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2008-02-07Add cmpxchg_local to xtensaMathieu Desnoyers
Use the architecture specific __cmpxchg_u32 for 32 bits cmpxchg)_local. Else, use the new generic cmpxchg_local (disables interrupt). Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Chris Zankel <chris@zankel.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Add cmpxchg_local to v850Mathieu Desnoyers
Use the new generic cmpxchg_local (disables interrupt). Also use the generic cmpxchg as fallback if SMP is not set. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Miles Bader <miles.bader@necel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Add cmpxchg_local to sparc64Mathieu Desnoyers
Use cmpxchg_u32 and cmpxchg_u64 for cmpxchg_local and cmpxchg64_local. For other type sizes, use the new generic cmpxchg_local (disables interrupt). Change: Since the header depends on local_irqsave/local_irqrestore, it must be included after their declaration. Actually, being below the #include <linux/irqflags.h> should be enough, and on sparc64 it is included at the beginning of system.h. So it makes sense to move it up for sparc64. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Add cmpxchg_local to sparc, move __cmpxchg to system.hMathieu Desnoyers
Move cmpxchg and add cmpxchg_local to system.h. Use the new generic cmpxchg_local (disables interrupt). Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Add cmpxchg_local to s390Mathieu Desnoyers
Use the standard __cmpxchg for every type that can be updated atomically. Use the new generic cmpxchg_local (disables interrupt) for other types. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Add cmpxchg_local to ppcGunnar Larisch
Add a local processor version of cmpxchg for ppc. Implements __cmpxchg_u32_local and uses it for 32 bits cmpxchg_local. It uses the non NMI safe cmpxchg_local_generic for 1, 2 and 8 bytes cmpxchg_local. Signed-off-by: Gunnar Larisch <gl@denx.de> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Kumar Gala <galak@gate.crashing.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Add cmpxchg_local to pariscMathieu Desnoyers
Use the new generic cmpxchg_local (disables interrupt). Also use the generic cmpxchg as fallback if SMP is not set. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Grant Grundler <grundler@parisc-linux.org> Cc: Matthew Wilcox <willy@debian.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Add cmpxchg_local to m68knommuMathieu Desnoyers
Use the new generic cmpxchg_local (disables interrupt). Also use the generic cmpxchg as fallback if SMP is not set. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Greg Ungerer <gerg@snapgear.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Add cmpxchg_local to m86kMathieu Desnoyers
Use the new generic cmpxchg_local (disables interrupt). Also use the generic cmpxchg as fallback if SMP is not set. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07local_t m32r use architecture specific cmpxchg_localMathieu Desnoyers
On m32r, use the new cmpxchg_local as primitive for the local_cmpxchg operation. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Acked-by: Hirokazu Takata <takata@linux-m32r.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Fix m32r __xchgMathieu Desnoyers
the #endif /* CONFIG_SMP */ should cover the default condition, or it may cause bad parameter to be silently missed. To make it work correctly, we have to remove the ifdef CONFIG SMP surrounding __xchg_called_with_bad_pointer declaration. Thanks to Adrian Bunk for detecting this. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Acked-by: Hirokazu Takata <takata@linux-m32r.org> Cc: Adrian Bunk <bunk@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07New cmpxchg_local (optimized for UP case) for m32rMathieu Desnoyers
Add __xchg_local, xchg_local (define), __cmpxchg_local_u32, __cmpxchg_local, cmpxchg_local(macro). cmpxchg_local and cmpxchg64_local will use the architecture specific __cmpxchg_local_u32 for 32 bits arguments, and use the generic __cmpxchg_local_generic for 8, 16 and 64 bits arguments. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Acked-by: Hirokazu Takata <takata@linux-m32r.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Add cmpxchg_local, cmpxchg64 and cmpxchg64_local to ia64Mathieu Desnoyers
Add the primitives cmpxchg_local, cmpxchg64 and cmpxchg64_local to ia64. They use cmpxchg_acq as underlying macro, just like the already existing ia64 cmpxchg(). Changelog: ia64 cmpxchg_local coding style fix Quoting Keith Owens: As a matter of coding style, I prefer #define cmpxchg_local cmpxchg #define cmpxchg64_local cmpxchg64 Which makes it absolutely clear that they are the same code. With your patch, humans have to do a string compare of two defines to see if they are the same. Note cmpxchg is *not* a performance win vs interrupt disable / enable on IA64. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Acked-by: Christoph Lameter <clameter@sgi.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Keith Owens <kaos@ocs.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Add cmpxchg_local to h8300Mathieu Desnoyers
Use the new generic cmpxchg_local (disables interrupt). Also use the generic cmpxchg as fallback if SMP is not set. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Add cmpxchg_local to frvMathieu Desnoyers
Use the new generic cmpxchg_local (disables interrupt) for 8, 16 and 64 bits arguments. Use the 32 bits cmpxchg available on the architecture for 32 bits arguments. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Add cmpxchg_local to crisMathieu Desnoyers
Use the new generic cmpxchg_local (disables interrupt). Also use the generic cmpxchg as fallback if SMP is not set. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Mikael Starvik <starvik@axis.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Add cmpxchg_local to blackfin, replace __cmpxchg by generic cmpxchgMathieu Desnoyers
Use the new generic cmpxchg_local (disables interrupt). Also use the generic cmpxchg as fallback if SMP is not set since nobody seems to know why __cmpxchg has been implemented in assembly in the first place thather than in plain C. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Bryan Wu <bryan.wu@analog.com> Cc: Michael Frysinger <michael.frysinger@analog.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Add cmpxchg_local to avr32Mathieu Desnoyers
Use the new generic cmpxchg_local (disables interrupt) for 8, 16 and 64 bits cmpxchg_local. Use the __cmpxchg_u32 primitive for 32 bits cmpxchg_local. Note that cmpxchg only uses the __cmpxchg_u32 or __cmpxchg_u64 and will cause a linker error if called with 8 or 16 bits argument. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Acked-by: Haavard Skinnemoen <hskinnemoen@atmel.com> Cc: Haavard Skinnemoen <hskinnemoen@atmel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Add cmpxchg_local to armMathieu Desnoyers
Use the new generic cmpxchg_local (disables interrupt). Also use the generic cmpxchg as fallback if SMP is not set. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Add cmpxchg64 and cmpxchg64_local to x86_64Mathieu Desnoyers
Make sure that at least cmpxchg64_local is available on all architectures to use for unsigned long long values. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Andi Kleen <ak@muc.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Add cmpxchg64 and cmpxchg64_local to powerpcMathieu Desnoyers
Make sure that at least cmpxchg64_local is available on all architectures to use for unsigned long long values. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Acked-by: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Add cmpxchg64 and cmpxchg64_local to mipsMathieu Desnoyers
Make sure that at least cmpxchg64_local is available on all architectures to use for unsigned long long values. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Add cmpxchg64 and cmpxchg64_local to alphaMathieu Desnoyers
Make sure that at least cmpxchg64_local is available on all architectures to use for unsigned long long values. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Add cmpxchg_local to asm-generic for per cpu atomic operationsMathieu Desnoyers
Emulates the cmpxchg_local by disabling interrupts around variable modification. This is not reentrant wrt NMIs and MCEs. It is only protected against normal interrupts, but this is enough for architectures without such interrupt sources or if used in a context where the data is not shared with such handlers. It can be used as a fallback for architectures lacking a real cmpxchg instruction. For architectures that have a real cmpxchg but does not have NMIs or MCE, testing which of the generic vs architecture specific cmpxchg is the fastest should be done. asm-generic/cmpxchg.h defines a cmpxchg that uses cmpxchg_local. It is meant to be used as a cmpxchg fallback for architectures that do not support SMP. * Patch series comments Using cmpxchg_local shows a performance improvements of the fast path goes from a 66% speedup on a Pentium 4 to a 14% speedup on AMD64. In detail: Tested-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Measurements on a Pentium4, 3GHz, Hyperthread. SLUB Performance testing ======================== 1. Kmalloc: Repeatedly allocate then free test * slub HEAD, test 1 kmalloc(8) = 201 cycles kfree = 351 cycles kmalloc(16) = 198 cycles kfree = 359 cycles kmalloc(32) = 200 cycles kfree = 381 cycles kmalloc(64) = 224 cycles kfree = 394 cycles kmalloc(128) = 285 cycles kfree = 424 cycles kmalloc(256) = 411 cycles kfree = 546 cycles kmalloc(512) = 480 cycles kfree = 619 cycles kmalloc(1024) = 623 cycles kfree = 750 cycles kmalloc(2048) = 686 cycles kfree = 811 cycles kmalloc(4096) = 482 cycles kfree = 538 cycles kmalloc(8192) = 680 cycles kfree = 734 cycles kmalloc(16384) = 713 cycles kfree = 843 cycles * Slub HEAD, test 2 kmalloc(8) = 190 cycles kfree = 351 cycles kmalloc(16) = 195 cycles kfree = 360 cycles kmalloc(32) = 201 cycles kfree = 370 cycles kmalloc(64) = 245 cycles kfree = 389 cycles kmalloc(128) = 283 cycles kfree = 413 cycles kmalloc(256) = 409 cycles kfree = 547 cycles kmalloc(512) = 476 cycles kfree = 616 cycles kmalloc(1024) = 628 cycles kfree = 753 cycles kmalloc(2048) = 684 cycles kfree = 811 cycles kmalloc(4096) = 480 cycles kfree = 539 cycles kmalloc(8192) = 661 cycles kfree = 746 cycles kmalloc(16384) = 741 cycles kfree = 856 cycles * cmpxchg_local Slub test kmalloc(8) = 83 cycles kfree = 363 cycles kmalloc(16) = 85 cycles kfree = 372 cycles kmalloc(32) = 92 cycles kfree = 377 cycles kmalloc(64) = 115 cycles kfree = 397 cycles kmalloc(128) = 179 cycles kfree = 438 cycles kmalloc(256) = 314 cycles kfree = 564 cycles kmalloc(512) = 398 cycles kfree = 615 cycles kmalloc(1024) = 573 cycles kfree = 745 cycles kmalloc(2048) = 629 cycles kfree = 816 cycles kmalloc(4096) = 473 cycles kfree = 548 cycles kmalloc(8192) = 659 cycles kfree = 745 cycles kmalloc(16384) = 724 cycles kfree = 843 cycles 2. Kmalloc: alloc/free test * slub HEAD, test 1 kmalloc(8)/kfree = 322 cycles kmalloc(16)/kfree = 318 cycles kmalloc(32)/kfree = 318 cycles kmalloc(64)/kfree = 325 cycles kmalloc(128)/kfree = 318 cycles kmalloc(256)/kfree = 328 cycles kmalloc(512)/kfree = 328 cycles kmalloc(1024)/kfree = 328 cycles kmalloc(2048)/kfree = 328 cycles kmalloc(4096)/kfree = 678 cycles kmalloc(8192)/kfree = 1013 cycles kmalloc(16384)/kfree = 1157 cycles * Slub HEAD, test 2 kmalloc(8)/kfree = 323 cycles kmalloc(16)/kfree = 318 cycles kmalloc(32)/kfree = 318 cycles kmalloc(64)/kfree = 318 cycles kmalloc(128)/kfree = 318 cycles kmalloc(256)/kfree = 328 cycles kmalloc(512)/kfree = 328 cycles kmalloc(1024)/kfree = 328 cycles kmalloc(2048)/kfree = 328 cycles kmalloc(4096)/kfree = 648 cycles kmalloc(8192)/kfree = 1009 cycles kmalloc(16384)/kfree = 1105 cycles * cmpxchg_local Slub test kmalloc(8)/kfree = 112 cycles kmalloc(16)/kfree = 103 cycles kmalloc(32)/kfree = 103 cycles kmalloc(64)/kfree = 103 cycles kmalloc(128)/kfree = 112 cycles kmalloc(256)/kfree = 111 cycles kmalloc(512)/kfree = 111 cycles kmalloc(1024)/kfree = 111 cycles kmalloc(2048)/kfree = 121 cycles kmalloc(4096)/kfree = 650 cycles kmalloc(8192)/kfree = 1042 cycles kmalloc(16384)/kfree = 1149 cycles Tested-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Measurements on a AMD64 2.0 GHz dual-core In this test, we seem to remove 10 cycles from the kmalloc fast path. On small allocations, it gives a 14% performance increase. kfree fast path also seems to have a 10 cycles improvement. 1. Kmalloc: Repeatedly allocate then free test * cmpxchg_local slub kmalloc(8) = 63 cycles kfree = 126 cycles kmalloc(16) = 66 cycles kfree = 129 cycles kmalloc(32) = 76 cycles kfree = 138 cycles kmalloc(64) = 100 cycles kfree = 288 cycles kmalloc(128) = 128 cycles kfree = 309 cycles kmalloc(256) = 170 cycles kfree = 315 cycles kmalloc(512) = 221 cycles kfree = 357 cycles kmalloc(1024) = 324 cycles kfree = 393 cycles kmalloc(2048) = 354 cycles kfree = 440 cycles kmalloc(4096) = 394 cycles kfree = 330 cycles kmalloc(8192) = 523 cycles kfree = 481 cycles kmalloc(16384) = 643 cycles kfree = 649 cycles * Base kmalloc(8) = 74 cycles kfree = 113 cycles kmalloc(16) = 76 cycles kfree = 116 cycles kmalloc(32) = 85 cycles kfree = 133 cycles kmalloc(64) = 111 cycles kfree = 279 cycles kmalloc(128) = 138 cycles kfree = 294 cycles kmalloc(256) = 181 cycles kfree = 304 cycles kmalloc(512) = 237 cycles kfree = 327 cycles kmalloc(1024) = 340 cycles kfree = 379 cycles kmalloc(2048) = 378 cycles kfree = 433 cycles kmalloc(4096) = 399 cycles kfree = 329 cycles kmalloc(8192) = 528 cycles kfree = 624 cycles kmalloc(16384) = 651 cycles kfree = 737 cycles 2. Kmalloc: alloc/free test * cmpxchg_local slub kmalloc(8)/kfree = 96 cycles kmalloc(16)/kfree = 97 cycles kmalloc(32)/kfree = 97 cycles kmalloc(64)/kfree = 97 cycles kmalloc(128)/kfree = 97 cycles kmalloc(256)/kfree = 105 cycles kmalloc(512)/kfree = 108 cycles kmalloc(1024)/kfree = 105 cycles kmalloc(2048)/kfree = 107 cycles kmalloc(4096)/kfree = 390 cycles kmalloc(8192)/kfree = 626 cycles kmalloc(16384)/kfree = 662 cycles * Base kmalloc(8)/kfree = 116 cycles kmalloc(16)/kfree = 116 cycles kmalloc(32)/kfree = 116 cycles kmalloc(64)/kfree = 116 cycles kmalloc(128)/kfree = 116 cycles kmalloc(256)/kfree = 126 cycles kmalloc(512)/kfree = 126 cycles kmalloc(1024)/kfree = 126 cycles kmalloc(2048)/kfree = 126 cycles kmalloc(4096)/kfree = 384 cycles kmalloc(8192)/kfree = 749 cycles kmalloc(16384)/kfree = 786 cycles Tested-by: Christoph Lameter <clameter@sgi.com> I can confirm Mathieus' measurement now: Athlon64: regular NUMA/discontig 1. Kmalloc: Repeatedly allocate then free test 10000 times kmalloc(8) -> 79 cycles kfree -> 92 cycles 10000 times kmalloc(16) -> 79 cycles kfree -> 93 cycles 10000 times kmalloc(32) -> 88 cycles kfree -> 95 cycles 10000 times kmalloc(64) -> 124 cycles kfree -> 132 cycles 10000 times kmalloc(128) -> 157 cycles kfree -> 247 cycles 10000 times kmalloc(256) -> 200 cycles kfree -> 257 cycles 10000 times kmalloc(512) -> 250 cycles kfree -> 277 cycles 10000 times kmalloc(1024) -> 337 cycles kfree -> 314 cycles 10000 times kmalloc(2048) -> 365 cycles kfree -> 330 cycles 10000 times kmalloc(4096) -> 352 cycles kfree -> 240 cycles 10000 times kmalloc(8192) -> 456 cycles kfree -> 340 cycles 10000 times kmalloc(16384) -> 646 cycles kfree -> 471 cycles 2. Kmalloc: alloc/free test 10000 times kmalloc(8)/kfree -> 124 cycles 10000 times kmalloc(16)/kfree -> 124 cycles 10000 times kmalloc(32)/kfree -> 124 cycles 10000 times kmalloc(64)/kfree -> 124 cycles 10000 times kmalloc(128)/kfree -> 124 cycles 10000 times kmalloc(256)/kfree -> 132 cycles 10000 times kmalloc(512)/kfree -> 132 cycles 10000 times kmalloc(1024)/kfree -> 132 cycles 10000 times kmalloc(2048)/kfree -> 132 cycles 10000 times kmalloc(4096)/kfree -> 319 cycles 10000 times kmalloc(8192)/kfree -> 486 cycles 10000 times kmalloc(16384)/kfree -> 539 cycles cmpxchg_local NUMA/discontig 1. Kmalloc: Repeatedly allocate then free test 10000 times kmalloc(8) -> 55 cycles kfree -> 90 cycles 10000 times kmalloc(16) -> 55 cycles kfree -> 92 cycles 10000 times kmalloc(32) -> 70 cycles kfree -> 91 cycles 10000 times kmalloc(64) -> 100 cycles kfree -> 141 cycles 10000 times kmalloc(128) -> 128 cycles kfree -> 233 cycles 10000 times kmalloc(256) -> 172 cycles kfree -> 251 cycles 10000 times kmalloc(512) -> 225 cycles kfree -> 275 cycles 10000 times kmalloc(1024) -> 325 cycles kfree -> 311 cycles 10000 times kmalloc(2048) -> 346 cycles kfree -> 330 cycles 10000 times kmalloc(4096) -> 351 cycles kfree -> 238 cycles 10000 times kmalloc(8192) -> 450 cycles kfree -> 342 cycles 10000 times kmalloc(16384) -> 630 cycles kfree -> 546 cycles 2. Kmalloc: alloc/free test 10000 times kmalloc(8)/kfree -> 81 cycles 10000 times kmalloc(16)/kfree -> 81 cycles 10000 times kmalloc(32)/kfree -> 81 cycles 10000 times kmalloc(64)/kfree -> 81 cycles 10000 times kmalloc(128)/kfree -> 81 cycles 10000 times kmalloc(256)/kfree -> 91 cycles 10000 times kmalloc(512)/kfree -> 90 cycles 10000 times kmalloc(1024)/kfree -> 91 cycles 10000 times kmalloc(2048)/kfree -> 90 cycles 10000 times kmalloc(4096)/kfree -> 318 cycles 10000 times kmalloc(8192)/kfree -> 483 cycles 10000 times kmalloc(16384)/kfree -> 536 cycles Changelog: - Ran though checkpatch. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Sanitize the type of struct user.u_ar0H. Peter Anvin
struct user.u_ar0 is defined to contain a pointer offset on all architectures in which it is defined (all architectures which define an a.out format except SPARC.) However, it has a pointer type in the headers, which is pointless -- <asm/user.h> is not exported to userspace, and it just makes the code messy. Redefine the field as "unsigned long" (which is the same size as a pointer on all Linux architectures) and change the setting code to user offsetof() instead of hand-coded arithmetic. Cc: Linux Arch Mailing List <linux-arch@vger.kernel.org> Cc: Bryan Wu <bryan.wu@analog.com> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Lennert Buytenhek <kernel@wantstofly.org> Cc: Håvard Skinnemoen <hskinnemoen@atmel.com> Cc: Mikael Starvik <starvik@axis.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Tony Luck <tony.luck@intel.com> Cc: Hirokazu Takata <takata@linux-m32r.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Unexport asm/page.hKirill A. Shutemov
Do not export asm/page.h during make headers_install. This removes PAGE_SIZE from userspace headers. Signed-off-by: Kirill A. Shutemov <k.shutemov@gmail.com> Reviewed-by: David Woodhouse <dwmw2@infradead.org> Cc: David Howells <dhowells@redhat.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Unexport asm/elf.hKirill A. Shutemov
Do not export asm/elf.h during make headers_install. Signed-off-by: Kirill A. Shutemov <k.shutemov@gmail.com> Reviewed-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Cleanup asm/{elf,page,user}.h: #ifdef __KERNEL__ is no longer neededKirill A. Shutemov
asm/elf.h, asm/page.h and asm/user.h don't export to userspace now, so we can drop #ifdef __KERNEL__ for them. [k.shutemov@gmail.com: remove #ifdef __KERNEL_] Signed-off-by: Kirill A. Shutemov <k.shutemov@gmail.com> Reviewed-by: David Woodhouse <dwmw2@infradead.org> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Kirill A. Shutemov <k.shutemov@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Unexport asm/user.h and linux/user.hKirill A. Shutemov
Do not export asm/user.h and linux/user.h during make headers_install. Signed-off-by: Kirill A. Shutemov <k.shutemov@gmail.com> Reviewed-by: David Woodhouse <dwmw2@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Acked-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07iget: remove iget() and the read_inode() super op as being obsoleteDavid Howells
Remove the old iget() call and the read_inode() superblock operation it uses as these are really obsolete, and the use of read_inode() does not produce proper error handling (no distinction between ENOMEM and EIO when marking an inode bad). Furthermore, this removes the temptation to use iget() to find an inode by number in a filesystem from code outside that filesystem. iget_locked() should be used instead. A new function is added in an earlier patch (iget_failed) that is to be called to mark an inode as bad, unlock it and release it should the get routine fail. Mark iget() and read_inode() as being obsolete and remove references to them from the documentation. Typically a filesystem will be modified such that the read_inode function becomes an internal iget function, for example the following: void thingyfs_read_inode(struct inode *inode) { ... } would be changed into something like: struct inode *thingyfs_iget(struct super_block *sp, unsigned long ino) { struct inode *inode; int ret; inode = iget_locked(sb, ino); if (!inode) return ERR_PTR(-ENOMEM); if (!(inode->i_state & I_NEW)) return inode; ... unlock_new_inode(inode); return inode; error: iget_failed(inode); return ERR_PTR(ret); } and then thingyfs_iget() would be called rather than iget(), for example: ret = -EINVAL; inode = iget(sb, ino); if (!inode || is_bad_inode(inode)) goto error; becomes: inode = thingyfs_iget(sb, ino); if (IS_ERR(inode)) { ret = PTR_ERR(inode); goto error; } Note that is_bad_inode() does not need to be called. The error returned by thingyfs_iget() should render it unnecessary. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07iget: stop QNX4 from using iget() and read_inode()David Howells
Stop the QNX4 filesystem from using iget() and read_inode(). Replace qnx4_read_inode() with qnx4_iget(), and call that instead of iget(). qnx4_iget() then uses iget_locked() directly and returns a proper error code instead of an inode in the event of an error. qnx4_fill_super() returns any error incurred when getting the root inode instead of EINVAL. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: David Howells <dhowells@redhat.com> Cc: Anders Larsen <al@alarsen.net> Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07iget: stop EXT4 from using iget() and read_inode()David Howells
Stop the EXT4 filesystem from using iget() and read_inode(). Replace ext4_read_inode() with ext4_iget(), and call that instead of iget(). ext4_iget() then uses iget_locked() directly and returns a proper error code instead of an inode in the event of an error. ext4_fill_super() returns any error incurred when getting the root inode instead of EINVAL. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: "Theodore Ts'o" <tytso@mit.edu> Acked-by: Jan Kara <jack@suse.cz> Cc: <linux-ext4@vger.kernel.org> Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07iget: stop EXT3 from using iget() and read_inode()David Howells
Stop the EXT3 filesystem from using iget() and read_inode(). Replace ext3_read_inode() with ext3_iget(), and call that instead of iget(). ext3_iget() then uses iget_locked() directly and returns a proper error code instead of an inode in the event of an error. ext3_fill_super() returns any error incurred when getting the root inode instead of EINVAL. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: "Theodore Ts'o" <tytso@mit.edu> Acked-by: Jan Kara <jack@suse.cz> Cc: <linux-ext4@vger.kernel.org> Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07iget: stop EFS from using iget() and read_inode()David Howells
Stop the EFS filesystem from using iget() and read_inode(). Replace efs_read_inode() with efs_iget(), and call that instead of iget(). efs_iget() then uses iget_locked() directly and returns a proper error code instead of an inode in the event of an error. efs_fill_super() returns any error incurred when getting the root inode instead of EACCES. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07iget: introduce a function to register iget failureDavid Howells
Introduce a function to register failure in an inode construction path. This includes marking the inode under construction as bad, unlocking it and releasing it. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Add an ERR_CAST() function to complement ERR_PTR and co.David Howells
Add an ERR_CAST() function to complement ERR_PTR and co. for the purposes of casting an error entyped as one pointer type to an error of another pointer type whilst making it explicit as to what is going on. This provides a replacement for the ERR_PTR(PTR_ERR(p)) construct. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07vmcoreinfo: add "VMCOREINFO_" to all the call for vmcoreinfo_append_str()Ken'ichi Ohmichi
For readability, all the calls to vmcoreinfo_append_str() are changed to macros having a prefix "VMCOREINFO_". This discussion is the following: http://www.ussg.iu.edu/hypermail/linux/kernel/0709.3/0584.html Signed-off-by: Ken'ichi Ohmichi <oomichi@mxs.nes.nec.co.jp> Acked-by: Simon Horman <horms@verge.net.au> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07vmcoreinfo: use the existing offsetof() for VMCOREINFO_OFFSET()Ken'ichi Ohmichi
It is better that the existing offsetof() is used for VMCOREINFO_OFFSET(). This discussion is the following: http://www.ussg.iu.edu/hypermail/linux/kernel/0709.3/0584.html Signed-off-by: Ken'ichi Ohmichi <oomichi@mxs.nes.nec.co.jp> Acked-by: Simon Horman <horms@verge.net.au> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07vmcoreinfo: rename vmcoreinfo's macros returning the sizeKen'ichi Ohmichi
This patchset is for the vmcoreinfo data. The vmcoreinfo data has the minimum debugging information only for dump filtering. makedumpfile (dump filtering command) gets it to distinguish unnecessary pages, and makedumpfile creates a small dumpfile. This patch: VMCOREINFO_SIZE() should be renamed VMCOREINFO_STRUCT_SIZE() since it's always returning the size of the struct with a given name. This change would allow VMCOREINFO_TYPEDEF_SIZE() to simply become VMCOREINFO_SIZE() since it need not be used exclusively for typedefs. This discussion is the following: http://www.ussg.iu.edu/hypermail/linux/kernel/0709.3/0582.html Signed-off-by: Ken'ichi Ohmichi <oomichi@mxs.nes.nec.co.jp> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Simon Horman <horms@verge.net.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Introduce flags for reserve_bootmem()Bernhard Walle
This patchset adds a flags variable to reserve_bootmem() and uses the BOOTMEM_EXCLUSIVE flag in crashkernel reservation code to detect collisions between crashkernel area and already used memory. This patch: Change the reserve_bootmem() function to accept a new flag BOOTMEM_EXCLUSIVE. If that flag is set, the function returns with -EBUSY if the memory already has been reserved in the past. This is to avoid conflicts. Because that code runs before SMP initialisation, there's no race condition inside reserve_bootmem_core(). [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: fix powerpc build] Signed-off-by: Bernhard Walle <bwalle@suse.de> Cc: <linux-arch@vger.kernel.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07ASIC3 driverSamuel Ortiz
This is a patch for the Compaq ASIC3 multi function chip, found in many PDAs (iPAQs, HTCs...). It is a simplified version of Paul Sokolovsky's first proposal [1]. With this code, it is basically a GPIO and IRQ expander. My plan is to add more features once this patch gets reviewed and accepted. [1] http://lkml.org/lkml/2007/5/1/46 Signed-off-by: Samuel Ortiz <sameo@openedhand.com> Cc: Paul Sokolovsky <pmiscml@gmail.com> Cc: Ben Dooks <ben@trinity.fluff.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07hotplug cpu: move tasks in empty cpusets to parentCliff Wickman
This patch corrects a situation that occurs when one disables all the cpus in a cpuset. Currently, the disabled (cpu-less) cpuset inherits the cpus of its parent, which is incorrect because it may then overlap its cpu-exclusive sibling. Tasks of an empty cpuset should be moved to the cpuset which is the parent of their current cpuset. Or if the parent cpuset has no cpus, to its parent, etc. And the empty cpuset should be released (if it is flagged notify_on_release). Depends on the cgroup_scan_tasks() function (proposed by David Rientjes) to iterate through all tasks in the cpu-less cpuset. We are deliberately avoiding a walk of the tasklist. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Cliff Wickman <cpw@sgi.com> Cc: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07cgroups: mechanism to process each task in a cgroupCliff Wickman
Provide cgroup_scan_tasks(), which iterates through every task in a cgroup, calling a test function and a process function for each. And call the process function without holding the css_set_lock lock. The idea is David Rientjes', predicting that such a function will make it much easier in the future to extend things that require access to each task in a cgroup without holding the lock, [akpm@linux-foundation.org: cleanup] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Cliff Wickman <cpw@sgi.com> Cc: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07Memory controller remove control_type featureBalbir Singh
Based on the discussion at http://lkml.org/lkml/2007/12/20/383, it was felt that control_type might not be a good thing to implement right away. We can add this flexibility at a later point when required. Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07per-zone and reclaim enhancements for memory controller: calculate the ↵KAMEZAWA Hiroyuki
number of pages to be scanned per cgroup Define function for calculating the number of scan target on each Zone/LRU. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: David Rientjes <rientjes@google.com> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Kirill Korotaev <dev@sw.ru> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Paul Menage <menage@google.com> Cc: Pavel Emelianov <xemul@openvz.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07per-zone and reclaim enhancements for memory controller: remember reclaim ↵KAMEZAWA Hiroyuki
priority in memory cgroup Functions to remember reclaim priority per cgroup (as zone->prev_priority) [akpm@linux-foundation.org: build fixes] [akpm@linux-foundation.org: more build fixes] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: David Rientjes <rientjes@google.com> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Kirill Korotaev <dev@sw.ru> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Paul Menage <menage@google.com> Cc: Pavel Emelianov <xemul@openvz.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07per-zone and reclaim enhancements for memory controller: calculate ↵KAMEZAWA Hiroyuki
active/inactive imbalance per cgroup Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: David Rientjes <rientjes@google.com> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Kirill Korotaev <dev@sw.ru> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Paul Menage <menage@google.com> Cc: Pavel Emelianov <xemul@openvz.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07per-zone and reclaim enhancements for memory controller: calculate ↵KAMEZAWA Hiroyuki
mapper_ratio per cgroup Define function for calculating mapped_ratio in memory cgroup. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: David Rientjes <rientjes@google.com> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Kirill Korotaev <dev@sw.ru> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Paul Menage <menage@google.com> Cc: Pavel Emelianov <xemul@openvz.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07memory cgroup enhancements: add- pre_destroy() handlerKAMEZAWA Hiroyuki
Add a handler "pre_destroy" to cgroup_subsys. It is called before cgroup_rmdir() checks all subsys's refcnt. I think this is useful for subsys which have some extra refs even if there are no tasks in cgroup. By adding pre_destroy(), the kernel keeps the rule "destroy() against subsystem is called only when refcnt=0." and allows css ref to be used by other objects than tasks. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: David Rientjes <rientjes@google.com> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Kirill Korotaev <dev@sw.ru> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Paul Menage <menage@google.com> Cc: Pavel Emelianov <xemul@openvz.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07bugfix for memory cgroup controller: migration under memory controller fixKAMEZAWA Hiroyuki
While using memory control cgroup, page-migration under it works as following. == 1. uncharge all refs at try to unmap. 2. charge regs again remove_migration_ptes() == This is simple but has following problems. == The page is uncharged and charged back again if *mapped*. - This means that cgroup before migration can be different from one after migration - If page is not mapped but charged as page cache, charge is just ignored (because not mapped, it will not be uncharged before migration) This is memory leak. == This patch tries to keep memory cgroup at page migration by increasing one refcnt during it. 3 functions are added. mem_cgroup_prepare_migration() --- increase refcnt of page->page_cgroup mem_cgroup_end_migration() --- decrease refcnt of page->page_cgroup mem_cgroup_page_migration() --- copy page->page_cgroup from old page to new page. During migration - old page is under PG_locked. - new page is under PG_locked, too. - both old page and new page is not on LRU. These 3 facts guarantee that page_cgroup() migration has no race. Tested and worked well in x86_64/fake-NUMA box. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelianov <xemul@openvz.org> Cc: Paul Menage <menage@google.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Kirill Korotaev <dev@sw.ru> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: David Rientjes <rientjes@google.com> Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>