From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org,
linux-rt-users <linux-rt-users@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Carsten Emde <C.Emde@osadl.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
John Kacur <jkacur@redhat.com>,
Paul Gortmaker <paul.gortmaker@windriver.com>,
Mike Galbraith <umgwanakikbuti@gmail.com>
Subject: [PATCH RT 09/20] drivers/block/zram: Replace bit spinlocks with rtmutex for -rt
Date: Tue, 12 Jul 2016 10:24:14 -0400 [thread overview]
Message-ID: <20160712142419.010265084@goodmis.org> (raw)
In-Reply-To: 20160712142405.634544943@goodmis.org
[-- Attachment #1: 0009-drivers-block-zram-Replace-bit-spinlocks-with-rtmute.patch --]
[-- Type: text/plain, Size: 6097 bytes --]
4.1.27-rt31-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Mike Galbraith <umgwanakikbuti@gmail.com>
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>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
drivers/block/zram/zram_drv.c | 30 ++++++++++++++++--------------
drivers/block/zram/zram_drv.h | 41 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 57 insertions(+), 14 deletions(-)
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 6e134f4759c0..d2782d492630 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -386,6 +386,8 @@ static struct zram_meta *zram_meta_alloc(int device_id, u64 disksize)
goto out_error;
}
+ zram_meta_init_table_locks(meta, disksize);
+
return meta;
out_error:
@@ -484,12 +486,12 @@ static int zram_decompress_page(struct zram *zram, char *mem, u32 index)
unsigned long handle;
size_t size;
- bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
+ zram_lock_table(&meta->table[index]);
handle = meta->table[index].handle;
size = zram_get_obj_size(meta, index);
if (!handle || zram_test_flag(meta, index, ZRAM_ZERO)) {
- bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+ zram_unlock_table(&meta->table[index]);
clear_page(mem);
return 0;
}
@@ -500,7 +502,7 @@ static int zram_decompress_page(struct zram *zram, char *mem, u32 index)
else
ret = zcomp_decompress(zram->comp, cmem, size, mem);
zs_unmap_object(meta->mem_pool, handle);
- bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+ zram_unlock_table(&meta->table[index]);
/* Should NEVER happen. Return bio error if it does. */
if (unlikely(ret)) {
@@ -520,14 +522,14 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
struct zram_meta *meta = zram->meta;
page = bvec->bv_page;
- bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
+ zram_lock_table(&meta->table[index]);
if (unlikely(!meta->table[index].handle) ||
zram_test_flag(meta, index, ZRAM_ZERO)) {
- bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+ zram_unlock_table(&meta->table[index]);
handle_zero_page(bvec);
return 0;
}
- bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+ zram_unlock_table(&meta->table[index]);
if (is_partial_io(bvec))
/* Use a temporary buffer to decompress the page */
@@ -622,10 +624,10 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
if (user_mem)
kunmap_atomic(user_mem);
/* Free memory associated with this sector now. */
- bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
+ zram_lock_table(&meta->table[index]);
zram_free_page(zram, index);
zram_set_flag(meta, index, ZRAM_ZERO);
- bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+ zram_unlock_table(&meta->table[index]);
atomic64_inc(&zram->stats.zero_pages);
ret = 0;
@@ -685,12 +687,12 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
* Free memory associated with this sector
* before overwriting unused sectors.
*/
- bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
+ zram_lock_table(&meta->table[index]);
zram_free_page(zram, index);
meta->table[index].handle = handle;
zram_set_obj_size(meta, index, clen);
- bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+ zram_unlock_table(&meta->table[index]);
/* Update stats */
atomic64_add(clen, &zram->stats.compr_data_size);
@@ -762,9 +764,9 @@ static void zram_bio_discard(struct zram *zram, u32 index,
}
while (n >= PAGE_SIZE) {
- bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
+ zram_lock_table(&meta->table[index]);
zram_free_page(zram, index);
- bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+ zram_unlock_table(&meta->table[index]);
atomic64_inc(&zram->stats.notify_free);
index++;
n -= PAGE_SIZE;
@@ -1007,9 +1009,9 @@ static void zram_slot_free_notify(struct block_device *bdev,
zram = bdev->bd_disk->private_data;
meta = zram->meta;
- bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
+ zram_lock_table(&meta->table[index]);
zram_free_page(zram, index);
- bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
+ zram_unlock_table(&meta->table[index]);
atomic64_inc(&zram->stats.notify_free);
}
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index 570c598f4ce9..5f1eb86a307b 100644
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -78,6 +78,9 @@ enum zram_pageflags {
struct zram_table_entry {
unsigned long handle;
unsigned long value;
+#ifdef CONFIG_PREEMPT_RT_BASE
+ spinlock_t lock;
+#endif
};
struct zram_stats {
@@ -122,4 +125,42 @@ struct zram {
u64 disksize; /* bytes */
char compressor[10];
};
+
+#ifndef CONFIG_PREEMPT_RT_BASE
+static inline void zram_lock_table(struct zram_table_entry *table)
+{
+ bit_spin_lock(ZRAM_ACCESS, &table->value);
+}
+
+static inline void zram_unlock_table(struct zram_table_entry *table)
+{
+ bit_spin_unlock(ZRAM_ACCESS, &table->value);
+}
+
+static inline void zram_meta_init_locks(struct zram_meta *meta, u64 disksize) { }
+#else /* CONFIG_PREEMPT_RT_BASE */
+static inline void zram_lock_table(struct zram_table_entry *table)
+{
+ spin_lock(&table->lock);
+ __set_bit(ZRAM_ACCESS, &table->value);
+}
+
+static inline void zram_unlock_table(struct zram_table_entry *table)
+{
+ __clear_bit(ZRAM_ACCESS, &table->value);
+ spin_unlock(&table->lock);
+}
+
+static inline void zram_meta_init_table_locks(struct zram_meta *meta, u64 disksize)
+{
+ size_t num_pages = disksize >> PAGE_SHIFT;
+ size_t index;
+
+ for (index = 0; index < num_pages; index++) {
+ spinlock_t *lock = &meta->table[index].lock;
+ spin_lock_init(lock);
+ }
+}
+#endif /* CONFIG_PREEMPT_RT_BASE */
+
#endif
--
2.8.1
next prev parent reply other threads:[~2016-07-12 14:24 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-12 14:24 [PATCH RT 00/20] Linux 4.1.27-rt31-rc1 Steven Rostedt
2016-07-12 14:24 ` [PATCH RT 01/20] ARM: at91: pm: simply call at91_pm_init Steven Rostedt
2016-07-12 14:24 ` [PATCH RT 02/20] ARM: at91: pm: find and remap the pmc Steven Rostedt
2016-07-12 14:24 ` [PATCH RT 03/20] ARM: at91: pm: move idle functions to pm.c Steven Rostedt
2016-07-12 14:24 ` [PATCH RT 04/20] ARM: at91: remove useless includes and function prototypes Steven Rostedt
2016-07-12 14:24 ` [PATCH RT 05/20] usb: gadget: atmel: access the PMC using regmap Steven Rostedt
2016-07-12 14:24 ` [PATCH RT 06/20] kvm, rt: change async pagefault code locking for PREEMPT_RT Steven Rostedt
2016-07-12 14:24 ` [PATCH RT 07/20] mm/zsmalloc: Use get/put_cpu_light in zs_map_object()/zs_unmap_object() Steven Rostedt
2016-07-12 14:24 ` [PATCH RT 08/20] net: dev: always take qdiscs busylock in __dev_xmit_skb() Steven Rostedt
2016-07-12 14:24 ` Steven Rostedt [this message]
2016-07-12 14:24 ` [PATCH RT 10/20] list_bl: fixup bogus lockdep warning Steven Rostedt
2016-07-12 14:24 ` [PATCH RT 11/20] ARM: imx: always use TWD on IMX6Q Steven Rostedt
2016-07-12 20:04 ` Sebastian Andrzej Siewior
2016-07-12 20:25 ` Steven Rostedt
2016-07-18 17:18 ` Grygorii Strashko
2016-07-12 14:24 ` [PATCH RT 12/20] drivers/block/zram: fixup compile for !RT Steven Rostedt
2016-07-12 14:24 ` [PATCH RT 13/20] perf/x86/intel/rapl: Make PMU lock raw Steven Rostedt
2016-07-12 14:24 ` [PATCH RT 14/20] sched,preempt: Fix preempt_count manipulations Steven Rostedt
2016-07-12 14:24 ` [PATCH RT 15/20] kernel/printk: Dont try to print from IRQ/NMI region Steven Rostedt
2016-07-12 14:24 ` [PATCH RT 16/20] arm: lazy preempt: correct resched condition Steven Rostedt
2016-07-12 14:24 ` [PATCH RT 17/20] locallock: add local_lock_on() Steven Rostedt
2016-07-12 14:24 ` [PATCH RT 18/20] mm: perform lru_add_drain_all() remotely Steven Rostedt
2016-07-12 14:24 ` [PATCH RT 19/20] trace: correct off by one while recording the trace-event Steven Rostedt
2016-07-12 14:24 ` [PATCH RT 20/20] Linux 4.1.27-rt31-rc1 Steven Rostedt
2016-07-12 23:18 ` Linux 4.1.27-rt31-rc2 Steven Rostedt
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