The patch titled
Subject: mm/mmu_notifier: allocate mmu_notifier in advance
has been removed from the -mm tree. Its filename was
mm-mmu_notifier-allocate-mmu_notifier-in-advance.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Gavin Shan <shangw@xxxxxxxxxxxxxxxxxx>
Subject: mm/mmu_notifier: allocate mmu_notifier in advance
While allocating mmu_notifier with parameter GFP_KERNEL, swap would start
to work in case of tight available memory. Eventually, that would lead to
a deadlock while the swap deamon swaps anonymous pages. It was caused by
commit e0f3c3f78da29b ("mm/mmu_notifier: init notifier if necessary").
: [49048.262912] =================================
: [49048.262913] [ INFO: inconsistent lock state ]
: [49048.262916] 3.7.0-rc1+ #518 Not tainted
: [49048.262918] ---------------------------------
: [49048.262919] inconsistent {RECLAIM_FS-ON-W} -> {IN-RECLAIM_FS-W} usage.
: [49048.262922] kswapd0/35 [HC0[0]:SC0[0]:HE1:SE1] takes:
: [49048.262924] (&mapping->i_mmap_mutex){+.+.?.}, at: [<ffffffff81192fbc>] page_referenced+0x9c/0x2e0
: [49048.262933] {RECLAIM_FS-ON-W} state was registered at:
: [49048.262935] [<ffffffff810ed5d6>] mark_held_locks+0x86/0x150
: [49048.262938] [<ffffffff810edce7>] lockdep_trace_alloc+0x67/0xc0
: [49048.262942] [<ffffffff811a9323>] kmem_cache_alloc_trace+0x33/0x230
: [49048.262945] [<ffffffff811a1a27>] do_mmu_notifier_register+0x87/0x180
: [49048.262948] [<ffffffff811a1b53>] mmu_notifier_register+0x13/0x20
: [49048.262951] [<ffffffff81006738>] kvm_dev_ioctl+0x428/0x510
: [49048.262955] [<ffffffff811c7ce8>] do_vfs_ioctl+0x98/0x570
: [49048.262959] [<ffffffff811c8251>] sys_ioctl+0x91/0xb0
: [49048.262962] [<ffffffff815df302>] system_call_fastpath+0x16/0x1b
: [49048.262966] irq event stamp: 825
: [49048.262968] hardirqs last enabled at (825): [<ffffffff815d6fa0>] _raw_spin_unlock_irq+0x30/0x60
: [49048.262971] hardirqs last disabled at (824): [<ffffffff815d6659>] _raw_spin_lock_irq+0x19/0x80
: [49048.262975] softirqs last enabled at (0): [<ffffffff81082170>] copy_process+0x630/0x17c0
: [49048.262979] softirqs last disabled at (0): [< (null)>] (null)
: ...
Simply back out the above commit, which was a small performance
optimization.
Signed-off-by: Gavin Shan <shangw@xxxxxxxxxxxxxxxxxx>
Reported-by: Andrea Righi <andrea@xxxxxxxxxxxxxxx>
Tested-by: Andrea Righi <andrea@xxxxxxxxxxxxxxx>
Cc: Wanpeng Li <liwanp@xxxxxxxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Avi Kivity <avi@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
Cc: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxxxxxx>
Cc: Sagi Grimberg <sagig@xxxxxxxxxxxxxx>
Cc: Haggai Eran <haggaie@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mmu_notifier.c | 26 +++++++++++++-------------
1 file changed, 13 insertions(+), 13 deletions(-)
diff -puN mm/mmu_notifier.c~mm-mmu_notifier-allocate-mmu_notifier-in-advance mm/mmu_notifier.c
--- a/mm/mmu_notifier.c~mm-mmu_notifier-allocate-mmu_notifier-in-advance
+++ a/mm/mmu_notifier.c
@@ -196,28 +196,28 @@ static int do_mmu_notifier_register(stru
BUG_ON(atomic_read(&mm->mm_users) <= 0);
/*
- * Verify that mmu_notifier_init() already run and the global srcu is
- * initialized.
- */
+ * Verify that mmu_notifier_init() already run and the global srcu is
+ * initialized.
+ */
BUG_ON(!srcu.per_cpu_ref);
+ ret = -ENOMEM;
+ mmu_notifier_mm = kmalloc(sizeof(struct mmu_notifier_mm), GFP_KERNEL);
+ if (unlikely(!mmu_notifier_mm))
+ goto out;
+
if (take_mmap_sem)
down_write(&mm->mmap_sem);
ret = mm_take_all_locks(mm);
if (unlikely(ret))
- goto out;
+ goto out_clean;
if (!mm_has_notifiers(mm)) {
- mmu_notifier_mm = kmalloc(sizeof(struct mmu_notifier_mm),
- GFP_KERNEL);
- if (unlikely(!mmu_notifier_mm)) {
- ret = -ENOMEM;
- goto out_of_mem;
- }
INIT_HLIST_HEAD(&mmu_notifier_mm->list);
spin_lock_init(&mmu_notifier_mm->lock);
mm->mmu_notifier_mm = mmu_notifier_mm;
+ mmu_notifier_mm = NULL;
}
atomic_inc(&mm->mm_count);
@@ -233,12 +233,12 @@ static int do_mmu_notifier_register(stru
hlist_add_head(&mn->hlist, &mm->mmu_notifier_mm->list);
spin_unlock(&mm->mmu_notifier_mm->lock);
-out_of_mem:
mm_drop_all_locks(mm);
-out:
+out_clean:
if (take_mmap_sem)
up_write(&mm->mmap_sem);
-
+ kfree(mmu_notifier_mm);
+out:
BUG_ON(atomic_read(&mm->mm_users) <= 0);
return ret;
}
_
Patches currently in -mm which might be from shangw@xxxxxxxxxxxxxxxxxx are
mm-slab-remove-duplicate-check.patch
mm-memblock-reduce-overhead-in-binary-search.patch
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