diff options
Diffstat (limited to 'features/rt/drivers-block-zram-Replace-bit-spinlocks-with-rtmute.patch')
| -rw-r--r-- | features/rt/drivers-block-zram-Replace-bit-spinlocks-with-rtmute.patch | 92 |
1 files changed, 92 insertions, 0 deletions
diff --git a/features/rt/drivers-block-zram-Replace-bit-spinlocks-with-rtmute.patch b/features/rt/drivers-block-zram-Replace-bit-spinlocks-with-rtmute.patch new file mode 100644 index 00000000..4ed6aa46 --- /dev/null +++ b/features/rt/drivers-block-zram-Replace-bit-spinlocks-with-rtmute.patch @@ -0,0 +1,92 @@ +From 66e6d402c94d47b29c4a7f3f5872fee8d2be6ebb Mon Sep 17 00:00:00 2001 +From: Mike Galbraith <umgwanakikbuti@gmail.com> +Date: Thu, 31 Mar 2016 04:08:28 +0200 +Subject: [PATCH 186/191] drivers/block/zram: Replace bit spinlocks with + rtmutex for -rt + +They're nondeterministic, and lead to ___might_sleep() splats in -rt. +OTOH, they're a lot less wasteful than an rtmutex per page. + +Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com> +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + drivers/block/zram/zram_drv.c | 36 +++++++++++++++++++++++++++++++++++ + drivers/block/zram/zram_drv.h | 1 + + 2 files changed, 37 insertions(+) + +diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c +index cf8deecc39ef..5c7999ebc4e0 100644 +--- a/drivers/block/zram/zram_drv.c ++++ b/drivers/block/zram/zram_drv.c +@@ -59,6 +59,40 @@ static void zram_free_page(struct zram *zram, size_t index); + static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec, + u32 index, int offset, struct bio *bio); + ++#ifdef CONFIG_PREEMPT_RT ++static void zram_meta_init_table_locks(struct zram *zram, size_t num_pages) ++{ ++ size_t index; ++ ++ for (index = 0; index < num_pages; index++) ++ spin_lock_init(&zram->table[index].lock); ++} ++ ++static int zram_slot_trylock(struct zram *zram, u32 index) ++{ ++ int ret; ++ ++ ret = spin_trylock(&zram->table[index].lock); ++ if (ret) ++ __set_bit(ZRAM_LOCK, &zram->table[index].flags); ++ return ret; ++} ++ ++static void zram_slot_lock(struct zram *zram, u32 index) ++{ ++ spin_lock(&zram->table[index].lock); ++ __set_bit(ZRAM_LOCK, &zram->table[index].flags); ++} ++ ++static void zram_slot_unlock(struct zram *zram, u32 index) ++{ ++ __clear_bit(ZRAM_LOCK, &zram->table[index].flags); ++ spin_unlock(&zram->table[index].lock); ++} ++ ++#else ++ ++static void zram_meta_init_table_locks(struct zram *zram, size_t num_pages) { } + + static int zram_slot_trylock(struct zram *zram, u32 index) + { +@@ -74,6 +108,7 @@ static void zram_slot_unlock(struct zram *zram, u32 index) + { + bit_spin_unlock(ZRAM_LOCK, &zram->table[index].flags); + } ++#endif + + static inline bool init_done(struct zram *zram) + { +@@ -1169,6 +1204,7 @@ static bool zram_meta_alloc(struct zram *zram, u64 disksize) + + if (!huge_class_size) + huge_class_size = zs_huge_class_size(zram->mem_pool); ++ zram_meta_init_table_locks(zram, num_pages); + return true; + } + +diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h +index 419a7e8281ee..561c7ba1421f 100644 +--- a/drivers/block/zram/zram_drv.h ++++ b/drivers/block/zram/zram_drv.h +@@ -63,6 +63,7 @@ struct zram_table_entry { + unsigned long element; + }; + unsigned long flags; ++ spinlock_t lock; + #ifdef CONFIG_ZRAM_MEMORY_TRACKING + ktime_t ac_time; + #endif +-- +2.19.1 + |