From: Mike Galbraith <umgwanakikbuti@gmail.com>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
linux-rt-users <linux-rt-users@vger.kernel.org>,
Steven Rostedt <rostedt@goodmis.org>
Subject: [patch v2 ] mm/zs_malloc: Fix bit spinlock replacement
Date: Wed, 19 Oct 2016 17:50:38 +0200 [thread overview]
Message-ID: <1476892238.3975.1.camel@gmail.com> (raw)
In-Reply-To: <1476587883.1538.12.camel@gmail.com>
Do not alter HANDLE_SIZE, memory corruption ensues. The handle is
a pointer, allocate space for the struct it points to and align it
ZS_ALIGN. Also, when accessing the struct, mask HANDLE_PIN_BIT.
v2: mutex is only needed for PREEMPT_RT_FULL, with PREEMPT_RT_RTB,
preemption is disabled when we take it...
Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com>
---
mm/zsmalloc.c | 31 +++++++++++++++++--------------
1 file changed, 17 insertions(+), 14 deletions(-)
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -71,18 +71,20 @@
#define ZS_MAX_ZSPAGE_ORDER 2
#define ZS_MAX_PAGES_PER_ZSPAGE (_AC(1, UL) << ZS_MAX_ZSPAGE_ORDER)
-#ifdef CONFIG_PREEMPT_RT_BASE
+#define ZS_HANDLE_SIZE (sizeof(unsigned long))
+
+#ifdef CONFIG_PREEMPT_RT_FULL
struct zsmalloc_handle {
unsigned long addr;
struct mutex lock;
};
-#define ZS_HANDLE_SIZE (sizeof(struct zsmalloc_handle))
+#define ZS_HANDLE_ALLOC_SIZE (sizeof(struct zsmalloc_handle))
#else
-#define ZS_HANDLE_SIZE (sizeof(unsigned long))
+#define ZS_HANDLE_ALLOC_SIZE ZS_HANDLE_SIZE
#endif
/*
@@ -339,8 +341,9 @@ static void SetZsPageMovable(struct zs_p
static int create_cache(struct zs_pool *pool)
{
- pool->handle_cachep = kmem_cache_create("zs_handle", ZS_HANDLE_SIZE,
- 0, 0, NULL);
+ pool->handle_cachep = kmem_cache_create("zs_handle",
+ ZS_HANDLE_ALLOC_SIZE,
+ ZS_ALIGN, 0, NULL);
if (!pool->handle_cachep)
return 1;
@@ -367,7 +370,7 @@ static unsigned long cache_alloc_handle(
p = kmem_cache_alloc(pool->handle_cachep,
gfp & ~(__GFP_HIGHMEM|__GFP_MOVABLE));
-#ifdef CONFIG_PREEMPT_RT_BASE
+#ifdef CONFIG_PREEMPT_RT_FULL
if (p) {
struct zsmalloc_handle *zh = p;
@@ -377,10 +380,10 @@ static unsigned long cache_alloc_handle(
return (unsigned long)p;
}
-#ifdef CONFIG_PREEMPT_RT_BASE
+#ifdef CONFIG_PREEMPT_RT_FULL
static struct zsmalloc_handle *zs_get_pure_handle(unsigned long handle)
{
- return (void *)(handle &~((1 << OBJ_TAG_BITS) - 1));
+ return (void *)(handle & ~BIT(HANDLE_PIN_BIT));
}
#endif
@@ -402,7 +405,7 @@ static void cache_free_zspage(struct zs_
static void record_obj(unsigned long handle, unsigned long obj)
{
-#ifdef CONFIG_PREEMPT_RT_BASE
+#ifdef CONFIG_PREEMPT_RT_FULL
struct zsmalloc_handle *zh = zs_get_pure_handle(handle);
WRITE_ONCE(zh->addr, obj);
@@ -937,7 +940,7 @@ static unsigned long location_to_obj(str
static unsigned long handle_to_obj(unsigned long handle)
{
-#ifdef CONFIG_PREEMPT_RT_BASE
+#ifdef CONFIG_PREEMPT_RT_FULL
struct zsmalloc_handle *zh = zs_get_pure_handle(handle);
return zh->addr;
@@ -957,7 +960,7 @@ static unsigned long obj_to_head(struct
static inline int testpin_tag(unsigned long handle)
{
-#ifdef CONFIG_PREEMPT_RT_BASE
+#ifdef CONFIG_PREEMPT_RT_FULL
struct zsmalloc_handle *zh = zs_get_pure_handle(handle);
return mutex_is_locked(&zh->lock);
@@ -968,7 +971,7 @@ static inline int testpin_tag(unsigned l
static inline int trypin_tag(unsigned long handle)
{
-#ifdef CONFIG_PREEMPT_RT_BASE
+#ifdef CONFIG_PREEMPT_RT_FULL
struct zsmalloc_handle *zh = zs_get_pure_handle(handle);
return mutex_trylock(&zh->lock);
@@ -979,7 +982,7 @@ static inline int trypin_tag(unsigned lo
static void pin_tag(unsigned long handle)
{
-#ifdef CONFIG_PREEMPT_RT_BASE
+#ifdef CONFIG_PREEMPT_RT_FULL
struct zsmalloc_handle *zh = zs_get_pure_handle(handle);
return mutex_lock(&zh->lock);
@@ -990,7 +993,7 @@ static void pin_tag(unsigned long handle
static void unpin_tag(unsigned long handle)
{
-#ifdef CONFIG_PREEMPT_RT_BASE
+#ifdef CONFIG_PREEMPT_RT_FULL
struct zsmalloc_handle *zh = zs_get_pure_handle(handle);
return mutex_unlock(&zh->lock);
next prev parent reply other threads:[~2016-10-19 15:50 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-06 8:52 [ANNOUNCE] 4.8-rt1 Sebastian Andrzej Siewior
2016-10-16 3:08 ` [patch] ftrace: Fix latency trace header alignment Mike Galbraith
2016-10-17 13:23 ` Sebastian Andrzej Siewior
2016-10-16 3:11 ` [patch] drivers,connector: Protect send_msg() with a local lock for RT Mike Galbraith
2016-10-17 14:16 ` Sebastian Andrzej Siewior
2016-10-16 3:14 ` [patch] drivers/zram: Don't disable preemption in zcomp_stream_get/put() Mike Galbraith
2016-10-17 14:24 ` Sebastian Andrzej Siewior
2016-10-17 16:19 ` Mike Galbraith
2016-10-17 16:29 ` Sebastian Andrzej Siewior
2016-10-17 17:18 ` Mike Galbraith
2016-10-17 17:46 ` Mike Galbraith
2016-10-19 15:56 ` [patch v2] " Mike Galbraith
2016-10-19 16:54 ` Sebastian Andrzej Siewior
2016-10-20 2:59 ` Mike Galbraith
2016-10-20 11:02 ` Sebastian Andrzej Siewior
2016-10-16 3:18 ` [patch ]mm/zs_malloc: Fix bit spinlock replacement Mike Galbraith
2016-10-17 15:15 ` Sebastian Andrzej Siewior
2016-10-17 16:12 ` Mike Galbraith
2016-10-19 15:50 ` Mike Galbraith [this message]
2016-10-20 10:59 ` [patch v2 ] mm/zs_malloc: " Sebastian Andrzej Siewior
2016-10-20 9:34 ` [rfc patch] hotplug: Call mmdrop_delayed() in sched_cpu_dying() if PREEMPT_RT_FULL Mike Galbraith
2016-10-20 11:21 ` Sebastian Andrzej Siewior
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