From: Christoph Lameter <cl@linux.com>
To: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: David Rientjes <rientjes@google.com>,
Hugh Dickins <hughd@google.com>,
Eric Dumazet <eric.dumazet@gmail.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
linux-mm@kvack.org
Subject: [slubllv333num@/21] x86: Add support for cmpxchg_double
Date: Fri, 15 Apr 2011 15:12:55 -0500 [thread overview]
Message-ID: <20110415201300.189983463@linux.com> (raw)
In-Reply-To: 20110415201246.096634892@linux.com
[-- Attachment #1: cmpxchg_double_x86 --]
[-- Type: text/plain, Size: 6014 bytes --]
A simple implementation that only supports the word size and does not
have a fallback mode (would require a spinlock).
And 32 and 64 bit support for cmpxchg_double. cmpxchg double uses
the cmpxchg8b or cmpxchg16b instruction on x86 processors to compare
and swap 2 machine words. This allows lockless algorithms to move more
context information through critical sections.
Set a flag CONFIG_CMPXCHG_DOUBLE to signal the support of that feature
during kernel builds.
Signed-off-by: Christoph Lameter <cl@linux.com>
---
arch/x86/Kconfig.cpu | 3 ++
arch/x86/include/asm/cmpxchg_32.h | 46 ++++++++++++++++++++++++++++++++++++++
arch/x86/include/asm/cmpxchg_64.h | 45 +++++++++++++++++++++++++++++++++++++
arch/x86/include/asm/cpufeature.h | 1
4 files changed, 95 insertions(+)
Index: linux-2.6/arch/x86/include/asm/cmpxchg_64.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/cmpxchg_64.h 2011-04-13 15:19:53.000000000 -0500
+++ linux-2.6/arch/x86/include/asm/cmpxchg_64.h 2011-04-15 13:14:45.000000000 -0500
@@ -151,4 +151,49 @@ extern void __cmpxchg_wrong_size(void);
cmpxchg_local((ptr), (o), (n)); \
})
+#define cmpxchg16b(ptr, o1, o2, n1, n2) \
+({ \
+ char __ret; \
+ __typeof__(o2) __junk; \
+ __typeof__(*(ptr)) __old1 = (o1); \
+ __typeof__(o2) __old2 = (o2); \
+ __typeof__(*(ptr)) __new1 = (n1); \
+ __typeof__(o2) __new2 = (n2); \
+ asm volatile(LOCK_PREFIX_HERE "lock; cmpxchg16b (%%rsi);setz %1" \
+ : "=d"(__junk), "=a"(__ret) \
+ : "S"(ptr), "b"(__new1), "c"(__new2), \
+ "a"(__old1), "d"(__old2)); \
+ __ret; })
+
+
+#define cmpxchg16b_local(ptr, o1, o2, n1, n2) \
+({ \
+ char __ret; \
+ __typeof__(o2) __junk; \
+ __typeof__(*(ptr)) __old1 = (o1); \
+ __typeof__(o2) __old2 = (o2); \
+ __typeof__(*(ptr)) __new1 = (n1); \
+ __typeof__(o2) __new2 = (n2); \
+ asm volatile("cmpxchg16b (%%rsi)\n\t\tsetz %1\n\t" \
+ : "=d"(__junk)_, "=a"(__ret) \
+ : "S"((ptr)), "b"(__new1), "c"(__new2), \
+ "a"(__old1), "d"(__old2)); \
+ __ret; })
+
+#define cmpxchg_double(ptr, o1, o2, n1, n2) \
+({ \
+ BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
+ VM_BUG_ON((unsigned long)(ptr) % 16); \
+ cmpxchg16b((ptr), (o1), (o2), (n1), (n2)); \
+})
+
+#define cmpxchg_double_local(ptr, o1, o2, n1, n2) \
+({ \
+ BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
+ VM_BUG_ON((unsigned long)(ptr) % 16); \
+ cmpxchg16b_local((ptr), (o1), (o2), (n1), (n2)); \
+})
+
+#define system_has_cmpxchg_double() cpu_has_cx16
+
#endif /* _ASM_X86_CMPXCHG_64_H */
Index: linux-2.6/arch/x86/include/asm/cmpxchg_32.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/cmpxchg_32.h 2011-04-13 15:19:53.000000000 -0500
+++ linux-2.6/arch/x86/include/asm/cmpxchg_32.h 2011-04-15 13:14:45.000000000 -0500
@@ -280,4 +280,50 @@ static inline unsigned long cmpxchg_386(
#endif
+#define cmpxchg8b(ptr, o1, o2, n1, n2) \
+({ \
+ char __ret; \
+ __typeof__(o2) __dummy; \
+ __typeof__(*(ptr)) __old1 = (o1); \
+ __typeof__(o2) __old2 = (o2); \
+ __typeof__(*(ptr)) __new1 = (n1); \
+ __typeof__(o2) __new2 = (n2); \
+ asm volatile(LOCK_PREFIX_HERE "lock; cmpxchg8b (%%esi); setz %1"\
+ : "d="(__dummy), "=a" (__ret) \
+ : "S" ((ptr)), "a" (__old1), "d"(__old2), \
+ "b" (__new1), "c" (__new2) \
+ : "memory"); \
+ __ret; })
+
+
+#define cmpxchg8b_local(ptr, o1, o2, n1, n2) \
+({ \
+ char __ret; \
+ __typeof__(o2) __dummy; \
+ __typeof__(*(ptr)) __old1 = (o1); \
+ __typeof__(o2) __old2 = (o2); \
+ __typeof__(*(ptr)) __new1 = (n1); \
+ __typeof__(o2) __new2 = (n2); \
+ asm volatile("cmpxchg8b (%%esi); tsetz %1" \
+ : "d="(__dummy), "=a"(__ret) \
+ : "S" ((ptr)), "a" (__old), "d"(__old2), \
+ "b" (__new1), "c" (__new2), \
+ : "memory"); \
+ __ret; })
+
+
+#define cmpxchg_double(ptr, o1, o2, n1, n2) \
+({ \
+ BUILD_BUG_ON(sizeof(*(ptr)) != 4); \
+ VM_BUG_ON((unsigned long)(ptr) % 8); \
+ cmpxchg8b((ptr), (o1), (o2), (n1), (n2)); \
+})
+
+#define cmpxchg_double_local(ptr, o1, o2, n1, n2) \
+({ \
+ BUILD_BUG_ON(sizeof(*(ptr)) != 4); \
+ VM_BUG_ON((unsigned long)(ptr) % 8); \
+ cmpxchg16b_local((ptr), (o1), (o2), (n1), (n2)); \
+})
+
#endif /* _ASM_X86_CMPXCHG_32_H */
Index: linux-2.6/arch/x86/Kconfig.cpu
===================================================================
--- linux-2.6.orig/arch/x86/Kconfig.cpu 2011-04-13 15:19:53.000000000 -0500
+++ linux-2.6/arch/x86/Kconfig.cpu 2011-04-15 13:14:45.000000000 -0500
@@ -308,6 +308,9 @@ config X86_CMPXCHG
config CMPXCHG_LOCAL
def_bool X86_64 || (X86_32 && !M386)
+config CMPXCHG_DOUBLE
+ def_bool X86_64 || (X86_32 && !M386)
+
config X86_L1_CACHE_SHIFT
int
default "7" if MPENTIUM4 || MPSC
Index: linux-2.6/arch/x86/include/asm/cpufeature.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/cpufeature.h 2011-04-15 12:51:51.000000000 -0500
+++ linux-2.6/arch/x86/include/asm/cpufeature.h 2011-04-15 13:14:45.000000000 -0500
@@ -286,6 +286,7 @@ extern const char * const x86_power_flag
#define cpu_has_hypervisor boot_cpu_has(X86_FEATURE_HYPERVISOR)
#define cpu_has_pclmulqdq boot_cpu_has(X86_FEATURE_PCLMULQDQ)
#define cpu_has_perfctr_core boot_cpu_has(X86_FEATURE_PERFCTR_CORE)
+#define cpu_has_cx16 boot_cpu_has(X86_FEATURE_CX16)
#if defined(CONFIG_X86_INVLPG) || defined(CONFIG_X86_64)
# define cpu_has_invlpg 1
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2011-04-15 20:13 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-15 20:12 [slubllv333num@/21] SLUB: Lockless freelists for objects V3 Christoph Lameter
2011-04-15 20:12 ` [slubllv333num@/21] slub: Use NUMA_NO_NODE in get_partial Christoph Lameter
2011-04-15 20:12 ` [slubllv333num@/21] slub: get_map() function to establish map of free objects in a slab Christoph Lameter
2011-04-15 20:12 ` [slubllv333num@/21] slub: Eliminate repeated use of c->page through a new page variable Christoph Lameter
2011-04-15 20:12 ` [slubllv333num@/21] slub: Move node determination out of hotpath Christoph Lameter
2011-04-15 20:12 ` [slubllv333num@/21] slub: Move debug handlign in __slab_free Christoph Lameter
2011-04-15 20:12 ` [slubllv333num@/21] slub: Per object NUMA support Christoph Lameter
2011-04-15 20:12 ` [slubllv333num@/21] slub: Do not use frozen page flag but a bit in the page counters Christoph Lameter
2011-04-15 20:12 ` [slubllv333num@/21] slub: Move page->frozen handling near where the page->freelist handling occurs Christoph Lameter
2011-04-15 20:12 ` Christoph Lameter [this message]
2011-04-15 20:12 ` [slubllv333num@/21] mm: Rearrange struct page Christoph Lameter
2011-04-15 20:12 ` [slubllv333num@/21] slub: Add cmpxchg_double_slab() Christoph Lameter
2011-04-15 20:12 ` [slubllv333num@/21] slub: explicit list_lock taking Christoph Lameter
2011-04-15 20:12 ` [slubllv333num@/21] slub: Pass kmem_cache struct to lock and freeze slab Christoph Lameter
2011-04-15 20:13 ` [slubllv333num@/21] slub: Rework allocator fastpaths Christoph Lameter
2011-04-15 20:13 ` [slubllv333num@/21] slub: Invert locking and avoid slab lock Christoph Lameter
2011-04-15 20:13 ` [slubllv333num@/21] slub: Disable interrupts in free_debug processing Christoph Lameter
2011-04-15 20:13 ` [slubllv333num@/21] slub: Avoid disabling interrupts in free slowpath Christoph Lameter
2011-04-15 20:13 ` [slubllv333num@/21] slub: Get rid of the another_slab label Christoph Lameter
2011-04-15 20:13 ` [slubllv333num@/21] slub: fast release on full slab Christoph Lameter
2011-04-15 20:13 ` [slubllv333num@/21] slub: Not necessary to check for empty slab on load_freelist Christoph Lameter
2011-04-15 20:13 ` [slubllv333num@/21] slub: update statistics for cmpxchg handling Christoph Lameter
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20110415201300.189983463@linux.com \
--to=cl@linux.com \
--cc=eric.dumazet@gmail.com \
--cc=hpa@zytor.com \
--cc=hughd@google.com \
--cc=linux-mm@kvack.org \
--cc=mathieu.desnoyers@efficios.com \
--cc=penberg@cs.helsinki.fi \
--cc=rientjes@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.