87 lines
2.5 KiB
Diff
87 lines
2.5 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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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.1-rt3.tar.xz
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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 | 28 ++++++++++++++++++++++++++++
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drivers/block/zram/zram_drv.h | 3 +++
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2 files changed, 31 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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@@ -53,6 +53,30 @@ static size_t huge_class_size;
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static void zram_free_page(struct zram *zram, size_t index);
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+#ifdef CONFIG_PREEMPT_RT_BASE
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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 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].value);
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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].value);
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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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+static void zram_meta_init_table_locks(struct zram *zram, size_t num_pages) { }
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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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bit_spin_lock(ZRAM_LOCK, &zram->table[index].value);
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@@ -62,6 +86,7 @@ static void zram_slot_unlock(struct zram
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{
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bit_spin_unlock(ZRAM_LOCK, &zram->table[index].value);
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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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@@ -898,6 +923,8 @@ static DEVICE_ATTR_RO(io_stat);
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static DEVICE_ATTR_RO(mm_stat);
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static DEVICE_ATTR_RO(debug_stat);
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+
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+
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static void zram_meta_free(struct zram *zram, u64 disksize)
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{
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size_t num_pages = disksize >> PAGE_SHIFT;
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@@ -928,6 +955,7 @@ 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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@@ -61,6 +61,9 @@ struct zram_table_entry {
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unsigned long element;
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};
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unsigned long value;
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+#ifdef CONFIG_PREEMPT_RT_BASE
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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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