100 lines
2.9 KiB
Diff
100 lines
2.9 KiB
Diff
From 5881f1272a6bf4dc4c7553942f95fa850416700c Mon Sep 17 00:00:00 2001
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From: Mike Galbraith <umgwanakikbuti@gmail.com>
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Date: Thu, 31 Mar 2016 04:08:28 +0200
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Subject: [PATCH 17/62] zram: Replace bit spinlocks with spinlock_t for
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PREEMPT_RT.
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The bit spinlock disables preemption on PREEMPT_RT. With disabled preemption it
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is not allowed to acquire other sleeping locks which includes invoking
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zs_free().
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Use a spinlock_t on PREEMPT_RT for locking and set/ clear ZRAM_LOCK after the
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lock has been acquired/ dropped.
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Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com>
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Link: https://lkml.kernel.org/r/YqIbMuHCPiQk+Ac2@linutronix.de
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---
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drivers/block/zram/zram_drv.c | 36 +++++++++++++++++++++++++++++++++++
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drivers/block/zram/zram_drv.h | 3 +++
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2 files changed, 39 insertions(+)
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diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
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index 966aab902d19..ee69e4443691 100644
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--- a/drivers/block/zram/zram_drv.c
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+++ b/drivers/block/zram/zram_drv.c
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@@ -57,6 +57,40 @@ static void zram_free_page(struct zram *zram, size_t index);
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static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
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u32 index, int offset, struct bio *bio);
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+#ifdef CONFIG_PREEMPT_RT
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+static void zram_meta_init_table_locks(struct zram *zram, size_t num_pages)
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+{
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+ size_t index;
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+
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+ for (index = 0; index < num_pages; index++)
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+ spin_lock_init(&zram->table[index].lock);
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+}
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+
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+static int zram_slot_trylock(struct zram *zram, u32 index)
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+{
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+ int ret;
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+
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+ ret = spin_trylock(&zram->table[index].lock);
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+ if (ret)
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+ __set_bit(ZRAM_LOCK, &zram->table[index].flags);
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+ return ret;
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+}
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+
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+static void zram_slot_lock(struct zram *zram, u32 index)
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+{
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+ spin_lock(&zram->table[index].lock);
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+ __set_bit(ZRAM_LOCK, &zram->table[index].flags);
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+}
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+
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+static void zram_slot_unlock(struct zram *zram, u32 index)
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+{
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+ __clear_bit(ZRAM_LOCK, &zram->table[index].flags);
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+ spin_unlock(&zram->table[index].lock);
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+}
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+
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+#else
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+
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+static void zram_meta_init_table_locks(struct zram *zram, size_t num_pages) { }
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static int zram_slot_trylock(struct zram *zram, u32 index)
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{
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@@ -72,6 +106,7 @@ static void zram_slot_unlock(struct zram *zram, u32 index)
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{
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bit_spin_unlock(ZRAM_LOCK, &zram->table[index].flags);
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}
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+#endif
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static inline bool init_done(struct zram *zram)
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{
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@@ -1187,6 +1222,7 @@ static bool zram_meta_alloc(struct zram *zram, u64 disksize)
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if (!huge_class_size)
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huge_class_size = zs_huge_class_size(zram->mem_pool);
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+ zram_meta_init_table_locks(zram, num_pages);
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return true;
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}
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diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
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index a2bda53020fd..ae7950b26db5 100644
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--- a/drivers/block/zram/zram_drv.h
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+++ b/drivers/block/zram/zram_drv.h
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@@ -62,6 +62,9 @@ struct zram_table_entry {
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unsigned long element;
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};
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unsigned long flags;
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+#ifdef CONFIG_PREEMPT_RT
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+ spinlock_t lock;
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+#endif
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#ifdef CONFIG_ZRAM_MEMORY_TRACKING
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ktime_t ac_time;
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#endif
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--
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2.43.0
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