lkml.org 
[lkml]   [2001]   [Sep]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patches in this message
/
Date
From
SubjectRe: [PATCH] Align VM locks, new spinlock patch
Andrea Arcangeli wrote:

> On Thu, Aug 16, 2001 at 12:14:23PM -0700, Andrew Morton wrote:
> > Problem with this approach is that it doesn't prevent the linker
> > from placing other data in the same cacheline as the aligned
> > lock, at higher addresses.
>
> that was partly intentional, but ok we can be more aggressive on that
> side ;).
>
> > Juergen, I'd suggest you dust off that patch, add the conditionals
> > which make it a no-op on uniprocessor and submit it. It's such a
>
> agreed, btw it is just a noop on up but it is undefined for __GNUC__ >
> 2, also it would be nice if he could do it in linux/ instead of asm/, it
> should not need special arch trick (spinlock_t and SMP_CACHE_SIZE are
> the only thing it needs).


Sorry, it tooks some time, because of my vacation and then the disk drive
I used for testing gets damaged.

I changed the spinlock patch according to your suggestions.

Description
-----------

The patch introduces a new type spinlock_cacheline_t which
o aligns the spinlock to a cacheline and
o avoids that this spinlock shares the cacheline with other data
This type is now hardware independent.

It declares following spinlocks from type spinlock_cacheline_t:
o kmap_lock
o pagecache_lock
o pagemap_lru_lock
o lru_list_lock
o kernel_flag
Where the kernel_flag is modified only for i386 architecture, because
the spinlock itself is hardware dependent implemented.

I tested the patch on 2.4.5, 2.4.8, and 2.4.10-pre7.
Kernel 2.4.10-pre7 requires a separate version of the patch, because
the pagecache_lock and the lru_list_lock are already aligned.


The peak throughput results with dbench:

2.4.10 2.4.10 + improvement
spinlock patch by patch

U 103.77 102.14 - 1.6%
1 96.82 96.77 - 0.1%
2 155.32 155.62 0.2%
4 209.45 222.11 6.0%
8 208.06 234.82 12.9%

The improvement is less than in previous posted results, because the
pagemap_lru_lock and the lru_list_lock are already cacheline aligned
in 2.4.10 (2.4.9).

I attached two versions of the patch, one which applies for 2.4.x-2.4.8
and below a version for 2.4.10 (heading: Spinlock patch for kernel 2.4.10),
which applies also to 2.4.9, but I didn't test it.

Juergen

______________________________________________________________
Juergen Doelle
IBM Linux Technology Center - kernel performance
jdoelle@de.ibm.com




= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Spinlock patch for kernel 2.4.x-2.4.8
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

--- linux/include/asm-i386/smplock.h.orig Thu Sep 6 14:46:25 2001
+++ linux/include/asm-i386/smplock.h Thu Sep 6 16:38:02 2001
@@ -8,7 +8,13 @@
#include <linux/sched.h>
#include <asm/current.h>

-extern spinlock_t kernel_flag;
+
+#ifdef CONFIG_SMP
+ extern spinlock_cacheline_t kernel_flag_cacheline;
+ #define kernel_flag kernel_flag_cacheline.lock
+#else
+ extern spinlock_t kernel_flag;
+#endif

#define kernel_locked() spin_is_locked(&kernel_flag)

--- linux/arch/i386/kernel/i386_ksyms.c.orig Thu Sep 6 16:00:29 2001
+++ linux/arch/i386/kernel/i386_ksyms.c Thu Sep 6 16:03:07 2001
@@ -120,7 +120,7 @@

#ifdef CONFIG_SMP
EXPORT_SYMBOL(cpu_data);
-EXPORT_SYMBOL(kernel_flag);
+EXPORT_SYMBOL(kernel_flag_cacheline);
EXPORT_SYMBOL(smp_num_cpus);
EXPORT_SYMBOL(cpu_online_map);
EXPORT_SYMBOL_NOVERS(__write_lock_failed);
--- linux/include/linux/spinlock.h.orig Thu Sep 6 14:30:41 2001
+++ linux/include/linux/spinlock.h Thu Sep 6 16:38:02 2001
@@ -34,6 +34,13 @@
#ifdef CONFIG_SMP
#include <asm/spinlock.h>

+#include <linux/cache.h>
+typedef union {
+ spinlock_t lock;
+ char fill_up[(SMP_CACHE_BYTES)];
+} spinlock_cacheline_t __attribute__ ((aligned(SMP_CACHE_BYTES)));
+
+
#elif !defined(spin_lock_init) /* !SMP and spin_lock_init not previously
defined (e.g. by including asm/spinlock.h */

--- linux/include/linux/swap.h.orig Thu Sep 6 14:38:01 2001
+++ linux/include/linux/swap.h Thu Sep 6 16:38:02 2001
@@ -88,7 +88,13 @@
extern struct address_space swapper_space;
extern atomic_t page_cache_size;
extern atomic_t buffermem_pages;
-extern spinlock_t pagecache_lock;
+#ifdef CONFIG_SMP
+ extern spinlock_cacheline_t pagecache_lock_cacheline;
+ #define pagecache_lock (pagecache_lock_cacheline.lock)
+#else
+ extern spinlock_t pagecache_lock;
+#endif
+
extern void __remove_inode_page(struct page *);

/* Incomplete types for prototype declarations: */
@@ -179,7 +185,12 @@
extern unsigned long swap_cache_find_success;
#endif

-extern spinlock_t pagemap_lru_lock;
+#ifdef CONFIG_SMP
+ extern spinlock_cacheline_t pagemap_lru_lock_cacheline;
+ #define pagemap_lru_lock pagemap_lru_lock_cacheline.lock
+#else
+ extern spinlock_t pagemap_lru_lock;
+#endif

/*
* Page aging defines.
--- linux/fs/buffer.c.orig Thu Sep 6 15:10:07 2001
+++ linux/fs/buffer.c Thu Sep 6 15:54:00 2001
@@ -83,13 +83,22 @@
static rwlock_t hash_table_lock = RW_LOCK_UNLOCKED;

static struct buffer_head *lru_list[NR_LIST];
-static spinlock_t lru_list_lock = SPIN_LOCK_UNLOCKED;
+
+#ifdef CONFIG_SMP
+ static spinlock_cacheline_t lru_list_lock_cacheline = {SPIN_LOCK_UNLOCKED};
+ #ifndef lru_list_lock
+ #define lru_list_lock lru_list_lock_cacheline.lock
+ #endif
+#else
+ static spinlock_t lru_list_lock = SPIN_LOCK_UNLOCKED;
+#endif
static int nr_buffers_type[NR_LIST];
static unsigned long size_buffers_type[NR_LIST];

static struct buffer_head * unused_list;
static int nr_unused_buffer_heads;
static spinlock_t unused_list_lock = SPIN_LOCK_UNLOCKED;
+
static DECLARE_WAIT_QUEUE_HEAD(buffer_wait);

struct bh_free_head {
--- linux/mm/filemap.c.orig Thu Sep 6 14:55:44 2001
+++ linux/mm/filemap.c Thu Sep 6 15:06:21 2001
@@ -45,12 +45,28 @@
unsigned int page_hash_bits;
struct page **page_hash_table;

-spinlock_t pagecache_lock = SPIN_LOCK_UNLOCKED;
+#ifdef CONFIG_SMP
+ spinlock_cacheline_t pagecache_lock_cacheline = {SPIN_LOCK_UNLOCKED};
+ #ifndef pagecache_lock
+ #define pagecache_lock pagecache_lock_cacheline.lock
+ #endif
+#else
+ spinlock_t pagecache_lock = SPIN_LOCK_UNLOCKED;
+#endif
+
/*
* NOTE: to avoid deadlocking you must never acquire the pagecache_lock with
* the pagemap_lru_lock held.
*/
-spinlock_t pagemap_lru_lock = SPIN_LOCK_UNLOCKED;
+#ifdef CONFIG_SMP
+ spinlock_cacheline_t pagemap_lru_lock_cacheline = {SPIN_LOCK_UNLOCKED};
+ #ifndef pagemap_lru_lock
+ #define pagemap_lru_lock pagemap_lru_lock_cacheline.lock
+ #endif
+#else
+ spinlock_t pagemap_lru_lock = SPIN_LOCK_UNLOCKED;
+#endif
+

#define CLUSTER_PAGES (1 << page_cluster)
#define CLUSTER_OFFSET(x) (((x) >> page_cluster) << page_cluster)
--- linux/mm/highmem.c.orig Thu Sep 6 14:55:54 2001
+++ linux/mm/highmem.c Thu Sep 6 15:08:22 2001
@@ -32,7 +32,14 @@
*/
static int pkmap_count[LAST_PKMAP];
static unsigned int last_pkmap_nr;
-static spinlock_t kmap_lock = SPIN_LOCK_UNLOCKED;
+#ifdef CONFIG_SMP
+ static spinlock_cacheline_t kmap_lock_cacheline = {SPIN_LOCK_UNLOCKED};
+ #ifndef kmap_lock
+ #define kmap_lock kmap_lock_cacheline.lock
+ #endif
+#else
+ static spinlock_t kmap_lock = SPIN_LOCK_UNLOCKED;
+#endif

pte_t * pkmap_page_table;

--- linux/arch/i386/kernel/smp.c.orig Thu Sep 6 14:52:01 2001
+++ linux/arch/i386/kernel/smp.c Thu Sep 6 16:04:38 2001
@@ -101,7 +101,14 @@
*/

/* The 'big kernel lock' */
+#ifdef CONFIG_SMP
+ spinlock_cacheline_t kernel_flag_cacheline = {SPIN_LOCK_UNLOCKED};
+ #ifndef kernel_flag
+ #define kernel_flag kernel_flag_cacheline.lock
+ #endif
+#else
spinlock_t kernel_flag = SPIN_LOCK_UNLOCKED;
+#endif

struct tlb_state cpu_tlbstate[NR_CPUS] = {[0 ... NR_CPUS-1] = { &init_mm, 0 }};

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
Spinlock patch for kernel 2.4.10 (2.4.9)
= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

--- linux/include/asm-i386/smplock.h.orig Thu Sep 6 14:46:25 2001
+++ linux/include/asm-i386/smplock.h Thu Sep 6 16:38:02 2001
@@ -8,7 +8,13 @@
#include <linux/sched.h>
#include <asm/current.h>

-extern spinlock_t kernel_flag;
+
+#ifdef CONFIG_SMP
+ extern spinlock_cacheline_t kernel_flag_cacheline;
+ #define kernel_flag kernel_flag_cacheline.lock
+#else
+ extern spinlock_t kernel_flag;
+#endif

#define kernel_locked() spin_is_locked(&kernel_flag)

--- linux/arch/i386/kernel/i386_ksyms.c.orig Thu Sep 6 16:00:29 2001
+++ linux/arch/i386/kernel/i386_ksyms.c Thu Sep 6 16:03:07 2001
@@ -120,7 +120,7 @@

#ifdef CONFIG_SMP
EXPORT_SYMBOL(cpu_data);
-EXPORT_SYMBOL(kernel_flag);
+EXPORT_SYMBOL(kernel_flag_cacheline);
EXPORT_SYMBOL(smp_num_cpus);
EXPORT_SYMBOL(cpu_online_map);
EXPORT_SYMBOL_NOVERS(__write_lock_failed);
--- linux/include/linux/spinlock.h.orig Thu Sep 6 14:30:41 2001
+++ linux/include/linux/spinlock.h Thu Sep 6 16:38:02 2001
@@ -34,6 +34,13 @@
#ifdef CONFIG_SMP
#include <asm/spinlock.h>

+#include <linux/cache.h>
+typedef union {
+ spinlock_t lock;
+ char fill_up[(SMP_CACHE_BYTES)];
+} spinlock_cacheline_t __attribute__ ((aligned(SMP_CACHE_BYTES)));
+
+
#elif !defined(spin_lock_init) /* !SMP and spin_lock_init not previously
defined (e.g. by including asm/spinlock.h */

--- linux/include/linux/swap.h.orig Thu Sep 6 14:38:01 2001
+++ linux/include/linux/swap.h Thu Sep 6 16:38:02 2001
@@ -88,7 +88,13 @@
extern struct address_space swapper_space;
extern atomic_t page_cache_size;
extern atomic_t buffermem_pages;
-extern spinlock_t pagecache_lock;
+#ifdef CONFIG_SMP
+ extern spinlock_cacheline_t pagecache_lock_cacheline;
+ #define pagecache_lock (pagecache_lock_cacheline.lock)
+#else
+ extern spinlock_t pagecache_lock;
+#endif
+
extern void __remove_inode_page(struct page *);

/* Incomplete types for prototype declarations: */
@@ -179,7 +185,12 @@
extern unsigned long swap_cache_find_success;
#endif

-extern spinlock_t pagemap_lru_lock;
+#ifdef CONFIG_SMP
+ extern spinlock_cacheline_t pagemap_lru_lock_cacheline;
+ #define pagemap_lru_lock pagemap_lru_lock_cacheline.lock
+#else
+ extern spinlock_t pagemap_lru_lock;
+#endif

/*
* Page aging defines.
--- linux/fs/buffer.c.orig Thu Sep 6 15:10:07 2001
+++ linux/fs/buffer.c Thu Sep 6 15:54:00 2001
@@ -83,13 +83,22 @@
static rwlock_t hash_table_lock = RW_LOCK_UNLOCKED;

static struct buffer_head *lru_list[NR_LIST];
-static spinlock_t lru_list_lock = SPIN_LOCK_UNLOCKED;
+
+#ifdef CONFIG_SMP
+ static spinlock_cacheline_t lru_list_lock_cacheline = {SPIN_LOCK_UNLOCKED};
+ #ifndef lru_list_lock
+ #define lru_list_lock lru_list_lock_cacheline.lock
+ #endif
+#else
+ static spinlock_t lru_list_lock = SPIN_LOCK_UNLOCKED;
+#endif
static int nr_buffers_type[NR_LIST];
static unsigned long size_buffers_type[NR_LIST];

static struct buffer_head * unused_list;
static int nr_unused_buffer_heads;
static spinlock_t unused_list_lock = SPIN_LOCK_UNLOCKED;
+
static DECLARE_WAIT_QUEUE_HEAD(buffer_wait);

struct bh_free_head {
--- linux/mm/filemap.c.orig Thu Sep 6 14:55:44 2001
+++ linux/mm/filemap.c Thu Sep 6 15:06:21 2001
@@ -45,12 +45,28 @@
unsigned int page_hash_bits;
struct page **page_hash_table;

-spinlock_t __cacheline_aligned pagecache_lock = SPIN_LOCK_UNLOCKED;
+#ifdef CONFIG_SMP
+ spinlock_cacheline_t pagecache_lock_cacheline = {SPIN_LOCK_UNLOCKED};
+ #ifndef pagecache_lock
+ #define pagecache_lock pagecache_lock_cacheline.lock
+ #endif
+#else
+ spinlock_t pagecache_lock = SPIN_LOCK_UNLOCKED;
+#endif
+
/*
* NOTE: to avoid deadlocking you must never acquire the pagecache_lock with
* the pagemap_lru_lock held.
*/
-spinlock_t __cacheline_aligned pagemap_lru_lock = SPIN_LOCK_UNLOCKED;
+#ifdef CONFIG_SMP
+ spinlock_cacheline_t pagemap_lru_lock_cacheline = {SPIN_LOCK_UNLOCKED};
+ #ifndef pagemap_lru_lock
+ #define pagemap_lru_lock pagemap_lru_lock_cacheline.lock
+ #endif
+#else
+ spinlock_t pagemap_lru_lock = SPIN_LOCK_UNLOCKED;
+#endif
+

#define CLUSTER_PAGES (1 << page_cluster)
#define CLUSTER_OFFSET(x) (((x) >> page_cluster) << page_cluster)
--- linux/mm/highmem.c.orig Thu Sep 6 14:55:54 2001
+++ linux/mm/highmem.c Thu Sep 6 15:08:22 2001
@@ -32,7 +32,14 @@
*/
static int pkmap_count[LAST_PKMAP];
static unsigned int last_pkmap_nr;
-static spinlock_t kmap_lock = SPIN_LOCK_UNLOCKED;
+#ifdef CONFIG_SMP
+ static spinlock_cacheline_t kmap_lock_cacheline = {SPIN_LOCK_UNLOCKED};
+ #ifndef kmap_lock
+ #define kmap_lock kmap_lock_cacheline.lock
+ #endif
+#else
+ static spinlock_t kmap_lock = SPIN_LOCK_UNLOCKED;
+#endif

pte_t * pkmap_page_table;

--- linux/arch/i386/kernel/smp.c.orig Thu Sep 6 14:52:01 2001
+++ linux/arch/i386/kernel/smp.c Thu Sep 6 16:04:38 2001
@@ -101,7 +101,14 @@
*/

/* The 'big kernel lock' */
+#ifdef CONFIG_SMP
+ spinlock_cacheline_t kernel_flag_cacheline = {SPIN_LOCK_UNLOCKED};
+ #ifndef kernel_flag
+ #define kernel_flag kernel_flag_cacheline.lock
+ #endif
+#else
spinlock_t kernel_flag = SPIN_LOCK_UNLOCKED;
+#endif

struct tlb_state cpu_tlbstate[NR_CPUS] = {[0 ... NR_CPUS-1] = { &init_mm, 0 }};
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
\
 
 \ /
  Last update: 2005-03-22 13:03    [W:0.052 / U:46.628 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site