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85 lines
2.3 KiB
Diff
85 lines
2.3 KiB
Diff
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] drivers/block/zram: Replace bit spinlocks with rtmutex
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for -rt
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They're nondeterministic, and lead to ___might_sleep() splats in -rt.
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OTOH, they're a lot less wasteful than an rtmutex per page.
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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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---
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drivers/block/zram/zram_drv.c | 36 ++++++++++++++++++++++++++++++++++++
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drivers/block/zram/zram_drv.h | 1 +
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2 files changed, 37 insertions(+)
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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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@@ -59,6 +59,40 @@ static void zram_free_page(struct zram *
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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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@@ -74,6 +108,7 @@ static void zram_slot_unlock(struct zram
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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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@@ -1165,6 +1200,7 @@ static bool zram_meta_alloc(struct zram
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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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--- a/drivers/block/zram/zram_drv.h
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+++ b/drivers/block/zram/zram_drv.h
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@@ -63,6 +63,7 @@ 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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+ spinlock_t lock;
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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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