diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2008-12-30 17:31:25 -0800 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-12-30 17:31:25 -0800 |
commit | 526ea064f953fc5ad2fb905b537f490b9374a0f0 (patch) | |
tree | c4ff0cb65ce6442863c7c342f641a41f0995329a /drivers | |
parent | db5e53fbf0abf5cadc83be57032242e5e7c6c394 (diff) | |
parent | d69d59f49763e6bd047c591c6c1f84c8e13da931 (diff) |
Merge branch 'oprofile-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'oprofile-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
oprofile: select RING_BUFFER
ring_buffer: adding EXPORT_SYMBOLs
oprofile: fix lost sample counter
oprofile: remove nr_available_slots()
oprofile: port to the new ring_buffer
ring_buffer: add remaining cpu functions to ring_buffer.h
oprofile: moving cpu_buffer_reset() to cpu_buffer.h
oprofile: adding cpu_buffer_entries()
oprofile: adding cpu_buffer_write_commit()
oprofile: adding cpu buffer r/w access functions
ftrace: remove unused function arg in trace_iterator_increment()
ring_buffer: update description for ring_buffer_alloc()
oprofile: set values to default when creating oprofilefs
oprofile: implement switch/case in buffer_sync.c
x86/oprofile: cleanup IBS init/exit functions in op_model_amd.c
x86/oprofile: reordering IBS code in op_model_amd.c
oprofile: fix typo
oprofile: whitspace changes only
oprofile: update comment for oprofile_add_sample()
oprofile: comment cleanup
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/oprofile/buffer_sync.c | 117 | ||||
-rw-r--r-- | drivers/oprofile/cpu_buffer.c | 197 | ||||
-rw-r--r-- | drivers/oprofile/cpu_buffer.h | 69 | ||||
-rw-r--r-- | drivers/oprofile/oprofile_files.c | 15 |
4 files changed, 218 insertions, 180 deletions
diff --git a/drivers/oprofile/buffer_sync.c b/drivers/oprofile/buffer_sync.c index b55cd23ffdef..737bd9484822 100644 --- a/drivers/oprofile/buffer_sync.c +++ b/drivers/oprofile/buffer_sync.c @@ -268,18 +268,6 @@ lookup_dcookie(struct mm_struct *mm, unsigned long addr, off_t *offset) return cookie; } -static void increment_tail(struct oprofile_cpu_buffer *b) -{ - unsigned long new_tail = b->tail_pos + 1; - - rmb(); /* be sure fifo pointers are synchromized */ - - if (new_tail < b->buffer_size) - b->tail_pos = new_tail; - else - b->tail_pos = 0; -} - static unsigned long last_cookie = INVALID_COOKIE; static void add_cpu_switch(int i) @@ -331,28 +319,25 @@ static void add_trace_begin(void) #define IBS_FETCH_CODE_SIZE 2 #define IBS_OP_CODE_SIZE 5 -#define IBS_EIP(offset) \ - (((struct op_sample *)&cpu_buf->buffer[(offset)])->eip) -#define IBS_EVENT(offset) \ - (((struct op_sample *)&cpu_buf->buffer[(offset)])->event) /* * Add IBS fetch and op entries to event buffer */ -static void add_ibs_begin(struct oprofile_cpu_buffer *cpu_buf, int code, - struct mm_struct *mm) +static void add_ibs_begin(int cpu, int code, struct mm_struct *mm) { unsigned long rip; int i, count; unsigned long ibs_cookie = 0; off_t offset; + struct op_sample *sample; - increment_tail(cpu_buf); /* move to RIP entry */ - - rip = IBS_EIP(cpu_buf->tail_pos); + sample = cpu_buffer_read_entry(cpu); + if (!sample) + goto Error; + rip = sample->eip; #ifdef __LP64__ - rip += IBS_EVENT(cpu_buf->tail_pos) << 32; + rip += sample->event << 32; #endif if (mm) { @@ -376,8 +361,8 @@ static void add_ibs_begin(struct oprofile_cpu_buffer *cpu_buf, int code, add_event_entry(offset); /* Offset from Dcookie */ /* we send the Dcookie offset, but send the raw Linear Add also*/ - add_event_entry(IBS_EIP(cpu_buf->tail_pos)); - add_event_entry(IBS_EVENT(cpu_buf->tail_pos)); + add_event_entry(sample->eip); + add_event_entry(sample->event); if (code == IBS_FETCH_CODE) count = IBS_FETCH_CODE_SIZE; /*IBS FETCH is 2 int64s*/ @@ -385,10 +370,17 @@ static void add_ibs_begin(struct oprofile_cpu_buffer *cpu_buf, int code, count = IBS_OP_CODE_SIZE; /*IBS OP is 5 int64s*/ for (i = 0; i < count; i++) { - increment_tail(cpu_buf); - add_event_entry(IBS_EIP(cpu_buf->tail_pos)); - add_event_entry(IBS_EVENT(cpu_buf->tail_pos)); + sample = cpu_buffer_read_entry(cpu); + if (!sample) + goto Error; + add_event_entry(sample->eip); + add_event_entry(sample->event); } + + return; + +Error: + return; } #endif @@ -466,33 +458,6 @@ static inline int is_code(unsigned long val) } -/* "acquire" as many cpu buffer slots as we can */ -static unsigned long get_slots(struct oprofile_cpu_buffer *b) -{ - unsigned long head = b->head_pos; - unsigned long tail = b->tail_pos; - - /* - * Subtle. This resets the persistent last_task - * and in_kernel values used for switching notes. - * BUT, there is a small window between reading - * head_pos, and this call, that means samples - * can appear at the new head position, but not - * be prefixed with the notes for switching - * kernel mode or a task switch. This small hole - * can lead to mis-attribution or samples where - * we don't know if it's in the kernel or not, - * at the start of an event buffer. - */ - cpu_buffer_reset(b); - - if (head >= tail) - return head - tail; - - return head + (b->buffer_size - tail); -} - - /* Move tasks along towards death. Any tasks on dead_tasks * will definitely have no remaining references in any * CPU buffers at this point, because we use two lists, @@ -559,61 +524,61 @@ typedef enum { */ void sync_buffer(int cpu) { - struct oprofile_cpu_buffer *cpu_buf = &per_cpu(cpu_buffer, cpu); struct mm_struct *mm = NULL; + struct mm_struct *oldmm; struct task_struct *new; unsigned long cookie = 0; int in_kernel = 1; sync_buffer_state state = sb_buffer_start; -#ifndef CONFIG_OPROFILE_IBS unsigned int i; unsigned long available; -#endif mutex_lock(&buffer_mutex); add_cpu_switch(cpu); - /* Remember, only we can modify tail_pos */ - -#ifndef CONFIG_OPROFILE_IBS - available = get_slots(cpu_buf); + cpu_buffer_reset(cpu); + available = cpu_buffer_entries(cpu); for (i = 0; i < available; ++i) { -#else - while (get_slots(cpu_buf)) { -#endif - struct op_sample *s = &cpu_buf->buffer[cpu_buf->tail_pos]; + struct op_sample *s = cpu_buffer_read_entry(cpu); + if (!s) + break; if (is_code(s->eip)) { - if (s->event <= CPU_IS_KERNEL) { + switch (s->event) { + case 0: + case CPU_IS_KERNEL: /* kernel/userspace switch */ in_kernel = s->event; if (state == sb_buffer_start) state = sb_sample_start; add_kernel_ctx_switch(s->event); - } else if (s->event == CPU_TRACE_BEGIN) { + break; + case CPU_TRACE_BEGIN: state = sb_bt_start; add_trace_begin(); + break; #ifdef CONFIG_OPROFILE_IBS - } else if (s->event == IBS_FETCH_BEGIN) { + case IBS_FETCH_BEGIN: state = sb_bt_start; - add_ibs_begin(cpu_buf, IBS_FETCH_CODE, mm); - } else if (s->event == IBS_OP_BEGIN) { + add_ibs_begin(cpu, IBS_FETCH_CODE, mm); + break; + case IBS_OP_BEGIN: state = sb_bt_start; - add_ibs_begin(cpu_buf, IBS_OP_CODE, mm); + add_ibs_begin(cpu, IBS_OP_CODE, mm); + break; #endif - } else { - struct mm_struct *oldmm = mm; - + default: /* userspace context switch */ + oldmm = mm; new = (struct task_struct *)s->event; - release_mm(oldmm); mm = take_tasks_mm(new); if (mm != oldmm) cookie = get_exec_dcookie(mm); add_user_ctx_switch(new, cookie); + break; } } else if (state >= sb_bt_start && !add_sample(mm, s, in_kernel)) { @@ -622,8 +587,6 @@ void sync_buffer(int cpu) atomic_inc(&oprofile_stats.bt_lost_no_mapping); } } - - increment_tail(cpu_buf); } release_mm(mm); diff --git a/drivers/oprofile/cpu_buffer.c b/drivers/oprofile/cpu_buffer.c index 01d38e78cde1..61090969158f 100644 --- a/drivers/oprofile/cpu_buffer.c +++ b/drivers/oprofile/cpu_buffer.c @@ -28,6 +28,25 @@ #include "buffer_sync.h" #include "oprof.h" +#define OP_BUFFER_FLAGS 0 + +/* + * Read and write access is using spin locking. Thus, writing to the + * buffer by NMI handler (x86) could occur also during critical + * sections when reading the buffer. To avoid this, there are 2 + * buffers for independent read and write access. Read access is in + * process context only, write access only in the NMI handler. If the + * read buffer runs empty, both buffers are swapped atomically. There + * is potentially a small window during swapping where the buffers are + * disabled and samples could be lost. + * + * Using 2 buffers is a little bit overhead, but the solution is clear + * and does not require changes in the ring buffer implementation. It + * can be changed to a single buffer solution when the ring buffer + * access is implemented as non-locking atomic code. + */ +struct ring_buffer *op_ring_buffer_read; +struct ring_buffer *op_ring_buffer_write; DEFINE_PER_CPU(struct oprofile_cpu_buffer, cpu_buffer); static void wq_sync_buffer(struct work_struct *work); @@ -37,12 +56,12 @@ static int work_enabled; void free_cpu_buffers(void) { - int i; - - for_each_possible_cpu(i) { - vfree(per_cpu(cpu_buffer, i).buffer); - per_cpu(cpu_buffer, i).buffer = NULL; - } + if (op_ring_buffer_read) + ring_buffer_free(op_ring_buffer_read); + op_ring_buffer_read = NULL; + if (op_ring_buffer_write) + ring_buffer_free(op_ring_buffer_write); + op_ring_buffer_write = NULL; } unsigned long oprofile_get_cpu_buffer_size(void) @@ -64,14 +83,16 @@ int alloc_cpu_buffers(void) unsigned long buffer_size = fs_cpu_buffer_size; + op_ring_buffer_read = ring_buffer_alloc(buffer_size, OP_BUFFER_FLAGS); + if (!op_ring_buffer_read) + goto fail; + op_ring_buffer_write = ring_buffer_alloc(buffer_size, OP_BUFFER_FLAGS); + if (!op_ring_buffer_write) + goto fail; + for_each_possible_cpu(i) { struct oprofile_cpu_buffer *b = &per_cpu(cpu_buffer, i); - b->buffer = vmalloc_node(sizeof(struct op_sample) * buffer_size, - cpu_to_node(i)); - if (!b->buffer) - goto fail; - b->last_task = NULL; b->last_is_kernel = -1; b->tracing = 0; @@ -124,57 +145,31 @@ void end_cpu_work(void) flush_scheduled_work(); } -/* Resets the cpu buffer to a sane state. */ -void cpu_buffer_reset(struct oprofile_cpu_buffer *cpu_buf) -{ - /* reset these to invalid values; the next sample - * collected will populate the buffer with proper - * values to initialize the buffer - */ - cpu_buf->last_is_kernel = -1; - cpu_buf->last_task = NULL; -} - -/* compute number of available slots in cpu_buffer queue */ -static unsigned long nr_available_slots(struct oprofile_cpu_buffer const *b) +static inline int +add_sample(struct oprofile_cpu_buffer *cpu_buf, + unsigned long pc, unsigned long event) { - unsigned long head = b->head_pos; - unsigned long tail = b->tail_pos; + struct op_entry entry; + int ret; - if (tail > head) - return (tail - head) - 1; + ret = cpu_buffer_write_entry(&entry); + if (ret) + return ret; - return tail + (b->buffer_size - head) - 1; -} + entry.sample->eip = pc; + entry.sample->event = event; -static void increment_head(struct oprofile_cpu_buffer *b) -{ - unsigned long new_head = b->head_pos + 1; - - /* Ensure anything written to the slot before we - * increment is visible */ - wmb(); - - if (new_head < b->buffer_size) - b->head_pos = new_head; - else - b->head_pos = 0; -} + ret = cpu_buffer_write_commit(&entry); + if (ret) + return ret; -static inline void -add_sample(struct oprofile_cpu_buffer *cpu_buf, - unsigned long pc, unsigned long event) -{ - struct op_sample *entry = &cpu_buf->buffer[cpu_buf->head_pos]; - entry->eip = pc; - entry->event = event; - increment_head(cpu_buf); + return 0; } -static inline void +static inline int add_code(struct oprofile_cpu_buffer *buffer, unsigned long value) { - add_sample(buffer, ESCAPE_CODE, value); + return add_sample(buffer, ESCAPE_CODE, value); } /* This must be safe from any context. It's safe writing here @@ -198,11 +193,6 @@ static int log_sample(struct oprofile_cpu_buffer *cpu_buf, unsigned long pc, return 0; } - if (nr_available_slots(cpu_buf) < 3) { - cpu_buf->sample_lost_overflow++; - return 0; - } - is_kernel = !!is_kernel; task = current; @@ -210,26 +200,29 @@ static int log_sample(struct oprofile_cpu_buffer *cpu_buf, unsigned long pc, /* notice a switch from user->kernel or vice versa */ if (cpu_buf->last_is_kernel != is_kernel) { cpu_buf->last_is_kernel = is_kernel; - add_code(cpu_buf, is_kernel); + if (add_code(cpu_buf, is_kernel)) + goto fail; } /* notice a task switch */ if (cpu_buf->last_task != task) { cpu_buf->last_task = task; - add_code(cpu_buf, (unsigned long)task); + if (add_code(cpu_buf, (unsigned long)task)) + goto fail; } - add_sample(cpu_buf, pc, event); + if (add_sample(cpu_buf, pc, event)) + goto fail; + return 1; + +fail: + cpu_buf->sample_lost_overflow++; + return 0; } static int oprofile_begin_trace(struct oprofile_cpu_buffer *cpu_buf) { - if (nr_available_slots(cpu_buf) < 4) { - cpu_buf->sample_lost_overflow++; - return 0; - } - add_code(cpu_buf, CPU_TRACE_BEGIN); cpu_buf->tracing = 1; return 1; @@ -253,8 +246,10 @@ void oprofile_add_ext_sample(unsigned long pc, struct pt_regs * const regs, if (!oprofile_begin_trace(cpu_buf)) return; - /* if log_sample() fail we can't backtrace since we lost the source - * of this event */ + /* + * if log_sample() fail we can't backtrace since we lost the + * source of this event + */ if (log_sample(cpu_buf, pc, is_kernel, event)) oprofile_ops.backtrace(regs, backtrace_depth); oprofile_end_trace(cpu_buf); @@ -272,49 +267,55 @@ void oprofile_add_sample(struct pt_regs * const regs, unsigned long event) #define MAX_IBS_SAMPLE_SIZE 14 -void oprofile_add_ibs_sample(struct pt_regs *const regs, - unsigned int *const ibs_sample, int ibs_code) +void oprofile_add_ibs_sample(struct pt_regs * const regs, + unsigned int * const ibs_sample, int ibs_code) { int is_kernel = !user_mode(regs); struct oprofile_cpu_buffer *cpu_buf = &__get_cpu_var(cpu_buffer); struct task_struct *task; + int fail = 0; cpu_buf->sample_received++; - if (nr_available_slots(cpu_buf) < MAX_IBS_SAMPLE_SIZE) { - /* we can't backtrace since we lost the source of this event */ - cpu_buf->sample_lost_overflow++; - return; - } - /* notice a switch from user->kernel or vice versa */ if (cpu_buf->last_is_kernel != is_kernel) { + if (add_code(cpu_buf, is_kernel)) + goto fail; cpu_buf->last_is_kernel = is_kernel; - add_code(cpu_buf, is_kernel); } /* notice a task switch */ if (!is_kernel) { task = current; if (cpu_buf->last_task != task) { + if (add_code(cpu_buf, (unsigned long)task)) + goto fail; cpu_buf->last_task = task; - add_code(cpu_buf, (unsigned long)task); } } - add_code(cpu_buf, ibs_code); - add_sample(cpu_buf, ibs_sample[0], ibs_sample[1]); - add_sample(cpu_buf, ibs_sample[2], ibs_sample[3]); - add_sample(cpu_buf, ibs_sample[4], ibs_sample[5]); + fail = fail || add_code(cpu_buf, ibs_code); + fail = fail || add_sample(cpu_buf, ibs_sample[0], ibs_sample[1]); + fail = fail || add_sample(cpu_buf, ibs_sample[2], ibs_sample[3]); + fail = fail || add_sample(cpu_buf, ibs_sample[4], ibs_sample[5]); if (ibs_code == IBS_OP_BEGIN) { - add_sample(cpu_buf, ibs_sample[6], ibs_sample[7]); - add_sample(cpu_buf, ibs_sample[8], ibs_sample[9]); - add_sample(cpu_buf, ibs_sample[10], ibs_sample[11]); + fail = fail || add_sample(cpu_buf, ibs_sample[6], ibs_sample[7]); + fail = fail || add_sample(cpu_buf, ibs_sample[8], ibs_sample[9]); + fail = fail || add_sample(cpu_buf, ibs_sample[10], ibs_sample[11]); } + if (fail) + goto fail; + if (backtrace_depth) oprofile_ops.backtrace(regs, backtrace_depth); + + return; + +fail: + cpu_buf->sample_lost_overflow++; + return; } #endif @@ -332,21 +333,21 @@ void oprofile_add_trace(unsigned long pc) if (!cpu_buf->tracing) return; - if (nr_available_slots(cpu_buf) < 1) { - cpu_buf->tracing = 0; - cpu_buf->sample_lost_overflow++; - return; - } + /* + * broken frame can give an eip with the same value as an + * escape code, abort the trace if we get it + */ + if (pc == ESCAPE_CODE) + goto fail; - /* broken frame can give an eip with the same value as an escape code, - * abort the trace if we get it */ - if (pc == ESCAPE_CODE) { - cpu_buf->tracing = 0; - cpu_buf->backtrace_aborted++; - return; - } + if (add_sample(cpu_buf, pc, 0)) + goto fail; - add_sample(cpu_buf, pc, 0); + return; +fail: + cpu_buf->tracing = 0; + cpu_buf->backtrace_aborted++; + return; } /* diff --git a/drivers/oprofile/cpu_buffer.h b/drivers/oprofile/cpu_buffer.h index d3cc26264db5..aacb0f0bc566 100644 --- a/drivers/oprofile/cpu_buffer.h +++ b/drivers/oprofile/cpu_buffer.h @@ -15,6 +15,7 @@ #include <linux/workqueue.h> #include <linux/cache.h> #include <linux/sched.h> +#include <linux/ring_buffer.h> struct task_struct; @@ -32,6 +33,12 @@ struct op_sample { unsigned long event; }; +struct op_entry { + struct ring_buffer_event *event; + struct op_sample *sample; + unsigned long irq_flags; +}; + struct oprofile_cpu_buffer { volatile unsigned long head_pos; volatile unsigned long tail_pos; @@ -39,7 +46,6 @@ struct oprofile_cpu_buffer { struct task_struct *last_task; int last_is_kernel; int tracing; - struct op_sample *buffer; unsigned long sample_received; unsigned long sample_lost_overflow; unsigned long backtrace_aborted; @@ -48,9 +54,68 @@ struct oprofile_cpu_buffer { struct delayed_work work; }; +extern struct ring_buffer *op_ring_buffer_read; +extern struct ring_buffer *op_ring_buffer_write; DECLARE_PER_CPU(struct oprofile_cpu_buffer, cpu_buffer); -void cpu_buffer_reset(struct oprofile_cpu_buffer *cpu_buf); +/* + * Resets the cpu buffer to a sane state. + * + * reset these to invalid values; the next sample collected will + * populate the buffer with proper values to initialize the buffer + */ +static inline void cpu_buffer_reset(int cpu) +{ + struct oprofile_cpu_buffer *cpu_buf = &per_cpu(cpu_buffer, cpu); + + cpu_buf->last_is_kernel = -1; + cpu_buf->last_task = NULL; +} + +static inline int cpu_buffer_write_entry(struct op_entry *entry) +{ + entry->event = ring_buffer_lock_reserve(op_ring_buffer_write, + sizeof(struct op_sample), + &entry->irq_flags); + if (entry->event) + entry->sample = ring_buffer_event_data(entry->event); + else + entry->sample = NULL; + + if (!entry->sample) + return -ENOMEM; + + return 0; +} + +static inline int cpu_buffer_write_commit(struct op_entry *entry) +{ + return ring_buffer_unlock_commit(op_ring_buffer_write, entry->event, + entry->irq_flags); +} + +static inline struct op_sample *cpu_buffer_read_entry(int cpu) +{ + struct ring_buffer_event *e; + e = ring_buffer_consume(op_ring_buffer_read, cpu, NULL); + if (e) + return ring_buffer_event_data(e); + if (ring_buffer_swap_cpu(op_ring_buffer_read, + op_ring_buffer_write, + cpu)) + return NULL; + e = ring_buffer_consume(op_ring_buffer_read, cpu, NULL); + if (e) + return ring_buffer_event_data(e); + return NULL; +} + +/* "acquire" as many cpu buffer slots as we can */ +static inline unsigned long cpu_buffer_entries(int cpu) +{ + return ring_buffer_entries_cpu(op_ring_buffer_read, cpu) + + ring_buffer_entries_cpu(op_ring_buffer_write, cpu); +} /* transient events for the CPU buffer -> event buffer */ #define CPU_IS_KERNEL 1 diff --git a/drivers/oprofile/oprofile_files.c b/drivers/oprofile/oprofile_files.c index cc106d503ace..d8201998b0b7 100644 --- a/drivers/oprofile/oprofile_files.c +++ b/drivers/oprofile/oprofile_files.c @@ -14,9 +14,13 @@ #include "oprofile_stats.h" #include "oprof.h" -unsigned long fs_buffer_size = 131072; -unsigned long fs_cpu_buffer_size = 8192; -unsigned long fs_buffer_watershed = 32768; /* FIXME: tune */ +#define FS_BUFFER_SIZE_DEFAULT 131072 +#define FS_CPU_BUFFER_SIZE_DEFAULT 8192 +#define FS_BUFFER_WATERSHED_DEFAULT 32768 /* FIXME: tune */ + +unsigned long fs_buffer_size; +unsigned long fs_cpu_buffer_size; +unsigned long fs_buffer_watershed; static ssize_t depth_read(struct file *file, char __user *buf, size_t count, loff_t *offset) { @@ -120,6 +124,11 @@ static const struct file_operations dump_fops = { void oprofile_create_files(struct super_block *sb, struct dentry *root) { + /* reinitialize default values */ + fs_buffer_size = FS_BUFFER_SIZE_DEFAULT; + fs_cpu_buffer_size = FS_CPU_BUFFER_SIZE_DEFAULT; + fs_buffer_watershed = FS_BUFFER_WATERSHED_DEFAULT; + oprofilefs_create_file(sb, root, "enable", &enable_fops); oprofilefs_create_file_perm(sb, root, "dump", &dump_fops, 0666); oprofilefs_create_file(sb, root, "buffer", &event_buffer_fops); |