Makes dept able to track PG_writeback waits and events, which will be
useful in practice.

Signed-off-by: Byungchul Park <[email protected]>
---
 include/linux/mm_types.h   | 1 +
 include/linux/page-flags.h | 7 +++++++
 mm/filemap.c               | 6 +++++-
 mm/mm_init.c               | 1 +
 4 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 85d06073d37b..fa6ba4196e0d 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -222,6 +222,7 @@ struct page {
 #endif
        struct dept_page_usage usage;
        struct dept_ext_wgen pg_locked_wgen;
+       struct dept_ext_wgen pg_writeback_wgen;
 } _struct_page_alignment;
 
 /*
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 0b0655354b08..ec736811a2c6 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -203,6 +203,7 @@ enum pageflags {
 #include <linux/dept.h>
 
 extern struct dept_map pg_locked_map;
+extern struct dept_map pg_writeback_map;
 
 static inline void dept_set_page_usage(struct page *p,
                unsigned int new_type)
@@ -292,6 +293,8 @@ static inline void dept_page_set_bit(struct page *p, int 
bit_nr)
 
        if (bit_nr == PG_locked)
                dept_request_event(&pg_locked_map, &p->pg_locked_wgen);
+       else if (bit_nr == PG_writeback)
+               dept_request_event(&pg_writeback_map, &p->pg_writeback_wgen);
 }
 
 static inline void dept_page_clear_bit(struct page *p, int bit_nr)
@@ -300,6 +303,8 @@ static inline void dept_page_clear_bit(struct page *p, int 
bit_nr)
 
        if (bit_nr == PG_locked)
                dept_event(&pg_locked_map, evt_f, _RET_IP_, __func__, 
&p->pg_locked_wgen);
+       else if (bit_nr == PG_writeback)
+               dept_event(&pg_writeback_map, evt_f, _RET_IP_, __func__, 
&p->pg_writeback_wgen);
 }
 
 static inline void dept_page_wait_on_bit(struct page *p, int bit_nr)
@@ -311,6 +316,8 @@ static inline void dept_page_wait_on_bit(struct page *p, 
int bit_nr)
 
        if (bit_nr == PG_locked)
                dept_wait(&pg_locked_map, evt_f, _RET_IP_, __func__, 0, -1L);
+       else if (bit_nr == PG_writeback)
+               dept_wait(&pg_writeback_map, evt_f, _RET_IP_, __func__, 0, -1L);
 }
 
 static inline void dept_folio_set_bit(struct folio *f, int bit_nr)
diff --git a/mm/filemap.c b/mm/filemap.c
index d7e567af3261..0ce3f9307582 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1191,7 +1191,7 @@ static void folio_wake_bit(struct folio *folio, int 
bit_nr)
         * dept_page_clear_bit() being called multiple times is harmless.
         * The worst case is to miss some dependencies but it's okay.
         */
-       if (bit_nr == PG_locked)
+       if (bit_nr == PG_locked || bit_nr == PG_writeback)
                dept_page_clear_bit(&folio->page, bit_nr);
 
        spin_lock_irqsave(&q->lock, flags);
@@ -1248,6 +1248,9 @@ static inline bool folio_trylock_flag(struct folio 
*folio, int bit_nr,
 struct dept_map __maybe_unused pg_locked_map = 
DEPT_MAP_INITIALIZER(pg_locked_map, NULL);
 EXPORT_SYMBOL(pg_locked_map);
 
+struct dept_map __maybe_unused pg_writeback_map = 
DEPT_MAP_INITIALIZER(pg_writeback_map, NULL);
+EXPORT_SYMBOL(pg_writeback_map);
+
 static inline int folio_wait_bit_common(struct folio *folio, int bit_nr,
                int state, enum behavior behavior)
 {
@@ -1686,6 +1689,7 @@ void folio_end_writeback_no_dropbehind(struct folio 
*folio)
                folio_rotate_reclaimable(folio);
        }
 
+       dept_page_clear_bit(&folio->page, PG_writeback);
        if (__folio_end_writeback(folio))
                folio_wake_bit(folio, PG_writeback);
 
diff --git a/mm/mm_init.c b/mm/mm_init.c
index f1d3e4afd43b..9f99eeb99ca3 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -589,6 +589,7 @@ void __meminit __init_single_page(struct page *page, 
unsigned long pfn,
        page_cpupid_reset_last(page);
        page_kasan_tag_reset(page);
        dept_ext_wgen_init(&page->pg_locked_wgen);
+       dept_ext_wgen_init(&page->pg_writeback_wgen);
 
        INIT_LIST_HEAD(&page->lru);
 #ifdef WANT_PAGE_VIRTUAL
-- 
2.17.1


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