105 lines
3.0 KiB
Diff
105 lines
3.0 KiB
Diff
From 596390e9ca896b8f80a6c5736f3e0fb63c26ca57 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 251/266] drivers/block/zram: Replace bit spinlocks with
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rtmutex for -rt
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.31-rt18.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 | 38 +++++++++++++++++++++++++++++++++++
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drivers/block/zram/zram_drv.h | 3 +++
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2 files changed, 41 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 a65505db09e5..f35eccc43558 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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@@ -53,6 +53,40 @@ 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 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].value);
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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].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 int zram_slot_trylock(struct zram *zram, u32 index)
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{
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return bit_spin_trylock(ZRAM_LOCK, &zram->table[index].value);
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@@ -67,6 +101,7 @@ 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].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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@@ -900,6 +935,8 @@ 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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@@ -930,6 +967,7 @@ 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 d1095dfdffa8..144e91061df8 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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@@ -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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--
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2.20.1
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