Makes dept able to track PG_locked waits and events, which will be useful in practice. See the following link that shows dept worked with PG_locked and detected real issues in practice:
https://lore.kernel.org/lkml/1674268856-31807-1-git-send-email-byungchul.p...@lge.com/ Signed-off-by: Byungchul Park <byungc...@sk.com> --- include/linux/mm_types.h | 2 + include/linux/page-flags.h | 125 +++++++++++++++++++++++++++++++++---- include/linux/pagemap.h | 16 ++++- mm/filemap.c | 26 ++++++++ mm/mm_init.c | 2 + 5 files changed, 158 insertions(+), 13 deletions(-) diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 56d07edd01f9..7e9d63cef28a 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -20,6 +20,7 @@ #include <linux/seqlock.h> #include <linux/percpu_counter.h> #include <linux/types.h> +#include <linux/dept.h> #include <asm/mmu.h> @@ -224,6 +225,7 @@ struct page { struct page *kmsan_shadow; struct page *kmsan_origin; #endif + struct dept_ext_wgen pg_locked_wgen; } _struct_page_alignment; /* diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index e6a21b62dcce..73cb8a1ad4f3 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -194,6 +194,61 @@ enum pageflags { #ifndef __GENERATING_BOUNDS_H +#ifdef CONFIG_DEPT +#include <linux/kernel.h> +#include <linux/dept.h> + +extern struct dept_map pg_locked_map; + +/* + * Place the following annotations in its suitable point in code: + * + * Annotate dept_page_set_bit() around firstly set_bit*() + * Annotate dept_page_clear_bit() around clear_bit*() + * Annotate dept_page_wait_on_bit() around wait_on_bit*() + */ + +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); +} + +static inline void dept_page_clear_bit(struct page *p, int bit_nr) +{ + if (bit_nr == PG_locked) + dept_event(&pg_locked_map, 1UL, _RET_IP_, __func__, &p->pg_locked_wgen); +} + +static inline void dept_page_wait_on_bit(struct page *p, int bit_nr) +{ + if (bit_nr == PG_locked) + dept_wait(&pg_locked_map, 1UL, _RET_IP_, __func__, 0, -1L); +} + +static inline void dept_folio_set_bit(struct folio *f, int bit_nr) +{ + dept_page_set_bit(&f->page, bit_nr); +} + +static inline void dept_folio_clear_bit(struct folio *f, int bit_nr) +{ + dept_page_clear_bit(&f->page, bit_nr); +} + +static inline void dept_folio_wait_on_bit(struct folio *f, int bit_nr) +{ + dept_page_wait_on_bit(&f->page, bit_nr); +} +#else +#define dept_page_set_bit(p, bit_nr) do { } while (0) +#define dept_page_clear_bit(p, bit_nr) do { } while (0) +#define dept_page_wait_on_bit(p, bit_nr) do { } while (0) +#define dept_folio_set_bit(f, bit_nr) do { } while (0) +#define dept_folio_clear_bit(f, bit_nr) do { } while (0) +#define dept_folio_wait_on_bit(f, bit_nr) do { } while (0) +#endif + #ifdef CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP DECLARE_STATIC_KEY_FALSE(hugetlb_optimize_vmemmap_key); @@ -415,27 +470,51 @@ static __always_inline bool folio_test_##name(const struct folio *folio) \ #define FOLIO_SET_FLAG(name, page) \ static __always_inline void folio_set_##name(struct folio *folio) \ -{ set_bit(PG_##name, folio_flags(folio, page)); } +{ \ + set_bit(PG_##name, folio_flags(folio, page)); \ + dept_folio_set_bit(folio, PG_##name); \ +} #define FOLIO_CLEAR_FLAG(name, page) \ static __always_inline void folio_clear_##name(struct folio *folio) \ -{ clear_bit(PG_##name, folio_flags(folio, page)); } +{ \ + clear_bit(PG_##name, folio_flags(folio, page)); \ + dept_folio_clear_bit(folio, PG_##name); \ +} #define __FOLIO_SET_FLAG(name, page) \ static __always_inline void __folio_set_##name(struct folio *folio) \ -{ __set_bit(PG_##name, folio_flags(folio, page)); } +{ \ + __set_bit(PG_##name, folio_flags(folio, page)); \ + dept_folio_set_bit(folio, PG_##name); \ +} #define __FOLIO_CLEAR_FLAG(name, page) \ static __always_inline void __folio_clear_##name(struct folio *folio) \ -{ __clear_bit(PG_##name, folio_flags(folio, page)); } +{ \ + __clear_bit(PG_##name, folio_flags(folio, page)); \ + dept_folio_clear_bit(folio, PG_##name); \ +} #define FOLIO_TEST_SET_FLAG(name, page) \ static __always_inline bool folio_test_set_##name(struct folio *folio) \ -{ return test_and_set_bit(PG_##name, folio_flags(folio, page)); } +{ \ + bool __ret = test_and_set_bit(PG_##name, folio_flags(folio, page)); \ + \ + if (!__ret) \ + dept_folio_set_bit(folio, PG_##name); \ + return __ret; \ +} #define FOLIO_TEST_CLEAR_FLAG(name, page) \ static __always_inline bool folio_test_clear_##name(struct folio *folio) \ -{ return test_and_clear_bit(PG_##name, folio_flags(folio, page)); } +{ \ + bool __ret = test_and_clear_bit(PG_##name, folio_flags(folio, page)); \ + \ + if (__ret) \ + dept_folio_clear_bit(folio, PG_##name); \ + return __ret; \ +} #define FOLIO_FLAG(name, page) \ FOLIO_TEST_FLAG(name, page) \ @@ -450,32 +529,54 @@ static __always_inline int Page##uname(const struct page *page) \ #define SETPAGEFLAG(uname, lname, policy) \ FOLIO_SET_FLAG(lname, FOLIO_##policy) \ static __always_inline void SetPage##uname(struct page *page) \ -{ set_bit(PG_##lname, &policy(page, 1)->flags); } +{ \ + set_bit(PG_##lname, &policy(page, 1)->flags); \ + dept_page_set_bit(page, PG_##lname); \ +} #define CLEARPAGEFLAG(uname, lname, policy) \ FOLIO_CLEAR_FLAG(lname, FOLIO_##policy) \ static __always_inline void ClearPage##uname(struct page *page) \ -{ clear_bit(PG_##lname, &policy(page, 1)->flags); } +{ \ + clear_bit(PG_##lname, &policy(page, 1)->flags); \ + dept_page_clear_bit(page, PG_##lname); \ +} #define __SETPAGEFLAG(uname, lname, policy) \ __FOLIO_SET_FLAG(lname, FOLIO_##policy) \ static __always_inline void __SetPage##uname(struct page *page) \ -{ __set_bit(PG_##lname, &policy(page, 1)->flags); } +{ \ + __set_bit(PG_##lname, &policy(page, 1)->flags); \ + dept_page_set_bit(page, PG_##lname); \ +} #define __CLEARPAGEFLAG(uname, lname, policy) \ __FOLIO_CLEAR_FLAG(lname, FOLIO_##policy) \ static __always_inline void __ClearPage##uname(struct page *page) \ -{ __clear_bit(PG_##lname, &policy(page, 1)->flags); } +{ \ + __clear_bit(PG_##lname, &policy(page, 1)->flags); \ + dept_page_clear_bit(page, PG_##lname); \ +} #define TESTSETFLAG(uname, lname, policy) \ FOLIO_TEST_SET_FLAG(lname, FOLIO_##policy) \ static __always_inline int TestSetPage##uname(struct page *page) \ -{ return test_and_set_bit(PG_##lname, &policy(page, 1)->flags); } +{ \ + bool ret = test_and_set_bit(PG_##lname, &policy(page, 1)->flags);\ + if (!ret) \ + dept_page_set_bit(page, PG_##lname); \ + return ret; \ +} #define TESTCLEARFLAG(uname, lname, policy) \ FOLIO_TEST_CLEAR_FLAG(lname, FOLIO_##policy) \ static __always_inline int TestClearPage##uname(struct page *page) \ -{ return test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); } +{ \ + bool ret = test_and_clear_bit(PG_##lname, &policy(page, 1)->flags);\ + if (ret) \ + dept_page_clear_bit(page, PG_##lname); \ + return ret; \ +} #define PAGEFLAG(uname, lname, policy) \ TESTPAGEFLAG(uname, lname, policy) \ diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 26baa78f1ca7..c4c9742c7a29 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -1097,7 +1097,12 @@ void folio_unlock(struct folio *folio); */ static inline bool folio_trylock(struct folio *folio) { - return likely(!test_and_set_bit_lock(PG_locked, folio_flags(folio, 0))); + bool ret = !test_and_set_bit_lock(PG_locked, folio_flags(folio, 0)); + + if (ret) + dept_page_set_bit(&folio->page, PG_locked); + + return likely(ret); } /* @@ -1133,6 +1138,15 @@ static inline bool trylock_page(struct page *page) static inline void folio_lock(struct folio *folio) { might_sleep(); + /* + * dept_page_wait_on_bit() will be called if __folio_lock() goes + * through a real wait path. However, for better job to detect + * *potential* deadlocks, let's assume that folio_lock() always + * goes through wait so that dept can take into account all the + * potential cases. + */ + dept_page_wait_on_bit(&folio->page, PG_locked); + if (!folio_trylock(folio)) __folio_lock(folio); } diff --git a/mm/filemap.c b/mm/filemap.c index 7b90cbeb4a1a..cab03b41add2 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -48,6 +48,7 @@ #include <linux/rcupdate_wait.h> #include <linux/sched/mm.h> #include <linux/sysctl.h> +#include <linux/dept.h> #include <asm/pgalloc.h> #include <asm/tlbflush.h> #include "internal.h" @@ -1145,6 +1146,7 @@ static int wake_page_function(wait_queue_entry_t *wait, unsigned mode, int sync, if (flags & WQ_FLAG_CUSTOM) { if (test_and_set_bit(key->bit_nr, &key->folio->flags)) return -1; + dept_page_set_bit(&key->folio->page, key->bit_nr); flags |= WQ_FLAG_DONE; } } @@ -1228,6 +1230,7 @@ static inline bool folio_trylock_flag(struct folio *folio, int bit_nr, if (wait->flags & WQ_FLAG_EXCLUSIVE) { if (test_and_set_bit(bit_nr, &folio->flags)) return false; + dept_page_set_bit(&folio->page, bit_nr); } else if (test_bit(bit_nr, &folio->flags)) return false; @@ -1235,6 +1238,9 @@ static inline bool folio_trylock_flag(struct folio *folio, int bit_nr, return true; } +struct dept_map __maybe_unused pg_locked_map = DEPT_MAP_INITIALIZER(pg_locked_map, NULL); +EXPORT_SYMBOL(pg_locked_map); + static inline int folio_wait_bit_common(struct folio *folio, int bit_nr, int state, enum behavior behavior) { @@ -1246,6 +1252,8 @@ static inline int folio_wait_bit_common(struct folio *folio, int bit_nr, unsigned long pflags; bool in_thrashing; + dept_page_wait_on_bit(&folio->page, bit_nr); + if (bit_nr == PG_locked && !folio_test_uptodate(folio) && folio_test_workingset(folio)) { delayacct_thrashing_start(&in_thrashing); @@ -1339,6 +1347,23 @@ static inline int folio_wait_bit_common(struct folio *folio, int bit_nr, break; } + /* + * dept_page_set_bit() might have been called already in + * folio_trylock_flag(), wake_page_function() or somewhere. + * However, call it again to reset the wgen of dept to ensure + * dept_page_wait_on_bit() is called prior to + * dept_page_set_bit(). + * + * Remind dept considers all the waits between + * dept_page_set_bit() and dept_page_clear_bit() as potential + * event disturbers. Ensure the correct sequence so that dept + * can make correct decisions: + * + * wait -> acquire(set bit) -> release(clear bit) + */ + if (wait->flags & WQ_FLAG_DONE) + dept_page_set_bit(&folio->page, bit_nr); + /* * If a signal happened, this 'finish_wait()' may remove the last * waiter from the wait-queues, but the folio waiters bit will remain @@ -1496,6 +1521,7 @@ void folio_unlock(struct folio *folio) BUILD_BUG_ON(PG_waiters != 7); BUILD_BUG_ON(PG_locked > 7); VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); + dept_page_clear_bit(&folio->page, PG_locked); if (folio_xor_flags_has_waiters(folio, 1 << PG_locked)) folio_wake_bit(folio, PG_locked); } diff --git a/mm/mm_init.c b/mm/mm_init.c index 327764ca0ee4..39cf0bc355ba 100644 --- a/mm/mm_init.c +++ b/mm/mm_init.c @@ -31,6 +31,7 @@ #include <linux/execmem.h> #include <linux/vmstat.h> #include <linux/hugetlb.h> +#include <linux/dept.h> #include "internal.h" #include "slab.h" #include "shuffle.h" @@ -586,6 +587,7 @@ void __meminit __init_single_page(struct page *page, unsigned long pfn, atomic_set(&page->_mapcount, -1); page_cpupid_reset_last(page); page_kasan_tag_reset(page); + dept_ext_wgen_init(&page->pg_locked_wgen); INIT_LIST_HEAD(&page->lru); #ifdef WANT_PAGE_VIRTUAL -- 2.17.1
