() decrements the page's -mlock_count, and when that reaches 0 it clears PG_mlocked and clears -PG_unevictable, moving the page from unevictable state to inactive LRU. +munlock_folio() uses the mlock pagevec to batch up work to be done +under lru_lock by __munlock_folio(). __munlock_folio() decrements the +folio's mlock_count, and when that reaches 0 it clears the mlocked flag +and clears the unevictable flag, moving the folio from unevictable state +to the inactive LRU. -But in practice that may not work ideally: the page may not yet have reached +But in practice that may not work ideally: the folio may not yet have reached "the unevictable LRU", or it may have been temporarily isolated from it. In those cases its mlock_count field is unusable and must be assumed to be 0: so -that the page will be rescued to an evictable LRU, then perhaps be mlocked +that the folio will be rescued to an evictable LRU, then perhaps be mlocked again later if vmscan finds it in a VM_LOCKED VMA. @@ -489,15 +490,16 @@ For each PTE (or PMD) being unmapped fro munlock_vma_folio(), which calls munlock_folio() when the VMA is VM_LOCKED (unless it was a PTE mapping of a part of a transparent huge page). -munlock_page() uses the mlock pagevec to batch up work to be done under -lru_lock by __munlock_page(). __munlock_page() decrements the page's -mlock_count, and when that reaches 0 it clears PG_mlocked and clears -PG_unevictable, moving the page from unevictable state to inactive LRU. +munlock_folio() uses the mlock pagevec to batch up work to be done +under lru_lock by __munlock_folio(). __munlock_folio() decrements the +folio's mlock_count, and when that reaches 0 it clears the mlocked flag +and clears the unevictable flag, moving the folio from unevictable state +to the inactive LRU. -But in practice that may not work ideally: the page may not yet have reached +But in practice that may not work ideally: the folio may not yet have reached "the unevictable LRU", or it may have been temporarily isolated from it. In those cases its mlock_count field is unusable and must be assumed to be 0: so -that the page will be rescued to an evictable LRU, then perhaps be mlocked +that the folio will be rescued to an evictable LRU, then perhaps be mlocked again later if vmscan finds it in a VM_LOCKED VMA. --- a/mm/memory-failure.c~mm-clean-up-mlock_page-munlock_page-references-in-comments +++ a/mm/memory-failure.c @@ -2167,7 +2167,7 @@ try_again: } /* - * __munlock_pagevec may clear a writeback page's LRU flag without + * __munlock_folio() may clear a writeback page's LRU flag without * page_lock. We need wait writeback completion for this page or it * may trigger vfs BUG while evict inode. */ --- a/mm/swap.c~mm-clean-up-mlock_page-munlock_page-references-in-comments +++ a/mm/swap.c @@ -201,7 +201,7 @@ static void lru_add_fn(struct lruvec *lr * Is an smp_mb__after_atomic() still required here, before * folio_evictable() tests the mlocked flag, to rule out the possibility * of stranding an evictable folio on an unevictable LRU? I think - * not, because __munlock_page() only clears the mlocked flag + * not, because __munlock_folio() only clears the mlocked flag * while the LRU lock is held. * * (That is not true of __page_cache_release(), and not necessarily @@ -216,7 +216,7 @@ static void lru_add_fn(struct lruvec *lr folio_set_unevictable(folio); /* * folio->mlock_count = !!folio_test_mlocked(folio)? - * But that leaves __mlock_page() in doubt whether another + * But that leaves __mlock_folio() in doubt whether another * actor has already counted the mlock or not. Err on the * safe side, underestimate, let page reclaim fix it, rather * than leaving a page on the unevictable LRU indefinitely. _ Patches currently in -mm which might be from willy@infradead.org are buffer-add-b_folio-as-an-alias-of-b_page.patch buffer-replace-obvious-uses-of-b_page-with-b_folio.patch buffer-use-b_folio-in-touch_buffer.patch buffer-use-b_folio-in-end_buffer_async_read.patch buffer-use-b_folio-in-end_buffer_async_write.patch page_io-remove-buffer_head-include.patch buffer-use-b_folio-in-mark_buffer_dirty.patch gfs2-replace-obvious-uses-of-b_page-with-b_folio.patch jbd2-replace-obvious-uses-of-b_page-with-b_folio.patch nilfs2-replace-obvious-uses-of-b_page-with-b_folio.patch reiserfs-replace-obvious-uses-of-b_page-with-b_folio.patch mpage-use-b_folio-in-do_mpage_readpage.patch mm-memcg-add-folio_memcg_check.patch mm-remove-folio_pincount_ptr-and-head_compound_pincount.patch mm-convert-head_subpages_mapcount-into-folio_nr_pages_mapped.patch doc-clarify-refcount-section-by-referring-to-folios-pages.patch mm-convert-total_compound_mapcount-to-folio_total_mapcount.patch mm-convert-page_remove_rmap-to-use-a-folio-internally.patch mm-convert-page_add_anon_rmap-to-use-a-folio-internally.patch mm-convert-page_add_file_rmap-to-use-a-folio-internally.patch mm-add-folio_add_new_anon_rmap.patch mm-add-folio_add_new_anon_rmap-fix-2.patch page_alloc-use-folio-fields-directly.patch mm-use-a-folio-in-hugepage_add_anon_rmap-and-hugepage_add_new_anon_rmap.patch mm-use-entire_mapcount-in-__page_dup_rmap.patch mm-debug-remove-call-to-head_compound_mapcount.patch hugetlb-remove-uses-of-folio_mapcount_ptr.patch mm-convert-page_mapcount-to-use-folio_entire_mapcount.patch mm-remove-head_compound_mapcount-and-_ptr-functions.patch mm-reimplement-compound_order.patch mm-reimplement-compound_nr.patch mm-reimplement-compound_nr-fix.patch mm-convert-set_compound_page_dtor-and-set_compound_order-to-folios.patch mm-convert-is_transparent_hugepage-to-use-a-folio.patch mm-convert-destroy_large_folio-to-use-folio_dtor.patch hugetlb-remove-uses-of-compound_dtor-and-compound_nr.patch mm-remove-first-tail-page-members-from-struct-page.patch doc-correct-struct-folio-kernel-doc.patch mm-move-page-deferred_list-to-folio-_deferred_list.patch mm-huge_memory-remove-page_deferred_list.patch mm-huge_memory-convert-get_deferred_split_queue-to-take-a-folio.patch mm-convert-deferred_split_huge_page-to-deferred_split_folio.patch shmem-convert-shmem_write_end-to-use-a-folio.patch mm-add-vma_alloc_zeroed_movable_folio.patch mm-convert-do_anonymous_page-to-use-a-folio.patch mm-convert-wp_page_copy-to-use-folios.patch mm-use-a-folio-in-copy_pte_range.patch mm-use-a-folio-in-copy_present_pte.patch mm-fs-convert-inode_attach_wb-to-take-a-folio.patch mm-convert-mem_cgroup_css_from_page-to-mem_cgroup_css_from_folio.patch mm-remove-page_evictable.patch mm-remove-mlock_vma_page.patch mm-remove-munlock_vma_page.patch mm-clean-up-mlock_page-munlock_page-references-in-comments.patch