Messages in this thread Patch in this message | | | From | qiang.zhang@windrive ... | Subject | [PATCH v2] kvfree_rcu: Release page cache under memory pressure | Date | Fri, 29 Jan 2021 16:04:42 +0800 |
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From: Zqiang <qiang.zhang@windriver.com>
Add free per-cpu existing krcp's page cache operation, when the system is under memory pressure.
Signed-off-by: Zqiang <qiang.zhang@windriver.com> --- kernel/rcu/tree.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index c1ae1e52f638..ec098910d80b 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -3571,17 +3571,40 @@ void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func) } EXPORT_SYMBOL_GPL(kvfree_call_rcu); +static int free_krc_page_cache(struct kfree_rcu_cpu *krcp) +{ + unsigned long flags; + struct kvfree_rcu_bulk_data *bnode; + int i; + + for (i = 0; i < rcu_min_cached_objs; i++) { + raw_spin_lock_irqsave(&krcp->lock, flags); + bnode = get_cached_bnode(krcp); + raw_spin_unlock_irqrestore(&krcp->lock, flags); + if (!bnode) + break; + free_page((unsigned long)bnode); + } + + return i; +} + static unsigned long kfree_rcu_shrink_count(struct shrinker *shrink, struct shrink_control *sc) { int cpu; unsigned long count = 0; + unsigned long flags; /* Snapshot count of all CPUs */ for_each_possible_cpu(cpu) { struct kfree_rcu_cpu *krcp = per_cpu_ptr(&krc, cpu); count += READ_ONCE(krcp->count); + + raw_spin_lock_irqsave(&krcp->lock, flags); + count += krcp->nr_bkv_objs; + raw_spin_unlock_irqrestore(&krcp->lock, flags); } return count; @@ -3598,6 +3621,8 @@ kfree_rcu_shrink_scan(struct shrinker *shrink, struct shrink_control *sc) struct kfree_rcu_cpu *krcp = per_cpu_ptr(&krc, cpu); count = krcp->count; + count += free_krc_page_cache(krcp); + raw_spin_lock_irqsave(&krcp->lock, flags); if (krcp->monitor_todo) kfree_rcu_drain_unlock(krcp, flags); -- 2.17.1
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