diff mbox series

[v8,25/25] dept: Track the potential waits of PG_{locked,writeback}

Message ID 1674782358-25542-26-git-send-email-max.byungchul.park@gmail.com (mailing list archive)
State New
Headers show
Series DEPT(Dependency Tracker) | expand

Commit Message

Byungchul Park Jan. 27, 2023, 1:19 a.m. UTC 
Currently, Dept only tracks the real waits of PG_{locked,writeback} that
actually happened having gone through __schedule() to avoid false
positives. However, it ends in limited capacity for deadlock detection,
because anyway there might be still way more potential dependencies by
the waits that have yet to happen but may happen in the future so as to
cause a deadlock.

So let Dept assume that when PG_{locked,writeback} bit gets cleared,
there might be waits on the bit to be woken up.

Even though false positives may increase with the aggressive tracking,
it's worth doing it because it's going to be useful in practice. See the
following link for instance:

   https://lore.kernel.org/lkml/1674268856-31807-1-git-send-email-byungchul.park@lge.com/

Signed-off-by: Byungchul Park <max.byungchul.park@gmail.com>
---
 include/linux/mm_types.h   |   3 ++
 include/linux/page-flags.h | 112 ++++++++++++++++++++++++++++++++++++++++-----
 include/linux/pagemap.h    |   7 ++-
 mm/filemap.c               |   9 +++-
 mm/page_alloc.c            |   3 ++
 5 files changed, 119 insertions(+), 15 deletions(-)

Comments

kernel test robot Jan. 28, 2023, 8:30 p.m. UTC | #1 
Hi Byungchul,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on tip/locking/core]
[also build test ERROR on tip/sched/core drm-misc/drm-misc-next linus/master v6.2-rc5 next-20230127]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Byungchul-Park/llist-Move-llist_-head-node-definition-to-types-h/20230128-102456
patch link:    https://lore.kernel.org/r/1674782358-25542-26-git-send-email-max.byungchul.park%40gmail.com
patch subject: [PATCH v8 25/25] dept: Track the potential waits of PG_{locked,writeback}
config: s390-allmodconfig (https://download.01.org/0day-ci/archive/20230129/202301290402.j3poWc84-lkp@intel.com/config)
compiler: s390-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/ba934a05473c5212edeff20f2298a249bfe87351
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Byungchul-Park/llist-Move-llist_-head-node-definition-to-types-h/20230128-102456
        git checkout ba934a05473c5212edeff20f2298a249bfe87351
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=s390 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=s390 SHELL=/bin/bash

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>, old ones prefixed by <<):

>> ERROR: modpost: "PG_locked_map" [mm/zsmalloc.ko] undefined!
>> ERROR: modpost: "PG_locked_map" [mm/z3fold.ko] undefined!
>> ERROR: modpost: "PG_locked_map" [fs/reiserfs/reiserfs.ko] undefined!
>> ERROR: modpost: "PG_locked_map" [fs/ext4/ext4.ko] undefined!
>> ERROR: modpost: "PG_locked_map" [fs/ext2/ext2.ko] undefined!
>> ERROR: modpost: "PG_locked_map" [fs/jbd2/jbd2.ko] undefined!
>> ERROR: modpost: "PG_locked_map" [fs/minix/minix.ko] undefined!
>> ERROR: modpost: "PG_locked_map" [fs/ecryptfs/ecryptfs.ko] undefined!
>> ERROR: modpost: "PG_locked_map" [fs/nfs/nfs.ko] undefined!
>> ERROR: modpost: "PG_locked_map" [fs/sysv/sysv.ko] undefined!
WARNING: modpost: suppressed 44 unresolved symbol warnings because there were too many)
diff mbox series

Patch

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 3b84750..61d982e 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -19,6 +19,7 @@ 
 #include <linux/workqueue.h>
 #include <linux/seqlock.h>
 #include <linux/percpu_counter.h>
+#include <linux/dept.h>
 
 #include <asm/mmu.h>
 
@@ -252,6 +253,8 @@  struct page {
 #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
 	int _last_cpupid;
 #endif
+	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 69e93a0..d6ca114 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -202,6 +202,50 @@  enum pageflags {
 
 #ifndef __GENERATING_BOUNDS_H
 
+#ifdef CONFIG_DEPT
+#include <linux/kernel.h>
+#include <linux/dept.h>
+
+extern struct dept_map PG_locked_map;
+extern struct dept_map PG_writeback_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);
+	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)
+{
+	if (bit_nr == PG_locked)
+		dept_event(&PG_locked_map, 1UL, _RET_IP_, __func__, &p->PG_locked_wgen);
+	else if (bit_nr == PG_writeback)
+		dept_event(&PG_writeback_map, 1UL, _RET_IP_, __func__, &p->PG_writeback_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);
+	else if (bit_nr == PG_writeback)
+		dept_wait(&PG_writeback_map, 1UL, _RET_IP_, __func__, 0, -1L);
+}
+#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)
+#endif
+
 #ifdef CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
 DECLARE_STATIC_KEY_FALSE(hugetlb_optimize_vmemmap_key);
 
@@ -383,44 +427,88 @@  static unsigned long *folio_flags(struct folio *folio, unsigned n)
 #define SETPAGEFLAG(uname, lname, policy)				\
 static __always_inline							\
 void folio_set_##lname(struct folio *folio)				\
-{ set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); }		\
+{									\
+	set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy));	\
+	dept_page_set_bit(&folio->page, PG_##lname);			\
+}									\
 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)				\
 static __always_inline							\
 void folio_clear_##lname(struct folio *folio)				\
-{ clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); }		\
+{									\
+	clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy));	\
+	dept_page_clear_bit(&folio->page, PG_##lname);			\
+}									\
 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)				\
 static __always_inline							\
 void __folio_set_##lname(struct folio *folio)				\
-{ __set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); }		\
+{									\
+	__set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy));	\
+	dept_page_set_bit(&folio->page, PG_##lname);			\
+}									\
 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)				\
 static __always_inline							\
 void __folio_clear_##lname(struct folio *folio)				\
-{ __clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); }	\
+{									\
+	__clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy));	\
+	dept_page_clear_bit(&folio->page, PG_##lname);			\
+}									\
 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)				\
 static __always_inline							\
 bool folio_test_set_##lname(struct folio *folio)			\
-{ return test_and_set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
+{									\
+	bool ret = test_and_set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy));\
+	if (!ret)							\
+		dept_page_set_bit(&folio->page, PG_##lname);		\
+	return ret;							\
+}									\
 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)				\
 static __always_inline							\
 bool folio_test_clear_##lname(struct folio *folio)			\
-{ return test_and_clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
+{									\
+	bool ret = test_and_clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy));\
+	if (ret)							\
+		dept_page_clear_bit(&folio->page, PG_##lname);		\
+	return ret;							\
+}									\
 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 29e1f9e..2843619 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -898,7 +898,12 @@  bool __folio_lock_or_retry(struct folio *folio, struct mm_struct *mm,
  */
 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);
 }
 
 /*
diff --git a/mm/filemap.c b/mm/filemap.c
index adc49cb..03a3c91 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1097,6 +1097,7 @@  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;
 		}
 	}
@@ -1206,6 +1207,7 @@  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;
 
@@ -1216,8 +1218,8 @@  static inline bool folio_trylock_flag(struct folio *folio, int bit_nr,
 /* How many times do we accept lock stealing from under a waiter? */
 int sysctl_page_lock_unfairness = 5;
 
-static struct dept_map __maybe_unused PG_locked_map = DEPT_MAP_INITIALIZER(PG_locked_map, NULL);
-static struct dept_map __maybe_unused PG_writeback_map = DEPT_MAP_INITIALIZER(PG_writeback_map, NULL);
+struct dept_map __maybe_unused PG_locked_map = DEPT_MAP_INITIALIZER(PG_locked_map, NULL);
+struct dept_map __maybe_unused PG_writeback_map = DEPT_MAP_INITIALIZER(PG_writeback_map, NULL);
 
 static inline int folio_wait_bit_common(struct folio *folio, int bit_nr,
 		int state, enum behavior behavior)
@@ -1230,6 +1232,7 @@  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)
 		sdt_might_sleep_start(&PG_locked_map);
 	else if (bit_nr == PG_writeback)
@@ -1327,6 +1330,7 @@  static inline int folio_wait_bit_common(struct folio *folio, int bit_nr,
 		wait->flags |= WQ_FLAG_DONE;
 		break;
 	}
+	dept_page_set_bit(&folio->page, bit_nr);
 
 	/*
 	 * If a signal happened, this 'finish_wait()' may remove the last
@@ -1534,6 +1538,7 @@  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 (clear_bit_unlock_is_negative_byte(PG_locked, folio_flags(folio, 0)))
 		folio_wake_bit(folio, PG_locked);
 }
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 0745aed..57d6c82 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -76,6 +76,7 @@ 
 #include <linux/khugepaged.h>
 #include <linux/buffer_head.h>
 #include <linux/delayacct.h>
+#include <linux/dept.h>
 #include <asm/sections.h>
 #include <asm/tlbflush.h>
 #include <asm/div64.h>
@@ -1626,6 +1627,8 @@  static void __meminit __init_single_page(struct page *page, unsigned long pfn,
 	page_mapcount_reset(page);
 	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