From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: mm: report a more useful address for reclaim acquisition
A recent lockdep report included these lines:
[ 96.177910] 3 locks held by containerd/770:
[ 96.177934] #0: ffff88810815ea28 (&mm->mmap_lock#2){++++}-{3:3},
at: do_user_addr_fault+0x115/0x770
[ 96.177999] #1: ffffffff82915020 (rcu_read_lock){....}-{1:2}, at:
get_swap_device+0x33/0x140
[ 96.178057] #2: ffffffff82955ba0 (fs_reclaim){+.+.}-{0:0}, at:
__fs_reclaim_acquire+0x5/0x30
While it was not useful to that bug report to know where the reclaim lock
had been acquired, it might be useful under other circumstances. Allow
the caller of __fs_reclaim_acquire to specify the instruction pointer to
use.
Link: https://lkml.kernel.org/r/20210719185709.1755149-1-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Omar Sandoval <osandov@xxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Boqun Feng <boqun.feng@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/sched/mm.h | 8 ++++----
mm/page_alloc.c | 12 ++++++------
mm/vmscan.c | 8 ++++----
3 files changed, 14 insertions(+), 14 deletions(-)
--- a/include/linux/sched/mm.h~mm-report-a-more-useful-address-for-reclaim-acquisition
+++ a/include/linux/sched/mm.h
@@ -174,13 +174,13 @@ static inline gfp_t current_gfp_context(
}
#ifdef CONFIG_LOCKDEP
-extern void __fs_reclaim_acquire(void);
-extern void __fs_reclaim_release(void);
+extern void __fs_reclaim_acquire(unsigned long ip);
+extern void __fs_reclaim_release(unsigned long ip);
extern void fs_reclaim_acquire(gfp_t gfp_mask);
extern void fs_reclaim_release(gfp_t gfp_mask);
#else
-static inline void __fs_reclaim_acquire(void) { }
-static inline void __fs_reclaim_release(void) { }
+static inline void __fs_reclaim_acquire(unsigned long ip) { }
+static inline void __fs_reclaim_release(unsigned long ip) { }
static inline void fs_reclaim_acquire(gfp_t gfp_mask) { }
static inline void fs_reclaim_release(gfp_t gfp_mask) { }
#endif
--- a/mm/page_alloc.c~mm-report-a-more-useful-address-for-reclaim-acquisition
+++ a/mm/page_alloc.c
@@ -4549,14 +4549,14 @@ static bool __need_reclaim(gfp_t gfp_mas
return true;
}
-void __fs_reclaim_acquire(void)
+void __fs_reclaim_acquire(unsigned long ip)
{
- lock_map_acquire(&__fs_reclaim_map);
+ lock_acquire_exclusive(&__fs_reclaim_map, 0, 0, NULL, ip);
}
-void __fs_reclaim_release(void)
+void __fs_reclaim_release(unsigned long ip)
{
- lock_map_release(&__fs_reclaim_map);
+ lock_release(&__fs_reclaim_map, ip);
}
void fs_reclaim_acquire(gfp_t gfp_mask)
@@ -4565,7 +4565,7 @@ void fs_reclaim_acquire(gfp_t gfp_mask)
if (__need_reclaim(gfp_mask)) {
if (gfp_mask & __GFP_FS)
- __fs_reclaim_acquire();
+ __fs_reclaim_acquire(_RET_IP_);
#ifdef CONFIG_MMU_NOTIFIER
lock_map_acquire(&__mmu_notifier_invalidate_range_start_map);
@@ -4582,7 +4582,7 @@ void fs_reclaim_release(gfp_t gfp_mask)
if (__need_reclaim(gfp_mask)) {
if (gfp_mask & __GFP_FS)
- __fs_reclaim_release();
+ __fs_reclaim_release(_RET_IP_);
}
}
EXPORT_SYMBOL_GPL(fs_reclaim_release);
--- a/mm/vmscan.c~mm-report-a-more-useful-address-for-reclaim-acquisition
+++ a/mm/vmscan.c
@@ -3812,7 +3812,7 @@ static int balance_pgdat(pg_data_t *pgda
set_task_reclaim_state(current, &sc.reclaim_state);
psi_memstall_enter(&pflags);
- __fs_reclaim_acquire();
+ __fs_reclaim_acquire(_THIS_IP_);
count_vm_event(PAGEOUTRUN);
@@ -3938,9 +3938,9 @@ restart:
wake_up_all(&pgdat->pfmemalloc_wait);
/* Check if kswapd should be suspending */
- __fs_reclaim_release();
+ __fs_reclaim_release(_THIS_IP_);
ret = try_to_freeze();
- __fs_reclaim_acquire();
+ __fs_reclaim_acquire(_THIS_IP_);
if (ret || kthread_should_stop())
break;
@@ -3992,7 +3992,7 @@ out:
}
snapshot_refaults(NULL, pgdat);
- __fs_reclaim_release();
+ __fs_reclaim_release(_THIS_IP_);
psi_memstall_leave(&pflags);
set_task_reclaim_state(current, NULL);
_
