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* configfs: add show and store methods to struct configfs_attributeChristoph Hellwig2015-10-142-5/+39
| | | | | | | | | | | | Add methods to struct configfs_attribute to directly show and store attributes without adding boilerplate code to every user. In addition to the methods this also adds 3 helper macros to define read/write, read-only and write-only attributes with a single line of code. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Nicholas Bellinger <nab@linux-iscsi.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
* Linux 4.3-rc1v4.3-rc1Linus Torvalds2015-09-131-2/+2
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* Merge tag 'cris-for-4.3' of ↵Linus Torvalds2015-09-1250-421/+220
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jesper/cris Pull CRIS updates from Jesper Nilsson: "Mostly removal of old cruft of which we can use a generic version, or fixes for code not commonly run in the cris port, but also additions to enable some good debug" * tag 'cris-for-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/jesper/cris: (25 commits) CRISv10: delete unused lib/dmacopy.c CRISv10: delete unused lib/old_checksum.c CRIS: fix switch_mm() lockdep splat CRISv32: enable LOCKDEP_SUPPORT CRIS: add STACKTRACE_SUPPORT CRISv32: annotate irq enable in idle loop CRISv32: add support for irqflags tracing CRIS: UAPI: use generic types.h CRIS: UAPI: use generic shmbuf.h CRIS: UAPI: use generic msgbuf.h CRIS: UAPI: use generic socket.h CRIS: UAPI: use generic sembuf.h CRIS: UAPI: use generic sockios.h CRIS: UAPI: use generic auxvec.h CRIS: UAPI: use generic headers via Kbuild CRIS: UAPI: fix elf.h export CRIS: don't make asm/elf.h depend on asm/user.h CRIS: UAPI: fix ptrace.h CRISv32: Squash compile warnings for axisflashmap CRISv32: Add GPIO driver to the default configs ...
| * CRISv10: delete unused lib/dmacopy.cRabin Vincent2015-09-051-42/+0
| | | | | | | | | | | | | | This file is never built. Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Jesper Nilsson <jespern@axis.com>
| * CRISv10: delete unused lib/old_checksum.cRabin Vincent2015-09-051-86/+0
| | | | | | | | | | | | | | This file is never built. Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
| * CRIS: fix switch_mm() lockdep splatRabin Vincent2015-09-051-1/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With lockdep support implemented on CRISv32, we get the following splat. switch_mm() can be called both from the scheduler() (with interrupts disabled) and from flush_old_exec (via activate_mm()), with interrupts enabled. Fix it by disabling interrupts in activate_mm(), similar to powerpc and hexagon. t====================================================== [ INFO: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected ] 3.19.0-08802-g20bc9f1-dirty #323 Not tainted ------------------------------------------------------ init/1 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: (mmu_context_lock){+.+...}, at: [<c0009290>] switch_mm+0x22/0xc6 and this task is already holding: (&rq->lock){-.-.-.}, at: [<c01a0756>] __schedule+0x5e/0x648 which would create a new lock dependency: (&rq->lock){-.-.-.} -> (mmu_context_lock){+.+...} but this new dependency connects a HARDIRQ-irq-safe lock: (&rq->lock){-.-.-.} ... which became HARDIRQ-irq-safe at: [<c002b03c>] scheduler_tick+0x28/0x5e [<c0007c6c>] timer_interrupt+0x4e/0x6a [<c0043ac4>] handle_irq_event_percpu+0x54/0x13c [<c004343c>] generic_handle_irq+0x2a/0x36 to a HARDIRQ-irq-unsafe lock: (mmu_context_lock){+.+...} ... which became HARDIRQ-irq-unsafe at: ... [<c0039e60>] __lock_acquire+0x8f8/0x1d9c [<c0009290>] switch_mm+0x22/0xc6 [<c009c260>] flush_old_exec+0x500/0x5d4 [<c00da4c6>] load_elf_phdrs+0x7a/0x84 [<c00dbdb0>] load_elf_binary+0x21c/0x13b4 [<c009cdb6>] do_execve+0x22/0x2c [<c001dcf2>] ____call_usermodehelper+0x0/0x154 [<c000581e>] ret_from_kernel_thread+0xe/0x14 other info that might help us debug this: Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(mmu_context_lock); local_irq_disable(); lock(&rq->lock); lock(mmu_context_lock); <Interrupt> lock(&rq->lock); *** DEADLOCK *** 1 lock held by init/1: #0: (&rq->lock){-.-.-.}, at: [<c01a0756>] __schedule+0x5e/0x648 Call Trace: [<c019fe9e>] printk+0x0/0x4e [<c00368f8>] print_shortest_lock_dependencies+0x0/0x15c [<c0048628>] print_stack_trace+0x0/0x88 [<c0038912>] __lock_is_held+0x3e/0x5e [<c003b894>] lock_acquire+0x8a/0xcc [<c01a50c4>] _raw_spin_lock+0x44/0x7a [<c0009290>] switch_mm+0x22/0xc6 [<c01a06f8>] __schedule+0x0/0x648 [<c01a0d76>] schedule+0x36/0x7c [<c0037d04>] trace_hardirqs_on+0x0/0x1e [<c0004e18>] do_work_pending+0x30/0xd4 [<c000591a>] _work_pending+0xe/0x12 Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
| * CRISv32: enable LOCKDEP_SUPPORTRabin Vincent2015-09-051-0/+4
| | | | | | | | | | | | | | | | Now that we have stack tracing and irq flags tracing support, we can also enable lockdep support Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
| * CRIS: add STACKTRACE_SUPPORTRabin Vincent2015-09-054-0/+88
| | | | | | | | | | | | | | | | | | | | Add stacktrace support, which is required for lockdep and tracing. The stack tracing simply looks at all kernel text symbols found on the stack, similar to the trap stack dumping code, which can also be converted to use this. Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
| * CRISv32: annotate irq enable in idle loopRabin Vincent2015-09-051-2/+2
| | | | | | | | | | | | | | | | Use a call to local_irq_enable() instead of incline asm so that the irqsoff latency tracer knows that interrupts are enabled here. Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
| * CRISv32: add support for irqflags tracingRabin Vincent2015-09-053-1/+20
| | | | | | | | | | | | | | | | Add support irqflags tracing, which is required for things like lockdep and ftrace. Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
| * CRIS: UAPI: use generic types.hRabin Vincent2015-09-053-13/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | CRIS' types.h is functionally identical to the asm-generic version. Effective diff: +#ifndef _ASM_GENERIC_TYPES_H +#define _ASM_GENERIC_TYPES_H + #include <asm-generic/int-ll64.h> + +#endif Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
| * CRIS: UAPI: use generic shmbuf.hRabin Vincent2015-09-052-42/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | CRIS' shmbuf.h is equivalent to the asm-generic verison. Effective diff: -#ifndef _CRIS_SHMBUF_H -#define _CRIS_SHMBUF_H +#ifndef __ASM_GENERIC_SHMBUF_H +#define __ASM_GENERIC_SHMBUF_H + +#include <asm/bitsperlong.h> struct ipc64_perm shm_perm; size_t shm_segsz; __kernel_time_t shm_atime; +#if __BITS_PER_LONG != 64 unsigned long __unused1; +#endif __kernel_time_t shm_dtime; +#if __BITS_PER_LONG != 64 unsigned long __unused2; +#endif __kernel_time_t shm_ctime; +#if __BITS_PER_LONG != 64 unsigned long __unused3; +#endif __kernel_pid_t shm_cpid; __kernel_pid_t shm_lpid; - unsigned long shm_nattch; - unsigned long __unused4; - unsigned long __unused5; + __kernel_ulong_t shm_nattch; + __kernel_ulong_t __unused4; + __kernel_ulong_t __unused5; }; struct shminfo64 { - unsigned long shmmax; - unsigned long shmmin; - unsigned long shmmni; - unsigned long shmseg; - unsigned long shmall; - unsigned long __unused1; - unsigned long __unused2; - unsigned long __unused3; - unsigned long __unused4; + __kernel_ulong_t shmmax; + __kernel_ulong_t shmmin; + __kernel_ulong_t shmmni; + __kernel_ulong_t shmseg; + __kernel_ulong_t shmall; + __kernel_ulong_t __unused1; + __kernel_ulong_t __unused2; + __kernel_ulong_t __unused3; + __kernel_ulong_t __unused4; }; #endif Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
| * CRIS: UAPI: use generic msgbuf.hRabin Vincent2015-09-052-33/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | CRIS' msgbuf.h is equivalent to the asm-generic version. Effective diff: -#ifndef _CRIS_MSGBUF_H -#define _CRIS_MSGBUF_H - - +#ifndef __ASM_GENERIC_MSGBUF_H +#define __ASM_GENERIC_MSGBUF_H +#include <asm/bitsperlong.h> struct msqid64_ds { struct ipc64_perm msg_perm; __kernel_time_t msg_stime; +#if __BITS_PER_LONG != 64 unsigned long __unused1; +#endif __kernel_time_t msg_rtime; +#if __BITS_PER_LONG != 64 unsigned long __unused2; +#endif __kernel_time_t msg_ctime; +#if __BITS_PER_LONG != 64 unsigned long __unused3; - unsigned long msg_cbytes; - unsigned long msg_qnum; - unsigned long msg_qbytes; +#endif + __kernel_ulong_t msg_cbytes; + __kernel_ulong_t msg_qnum; + __kernel_ulong_t msg_qbytes; __kernel_pid_t msg_lspid; __kernel_pid_t msg_lrpid; - unsigned long __unused4; - unsigned long __unused5; + __kernel_ulong_t __unused4; + __kernel_ulong_t __unused5; }; #endif Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
| * CRIS: UAPI: use generic socket.hRabin Vincent2015-09-052-92/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | CRIS' socket.h is equivalent to the asm-generic version. Effective diff: -#ifndef _ASM_SOCKET_H -#define _ASM_SOCKET_H - - +#ifndef __ASM_GENERIC_SOCKET_H +#define __ASM_GENERIC_SOCKET_H #include <asm/sockios.h> #define SO_LINGER 13 #define SO_BSDCOMPAT 14 #define SO_REUSEPORT 15 +#ifndef SO_PASSCRED #define SO_PASSCRED 16 #define SO_PEERCRED 17 #define SO_RCVLOWAT 18 #define SO_SNDLOWAT 19 #define SO_RCVTIMEO 20 #define SO_SNDTIMEO 21 +#endif #define SO_SECURITY_AUTHENTICATION 22 Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
| * CRIS: UAPI: use generic sembuf.hRabin Vincent2015-09-052-25/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | CRIS's sembuf.h is equivalent to the asm-generic version. Effective diff: -#ifndef _CRIS_SEMBUF_H -#define _CRIS_SEMBUF_H +#ifndef __ASM_GENERIC_SEMBUF_H +#define __ASM_GENERIC_SEMBUF_H +#include <asm/bitsperlong.h> struct semid64_ds { struct ipc64_perm sem_perm; __kernel_time_t sem_otime; +#if __BITS_PER_LONG != 64 unsigned long __unused1; +#endif __kernel_time_t sem_ctime; +#if __BITS_PER_LONG != 64 unsigned long __unused2; +#endif unsigned long sem_nsems; unsigned long __unused3; unsigned long __unused4; Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
| * CRIS: UAPI: use generic sockios.hRabin Vincent2015-09-052-13/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | CRIS' sockios.h is equivalent to the asm-generic version. Effective diff: -#ifndef __ARCH_CRIS_SOCKIOS__ -#define __ARCH_CRIS_SOCKIOS__ +#ifndef __ASM_GENERIC_SOCKIOS_H +#define __ASM_GENERIC_SOCKIOS_H Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
| * CRIS: UAPI: use generic auxvec.hRabin Vincent2015-09-052-4/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | CRIS's auxvec.h is empty just like the asm-generic version. Effective diff: -#ifndef __ASMCRIS_AUXVEC_H -#define __ASMCRIS_AUXVEC_H +#ifndef __ASM_GENERIC_AUXVEC_H +#define __ASM_GENERIC_AUXVEC_H + Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
| * CRIS: UAPI: use generic headers via KbuildRabin Vincent2015-09-0512-31/+10
| | | | | | | | | | | | | | Use Kbuild magic to include the generic headers. Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
| * CRIS: UAPI: fix elf.h exportRabin Vincent2015-09-054-1/+8
| | | | | | | | | | | | | | | | | | CRIS userspace (uClibc for one) expects asm/elf.h to be exported but this header appears to have gone missing at some point. Move it to uapi/ and export it. Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
| * CRIS: don't make asm/elf.h depend on asm/user.hRabin Vincent2015-09-053-8/+7
| | | | | | | | | | | | | | | | We're going to export asm/elf.h; remove its dependencies on the non-exported asm/user.h and the unused asm/system.h include. Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
| * CRIS: UAPI: fix ptrace.hRabin Vincent2015-09-056-3/+8
| | | | | | | | | | | | | | | | | | | | The exported ptrace.h header on CRIS references an "arch" directory which does not exist. Fix this by having the variants in the same directory and including them conditionally, similar to other architectures. Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
| * CRISv32: Squash compile warnings for axisflashmapJesper Nilsson2015-09-051-4/+5
| | | | | | | | Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
| * CRISv32: Add GPIO driver to the default configsJesper Nilsson2015-09-054-14/+12
| | | | | | | | | | | | | | | | | | | | | | Fix a number of small issues visible when GPIO is enabled: - Correct missing default for !ETRAXFS in Kconfig - Remove information on number of bits for some Kconfigs related to the GPIO, they are different in ETRAX FS and ARTPEC-3 - Fix compile warning in ARTPEC-3 GPIO driver Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
| * CRISv32: ETRAX FS: Squash warnings in pinmux driverJesper Nilsson2015-09-051-2/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | Squash the followng warnings arch/cris/arch-v32/mach-fs/pinmux.c: In function 'crisv32_pinmux_alloc_fixed': arch/cris/arch-v32/mach-fs/pinmux.c:104:2: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement] arch/cris/arch-v32/mach-fs/pinmux.c: In function 'crisv32_pinmux_dealloc_fixed': arch/cris/arch-v32/mach-fs/pinmux.c:238:2: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement] arch/cris/arch-v32/mach-fs/pinmux.c: In function '__crisv32_pinmux_alloc': arch/cris/arch-v32/mach-fs/pinmux.c:49:1: warning: control reaches end of non-void function [-Wreturn-type] Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
| * CRIS: Wire up missing syscallsChen Gang2015-09-054-1/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The related warnings: CALL scripts/checksyscalls.sh <stdin>:1229:2: warning: #warning syscall sched_setattr not implemented [-Wcpp] <stdin>:1232:2: warning: #warning syscall sched_getattr not implemented [-Wcpp] <stdin>:1235:2: warning: #warning syscall renameat2 not implemented [-Wcpp] <stdin>:1238:2: warning: #warning syscall seccomp not implemented [-Wcpp] <stdin>:1241:2: warning: #warning syscall getrandom not implemented [-Wcpp] <stdin>:1244:2: warning: #warning syscall memfd_create not implemented [-Wcpp] <stdin>:1247:2: warning: #warning syscall bpf not implemented [-Wcpp] <stdin>:1250:2: warning: #warning syscall execveat not implemented [-Wcpp] Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com> Signed-off-by: Jesper Nilsson <jespern@axis.com>
| * CRISv32: allow CONFIG_DEBUG_BUGVERBOSERabin Vincent2015-09-051-0/+1
| | | | | | | | | | | | | | | | Support for verbose BUG reporting already exists, but the HAVE flag that allows the option to be enabled is missing. Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Jesper Nilsson <jespern@axis.com>
| * CRISv32: add unreachable() to BUG()Rabin Vincent2015-09-051-2/+9
| | | | | | | | | | | | | | | | | | | | | | Add an unreachable() in the BUG() implementations, to get rid of several warnings similar to the one below: kernel/sched/core.c: In function 'pick_next_task': kernel/sched/core.c:2690:1: warning: control reaches end of non-void function [-Wreturn-type] Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Jesper Nilsson <jespern@axis.com>
| * cris: arch-v32: gpio: Use kzalloc instead of kmalloc/memsetChristophe Jaillet2015-09-051-2/+1
| | | | | | | | | | | | | | | | Turn a kmalloc/memset into an equivalent kzalloc. Doing so also move the zero'ing of the memory outside of a mutex. Signed-off-by: Christophe Jaillet <christophe.jaillet@wanadoo.fr> Signed-off-by: Jesper Nilsson <jespern@axis.com>
* | blk: rq_data_dir() should not return a booleanLinus Torvalds2015-09-121-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | rq_data_dir() returns either READ or WRITE (0 == READ, 1 == WRITE), not a boolean value. Now, admittedly the "!= 0" doesn't really change the value (0 stays as zero, 1 stays as one), but it's not only redundant, it confuses gcc, and causes gcc to warn about the construct switch (rq_data_dir(req)) { case READ: ... case WRITE: ... that we have in a few drivers. Now, the gcc warning is silly and stupid (it seems to warn not about the switch value having a different type from the case statements, but about _any_ boolean switch value), but in this case the code itself is silly and stupid too, so let's just change it, and get rid of warnings like this: drivers/block/hd.c: In function ‘hd_request’: drivers/block/hd.c:630:11: warning: switch condition has boolean value [-Wswitch-bool] switch (rq_data_dir(req)) { The odd '!= 0' came in when "cmd_flags" got turned into a "u64" in commit 5953316dbf90 ("block: make rq->cmd_flags be 64-bit") and is presumably because the old code (that just did a logical 'and' with 1) would then end up making the type of rq_data_dir() be u64 too. But if we want to retain the old regular integer type, let's just cast the result to 'int' rather than use that rather odd '!= 0'. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Merge branch 'writeback-plugging'Linus Torvalds2015-09-121-3/+10
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix up the writeback plugging introduced in commit d353d7587d02 ("writeback: plug writeback at a high level") that then caused problems due to the unplug happening with a spinlock held. * writeback-plugging: writeback: plug writeback in wb_writeback() and writeback_inodes_wb() Revert "writeback: plug writeback at a high level"
| * | writeback: plug writeback in wb_writeback() and writeback_inodes_wb()Linus Torvalds2015-09-121-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We had to revert the pluggin in writeback_sb_inodes() because the wb->list_lock is held, but we could easily plug at a higher level before taking that lock, and unplug after releasing it. This does that. Chris will run performance numbers, just to verify that this approach is comparable to the alternative (we could just drop and re-take the lock around the blk_finish_plug() rather than these two commits. I'd have preferred waiting for actual performance numbers before picking one approach over the other, but I don't want to release rc1 with the known "sleeping function called from invalid context" issue, so I'll pick this cleanup version for now. But if the numbers show that we really want to plug just at the writeback_sb_inodes() level, and we should just play ugly games with the spinlock, we'll switch to that. Cc: Chris Mason <clm@fb.com> Cc: Josef Bacik <jbacik@fb.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Neil Brown <neilb@suse.de> Cc: Jan Kara <jack@suse.cz> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | Revert "writeback: plug writeback at a high level"Linus Torvalds2015-09-111-3/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit d353d7587d02116b9732d5c06615aed75a4d3a47. Doing the block layer plug/unplug inside writeback_sb_inodes() is broken, because that function is actually called with a spinlock held: wb->list_lock, as pointed out by Chris Mason. Chris suggested just dropping and re-taking the spinlock around the blk_finish_plug() call (the plgging itself can happen under the spinlock), and that would technically work, but is just disgusting. We do something fairly similar - but not quite as disgusting because we at least have a better reason for it - in writeback_single_inode(), so it's not like the caller can depend on the lock being held over the call, but in this case there just isn't any good reason for that "release and re-take the lock" pattern. [ In general, we should really strive to avoid the "release and retake" pattern for locks, because in the general case it can easily cause subtle bugs when the caller caches any state around the call that might be invalidated by dropping the lock even just temporarily. ] But in this case, the plugging should be easy to just move up to the callers before the spinlock is taken, which should even improve the effectiveness of the plug. So there is really no good reason to play games with locking here. I'll send off a test-patch so that Dave Chinner can verify that that plug movement works. In the meantime this just reverts the problematic commit and adds a comment to the function so that we hopefully don't make this mistake again. Reported-by: Chris Mason <clm@fb.com> Cc: Josef Bacik <jbacik@fb.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Neil Brown <neilb@suse.de> Cc: Jan Kara <jack@suse.cz> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | thermal: fix intel PCH thermal driver mismergeLinus Torvalds2015-09-121-7/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I didn't notice this when merging the thermal code from Zhang, but his merge (commit 5a924a07f882: "Merge branches 'thermal-core' and 'thermal-intel' of .git into next") of the thermal-core and thermal-intel branches was wrong. In thermal-core, commit 17e8351a7739 ("thermal: consistently use int for temperatures") converted the thermal layer to use "int" for temperatures. But in parallel, in the thermal-intel branch commit d0a12625d2ff ("thermal: Add Intel PCH thermal driver") added support for the intel PCH thermal sensor using the old interfaces that used "unsigned long" pointers. This resulted in warnings like this: drivers/thermal/intel_pch_thermal.c:184:14: warning: initialization from incompatible pointer type [-Wincompatible-pointer-types] .get_temp = pch_thermal_get_temp, ^ drivers/thermal/intel_pch_thermal.c:184:14: note: (near initialization for ‘tzd_ops.get_temp’) drivers/thermal/intel_pch_thermal.c:186:19: warning: initialization from incompatible pointer type [-Wincompatible-pointer-types] .get_trip_temp = pch_get_trip_temp, ^ drivers/thermal/intel_pch_thermal.c:186:19: note: (near initialization for ‘tzd_ops.get_trip_temp’) This fixes it. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | Merge branch 'akpm' (patches from Andrew)Linus Torvalds2015-09-1222-54/+336
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge fourth patch-bomb from Andrew Morton: - sys_membarier syscall - seq_file interface changes - a few misc fixups * emailed patches from Andrew Morton <akpm@linux-foundation.org>: revert "ocfs2/dlm: use list_for_each_entry instead of list_for_each" mm/early_ioremap: add explicit #include of asm/early_ioremap.h fs/seq_file: convert int seq_vprint/seq_printf/etc... returns to void selftests: enhance membarrier syscall test selftests: add membarrier syscall test sys_membarrier(): system-wide memory barrier (generic, x86) MODSIGN: fix a compilation warning in extract-cert
| * | | revert "ocfs2/dlm: use list_for_each_entry instead of list_for_each"Andrew Morton2015-09-121-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Revert commit f83c7b5e9fd6 ("ocfs2/dlm: use list_for_each_entry instead of list_for_each"). list_for_each_entry() will dereference its `pos' argument, which can be NULL in dlm_process_recovery_data(). Reported-by: Julia Lawall <julia.lawall@lip6.fr> Reported-by: Fengguang Wu <fengguang.wu@gmail.com> Cc: Joseph Qi <joseph.qi@huawei.com> Cc: Mark Fasheh <mfasheh@suse.de> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | mm/early_ioremap: add explicit #include of asm/early_ioremap.hArd Biesheuvel2015-09-121-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 6b0f68e32ea8 ("mm: add utility for early copy from unmapped ram") introduces a function copy_from_early_mem() into mm/early_ioremap.c which itself calls early_memremap()/early_memunmap(). However, since early_memunmap() has not been declared yet at this point in the .c file, nor by any explicitly included header files, we are depending on a transitive include of asm/early_ioremap.h to declare it, which is fragile. So instead, include this header explicitly. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Mark Salter <msalter@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | fs/seq_file: convert int seq_vprint/seq_printf/etc... returns to voidJoe Perches2015-09-124-50/+45
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The seq_<foo> function return values were frequently misused. See: commit 1f33c41c03da ("seq_file: Rename seq_overflow() to seq_has_overflowed() and make public") All uses of these return values have been removed, so convert the return types to void. Miscellanea: o Move seq_put_decimal_<type> and seq_escape prototypes closer the other seq_vprintf prototypes o Reorder seq_putc and seq_puts to return early on overflow o Add argument names to seq_vprintf and seq_printf o Update the seq_escape kernel-doc o Convert a couple of leading spaces to tabs in seq_escape Signed-off-by: Joe Perches <joe@perches.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Mark Brown <broonie@kernel.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Joerg Roedel <jroedel@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | selftests: enhance membarrier syscall testMathieu Desnoyers2015-09-121-25/+75
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Update the membarrier syscall self-test to match the membarrier interface. Extend coverage of the interface. Consider ENOSYS as a "SKIP" test, since it is a valid configuration, but does not allow testing the system call. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Pranith Kumar <bobby.prani@gmail.com> Cc: Shuah Khan <shuahkh@osg.samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | selftests: add membarrier syscall testPranith Kumar2015-09-124-0/+84
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a self test for the membarrier system call. Signed-off-by: Pranith Kumar <bobby.prani@gmail.com> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Shuah Khan <shuahkh@osg.samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | sys_membarrier(): system-wide memory barrier (generic, x86)Mathieu Desnoyers2015-09-1211-1/+151
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Here is an implementation of a new system call, sys_membarrier(), which executes a memory barrier on all threads running on the system. It is implemented by calling synchronize_sched(). It can be used to distribute the cost of user-space memory barriers asymmetrically by transforming pairs of memory barriers into pairs consisting of sys_membarrier() and a compiler barrier. For synchronization primitives that distinguish between read-side and write-side (e.g. userspace RCU [1], rwlocks), the read-side can be accelerated significantly by moving the bulk of the memory barrier overhead to the write-side. The existing applications of which I am aware that would be improved by this system call are as follows: * Through Userspace RCU library (http://urcu.so) - DNS server (Knot DNS) https://www.knot-dns.cz/ - Network sniffer (http://netsniff-ng.org/) - Distributed object storage (https://sheepdog.github.io/sheepdog/) - User-space tracing (http://lttng.org) - Network storage system (https://www.gluster.org/) - Virtual routers (https://events.linuxfoundation.org/sites/events/files/slides/DPDK_RCU_0MQ.pdf) - Financial software (https://lkml.org/lkml/2015/3/23/189) Those projects use RCU in userspace to increase read-side speed and scalability compared to locking. Especially in the case of RCU used by libraries, sys_membarrier can speed up the read-side by moving the bulk of the memory barrier cost to synchronize_rcu(). * Direct users of sys_membarrier - core dotnet garbage collector (https://github.com/dotnet/coreclr/issues/198) Microsoft core dotnet GC developers are planning to use the mprotect() side-effect of issuing memory barriers through IPIs as a way to implement Windows FlushProcessWriteBuffers() on Linux. They are referring to sys_membarrier in their github thread, specifically stating that sys_membarrier() is what they are looking for. To explain the benefit of this scheme, let's introduce two example threads: Thread A (non-frequent, e.g. executing liburcu synchronize_rcu()) Thread B (frequent, e.g. executing liburcu rcu_read_lock()/rcu_read_unlock()) In a scheme where all smp_mb() in thread A are ordering memory accesses with respect to smp_mb() present in Thread B, we can change each smp_mb() within Thread A into calls to sys_membarrier() and each smp_mb() within Thread B into compiler barriers "barrier()". Before the change, we had, for each smp_mb() pairs: Thread A Thread B previous mem accesses previous mem accesses smp_mb() smp_mb() following mem accesses following mem accesses After the change, these pairs become: Thread A Thread B prev mem accesses prev mem accesses sys_membarrier() barrier() follow mem accesses follow mem accesses As we can see, there are two possible scenarios: either Thread B memory accesses do not happen concurrently with Thread A accesses (1), or they do (2). 1) Non-concurrent Thread A vs Thread B accesses: Thread A Thread B prev mem accesses sys_membarrier() follow mem accesses prev mem accesses barrier() follow mem accesses In this case, thread B accesses will be weakly ordered. This is OK, because at that point, thread A is not particularly interested in ordering them with respect to its own accesses. 2) Concurrent Thread A vs Thread B accesses Thread A Thread B prev mem accesses prev mem accesses sys_membarrier() barrier() follow mem accesses follow mem accesses In this case, thread B accesses, which are ensured to be in program order thanks to the compiler barrier, will be "upgraded" to full smp_mb() by synchronize_sched(). * Benchmarks On Intel Xeon E5405 (8 cores) (one thread is calling sys_membarrier, the other 7 threads are busy looping) 1000 non-expedited sys_membarrier calls in 33s =3D 33 milliseconds/call. * User-space user of this system call: Userspace RCU library Both the signal-based and the sys_membarrier userspace RCU schemes permit us to remove the memory barrier from the userspace RCU rcu_read_lock() and rcu_read_unlock() primitives, thus significantly accelerating them. These memory barriers are replaced by compiler barriers on the read-side, and all matching memory barriers on the write-side are turned into an invocation of a memory barrier on all active threads in the process. By letting the kernel perform this synchronization rather than dumbly sending a signal to every process threads (as we currently do), we diminish the number of unnecessary wake ups and only issue the memory barriers on active threads. Non-running threads do not need to execute such barrier anyway, because these are implied by the scheduler context switches. Results in liburcu: Operations in 10s, 6 readers, 2 writers: memory barriers in reader: 1701557485 reads, 2202847 writes signal-based scheme: 9830061167 reads, 6700 writes sys_membarrier: 9952759104 reads, 425 writes sys_membarrier (dyn. check): 7970328887 reads, 425 writes The dynamic sys_membarrier availability check adds some overhead to the read-side compared to the signal-based scheme, but besides that, sys_membarrier slightly outperforms the signal-based scheme. However, this non-expedited sys_membarrier implementation has a much slower grace period than signal and memory barrier schemes. Besides diminishing the number of wake-ups, one major advantage of the membarrier system call over the signal-based scheme is that it does not need to reserve a signal. This plays much more nicely with libraries, and with processes injected into for tracing purposes, for which we cannot expect that signals will be unused by the application. An expedited version of this system call can be added later on to speed up the grace period. Its implementation will likely depend on reading the cpu_curr()->mm without holding each CPU's rq lock. This patch adds the system call to x86 and to asm-generic. [1] http://urcu.so membarrier(2) man page: MEMBARRIER(2) Linux Programmer's Manual MEMBARRIER(2) NAME membarrier - issue memory barriers on a set of threads SYNOPSIS #include <linux/membarrier.h> int membarrier(int cmd, int flags); DESCRIPTION The cmd argument is one of the following: MEMBARRIER_CMD_QUERY Query the set of supported commands. It returns a bitmask of supported commands. MEMBARRIER_CMD_SHARED Execute a memory barrier on all threads running on the system. Upon return from system call, the caller thread is ensured that all running threads have passed through a state where all memory accesses to user-space addresses match program order between entry to and return from the system call (non-running threads are de facto in such a state). This covers threads from all pro=E2=80=90 cesses running on the system. This command returns 0. The flags argument needs to be 0. For future extensions. All memory accesses performed in program order from each targeted thread is guaranteed to be ordered with respect to sys_membarrier(). If we use the semantic "barrier()" to represent a compiler barrier forcing memory accesses to be performed in program order across the barrier, and smp_mb() to represent explicit memory barriers forcing full memory ordering across the barrier, we have the following ordering table for each pair of barrier(), sys_membarrier() and smp_mb(): The pair ordering is detailed as (O: ordered, X: not ordered): barrier() smp_mb() sys_membarrier() barrier() X X O smp_mb() X O O sys_membarrier() O O O RETURN VALUE On success, these system calls return zero. On error, -1 is returned, and errno is set appropriately. For a given command, with flags argument set to 0, this system call is guaranteed to always return the same value until reboot. ERRORS ENOSYS System call is not implemented. EINVAL Invalid arguments. Linux 2015-04-15 MEMBARRIER(2) Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Nicholas Miell <nmiell@comcast.net> Cc: Ingo Molnar <mingo@redhat.com> Cc: Alan Cox <gnomes@lxorguk.ukuu.org.uk> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: David Howells <dhowells@redhat.com> Cc: Pranith Kumar <bobby.prani@gmail.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Shuah Khan <shuahkh@osg.samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | | MODSIGN: fix a compilation warning in extract-certDavid Howells2015-09-121-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix the following warning when compiling extract-cert: scripts/extract-cert.c: In function `write_cert': scripts/extract-cert.c:89:2: warning: format not a string literal and no format arguments [-Wformat-security] ERR(!i2d_X509_bio(wb, x509), cert_dst); ^ whereby the ERR() macro is taking cert_dst as the format string. "%s" should be used as the format string as the path could contain special characters. Signed-off-by: David Howells <dhowells@redhat.com> Reported-by: Jim Davis <jim.epost@gmail.com> Acked-by : David Woodhouse <david.woodhouse@intel.com> Cc: James Morris <jmorris@namei.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | | ARCv2: [axs103_smp] Reduce clk for SMP FPGA configsVineet Gupta2015-09-121-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Newer bitfiles needs the reduced clk even for SMP builds Cc: <stable@vger.kernel.org> #4.2 Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | | Merge tag 'ntb-4.3' of git://github.com/jonmason/ntbLinus Torvalds2015-09-127-47/+210
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull NTB fixes from Jon Mason: "NTB bug and documentation fixes, new device IDs, performance improvements, and adding a mailing list to MAINTAINERS for NTB" * tag 'ntb-4.3' of git://github.com/jonmason/ntb: NTB: Fix range check on memory window index NTB: Improve index handling in B2B MW workaround NTB: Fix documentation for ntb_peer_db_clear. NTB: Fix documentation for ntb_link_is_up NTB: Use unique DMA channels for TX and RX NTB: Remove dma_sync_wait from ntb_async_rx NTB: Clean up QP stats info NTB: Make the transport list in order of discovery NTB: Add PCI Device IDs for Broadwell Xeon NTB: Add flow control to the ntb_netdev NTB: Add list to MAINTAINERS
| * | | | NTB: Fix range check on memory window indexAllen Hubbe2015-09-071-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The range check must exclude the upper bound. Signed-off-by: Allen Hubbe <Allen.Hubbe@emc.com> Signed-off-by: Jon Mason <jdmason@kudzu.us>
| * | | | NTB: Improve index handling in B2B MW workaroundAllen Hubbe2015-09-071-6/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Check that b2b_mw_idx is in range of the number of memory windows when initializing the device. The workaround is considered to be in effect only if the device b2b_idx is exactly UINT_MAX, instead of any index past the last memory window. Only print B2B MW workaround information in debugfs if the workaround is in effect. Signed-off-by: Allen Hubbe <Allen.Hubbe@emc.com> Signed-off-by: Jon Mason <jdmason@kudzu.us>
| * | | | NTB: Fix documentation for ntb_peer_db_clear.Allen Hubbe2015-09-071-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The documentation should say "peer" not "local" when referring to the peer doorbell register. Reported-by: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Allen Hubbe <Allen.Hubbe@emc.com> Signed-off-by: Jon Mason <jdmason@kudzu.us>
| * | | | NTB: Fix documentation for ntb_link_is_upAllen Hubbe2015-09-071-4/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There was a copy and paste error in the documentation for ntb_link_is_up. The long description was mistakenly copied from ntb_link_set_trans. This adds the appropriate long description for ntb_link_is_up. Reported-by: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Allen Hubbe <Allen.Hubbe@emc.com> Signed-off-by: Jon Mason <jdmason@kudzu.us>
| * | | | NTB: Use unique DMA channels for TX and RXDave Jiang2015-09-071-19/+58
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Allocate two DMA channels, one for TX operation and one for RX operation, instead of having one DMA channel for everything. This provides slightly better performance, and also will make error handling cleaner later on. Signed-off-by: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Jon Mason <jdmason@kudzu.us>
| * | | | NTB: Remove dma_sync_wait from ntb_async_rxAllen Hubbe2015-09-071-9/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The dma_sync_wait can hurt the performance of workloads mixed with both large and small frames. Large frames will be copied using the dma engine. Small frames will be copied by the cpu. The dma_sync_wait prevents the cpu and dma engine copying in parallel. In the period where the cpu is copying, the dma engine is stopped. The dma engine is not doing any useful work to copy large frames during that time, and the additional time to restart the dma engine for the next large frame. This will decrease the throughput for the portion of a workload with large frames. In the period where the dma engine is copying, the cpu is held up waiting for dma to complete. The small frames processing will be delayed until the dma is complete. The RX frames are completed in-order, and the processing of small frames takes very little time, so dma_sync_wait may have an insignificant impact on the respose time of frames. The more significant impact is to the system, because the delay in dma_sync_wait is implemented as busy non-blocking wait. This can prevent the delayed core from doing any useful work, even if it could be processing work for other drivers, unrelated to transport RX processing. After applying the earlier patch to fix out-of-order RX acknoledgement, the dma_sync_wait is no longer necessary. Remove it, so that cpu memcpy will proceed immediately for small frames, in parallel with ongoing dma for large frames. Do not hold up the cpu from doing work while dma is in progress. The prior fix will continue to ensure in-order completion of the RX frames to the upper layer, and in-order delivery of the RX acknoledgement. Signed-off-by: Allen Hubbe <Allen.Hubbe@emc.com> Signed-off-by: Jon Mason <jdmason@kudzu.us>
| * | | | NTB: Clean up QP stats infoDave Jiang2015-09-071-9/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make QP stats info more readable for debugging purposes. Also add an entry to indicate whether DMA is being used. Signed-off-by: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Jon Mason <jdmason@kudzu.us>
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-25 23:35:18 +0100