+ mm-remove-first-tail-page-members-from-struct-page.patch added to mm-unstable branch

+ mm-remove-first-tail-page-members-from-struct-page.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: mm: remove 'First tail page' members from struct page
has been added to the -mm mm-unstable branch.  Its filename is
     mm-remove-first-tail-page-members-from-struct-page.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-remove-first-tail-page-members-from-struct-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: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Subject: mm: remove 'First tail page' members from struct page
Date: Wed, 11 Jan 2023 14:29:08 +0000

All former users now use the folio equivalents, so remove them from the
definition of struct page.

Link: https://lkml.kernel.org/r/20230111142915.1001531-23-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/mm_types.h |   18 ------------------
 kernel/crash_core.c      |    4 ++--
 2 files changed, 2 insertions(+), 20 deletions(-)

--- a/include/linux/mm_types.h~mm-remove-first-tail-page-members-from-struct-page
+++ a/include/linux/mm_types.h
@@ -140,16 +140,6 @@ struct page {
 		};
 		struct {	/* Tail pages of compound page */
 			unsigned long compound_head;	/* Bit zero is set */
-
-			/* First tail page only */
-			unsigned char compound_dtor;
-			unsigned char compound_order;
-			atomic_t compound_mapcount;
-			atomic_t subpages_mapcount;
-			atomic_t compound_pincount;
-#ifdef CONFIG_64BIT
-			unsigned int compound_nr; /* 1 << compound_order */
-#endif
 		};
 		struct {	/* Second tail page of transparent huge page */
 			unsigned long _compound_pad_1;	/* compound_head */
@@ -401,14 +391,6 @@ FOLIO_MATCH(memcg_data, memcg_data);
 			offsetof(struct page, pg) + sizeof(struct page))
 FOLIO_MATCH(flags, _flags_1);
 FOLIO_MATCH(compound_head, _head_1);
-FOLIO_MATCH(compound_dtor, _folio_dtor);
-FOLIO_MATCH(compound_order, _folio_order);
-FOLIO_MATCH(compound_mapcount, _entire_mapcount);
-FOLIO_MATCH(subpages_mapcount, _nr_pages_mapped);
-FOLIO_MATCH(compound_pincount, _pincount);
-#ifdef CONFIG_64BIT
-FOLIO_MATCH(compound_nr, _folio_nr_pages);
-#endif
 #undef FOLIO_MATCH
 #define FOLIO_MATCH(pg, fl)						\
 	static_assert(offsetof(struct folio, fl) ==			\
--- a/kernel/crash_core.c~mm-remove-first-tail-page-members-from-struct-page
+++ a/kernel/crash_core.c
@@ -455,8 +455,8 @@ static int __init crash_save_vmcoreinfo_
 	VMCOREINFO_OFFSET(page, lru);
 	VMCOREINFO_OFFSET(page, _mapcount);
 	VMCOREINFO_OFFSET(page, private);
-	VMCOREINFO_OFFSET(page, compound_dtor);
-	VMCOREINFO_OFFSET(page, compound_order);
+	VMCOREINFO_OFFSET(folio, _folio_dtor);
+	VMCOREINFO_OFFSET(folio, _folio_order);
 	VMCOREINFO_OFFSET(page, compound_head);
 	VMCOREINFO_OFFSET(pglist_data, node_zones);
 	VMCOREINFO_OFFSET(pglist_data, nr_zones);
_

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
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-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