X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=blobdiff_plain;f=arch%2Fpowerpc%2Fplatforms%2Fpseries%2Fdtl.c;h=c371bc06434bf5f4121db3b4b6d79c7b64073e3c;hp=a00addb559456e6c3ea69658887f630378863ff1;hb=91b745016c12d440386c40fb76ab69c8e08cbc06;hpb=7ebd467551ed6ae200d7835a84bbda0dcadaa511 diff --git a/arch/powerpc/platforms/pseries/dtl.c b/arch/powerpc/platforms/pseries/dtl.c index a00addb55945..c371bc06434b 100644 --- a/arch/powerpc/platforms/pseries/dtl.c +++ b/arch/powerpc/platforms/pseries/dtl.c @@ -23,37 +23,22 @@ #include #include #include +#include #include #include #include #include +#include #include "plpar_wrappers.h" -/* - * Layout of entries in the hypervisor's DTL buffer. Although we don't - * actually access the internals of an entry (we only need to know the size), - * we might as well define it here for reference. - */ -struct dtl_entry { - u8 dispatch_reason; - u8 preempt_reason; - u16 processor_id; - u32 enqueue_to_dispatch_time; - u32 ready_to_enqueue_time; - u32 waiting_to_ready_time; - u64 timebase; - u64 fault_addr; - u64 srr0; - u64 srr1; -}; - struct dtl { struct dtl_entry *buf; struct dentry *file; int cpu; int buf_entries; u64 last_idx; + spinlock_t lock; }; static DEFINE_PER_CPU(struct dtl, cpu_dtl); @@ -72,25 +57,97 @@ static u8 dtl_event_mask = 0x7; static int dtl_buf_entries = (16 * 85); -static int dtl_enable(struct dtl *dtl) +#ifdef CONFIG_VIRT_CPU_ACCOUNTING +struct dtl_ring { + u64 write_index; + struct dtl_entry *write_ptr; + struct dtl_entry *buf; + struct dtl_entry *buf_end; + u8 saved_dtl_mask; +}; + +static DEFINE_PER_CPU(struct dtl_ring, dtl_rings); + +static atomic_t dtl_count; + +/* + * The cpu accounting code controls the DTL ring buffer, and we get + * given entries as they are processed. + */ +static void consume_dtle(struct dtl_entry *dtle, u64 index) { - unsigned long addr; - int ret, hwcpu; + struct dtl_ring *dtlr = &__get_cpu_var(dtl_rings); + struct dtl_entry *wp = dtlr->write_ptr; + struct lppaca *vpa = local_paca->lppaca_ptr; - /* only allow one reader */ - if (dtl->buf) - return -EBUSY; + if (!wp) + return; - /* we need to store the original allocation size for use during read */ - dtl->buf_entries = dtl_buf_entries; + *wp = *dtle; + barrier(); - dtl->buf = kmalloc_node(dtl->buf_entries * sizeof(struct dtl_entry), - GFP_KERNEL, cpu_to_node(dtl->cpu)); - if (!dtl->buf) { - printk(KERN_WARNING "%s: buffer alloc failed for cpu %d\n", - __func__, dtl->cpu); - return -ENOMEM; - } + /* check for hypervisor ring buffer overflow, ignore this entry if so */ + if (index + N_DISPATCH_LOG < vpa->dtl_idx) + return; + + ++wp; + if (wp == dtlr->buf_end) + wp = dtlr->buf; + dtlr->write_ptr = wp; + + /* incrementing write_index makes the new entry visible */ + smp_wmb(); + ++dtlr->write_index; +} + +static int dtl_start(struct dtl *dtl) +{ + struct dtl_ring *dtlr = &per_cpu(dtl_rings, dtl->cpu); + + dtlr->buf = dtl->buf; + dtlr->buf_end = dtl->buf + dtl->buf_entries; + dtlr->write_index = 0; + + /* setting write_ptr enables logging into our buffer */ + smp_wmb(); + dtlr->write_ptr = dtl->buf; + + /* enable event logging */ + dtlr->saved_dtl_mask = lppaca_of(dtl->cpu).dtl_enable_mask; + lppaca_of(dtl->cpu).dtl_enable_mask |= dtl_event_mask; + + dtl_consumer = consume_dtle; + atomic_inc(&dtl_count); + return 0; +} + +static void dtl_stop(struct dtl *dtl) +{ + struct dtl_ring *dtlr = &per_cpu(dtl_rings, dtl->cpu); + + dtlr->write_ptr = NULL; + smp_wmb(); + + dtlr->buf = NULL; + + /* restore dtl_enable_mask */ + lppaca_of(dtl->cpu).dtl_enable_mask = dtlr->saved_dtl_mask; + + if (atomic_dec_and_test(&dtl_count)) + dtl_consumer = NULL; +} + +static u64 dtl_current_index(struct dtl *dtl) +{ + return per_cpu(dtl_rings, dtl->cpu).write_index; +} + +#else /* CONFIG_VIRT_CPU_ACCOUNTING */ + +static int dtl_start(struct dtl *dtl) +{ + unsigned long addr; + int ret, hwcpu; /* Register our dtl buffer with the hypervisor. The HV expects the * buffer size to be passed in the second word of the buffer */ @@ -102,34 +159,82 @@ static int dtl_enable(struct dtl *dtl) if (ret) { printk(KERN_WARNING "%s: DTL registration for cpu %d (hw %d) " "failed with %d\n", __func__, dtl->cpu, hwcpu, ret); - kfree(dtl->buf); return -EIO; } /* set our initial buffer indices */ - dtl->last_idx = lppaca[dtl->cpu].dtl_idx = 0; + lppaca_of(dtl->cpu).dtl_idx = 0; /* ensure that our updates to the lppaca fields have occurred before * we actually enable the logging */ smp_wmb(); /* enable event logging */ - lppaca[dtl->cpu].dtl_enable_mask = dtl_event_mask; + lppaca_of(dtl->cpu).dtl_enable_mask = dtl_event_mask; return 0; } -static void dtl_disable(struct dtl *dtl) +static void dtl_stop(struct dtl *dtl) { int hwcpu = get_hard_smp_processor_id(dtl->cpu); - lppaca[dtl->cpu].dtl_enable_mask = 0x0; + lppaca_of(dtl->cpu).dtl_enable_mask = 0x0; unregister_dtl(hwcpu, __pa(dtl->buf)); +} + +static u64 dtl_current_index(struct dtl *dtl) +{ + return lppaca_of(dtl->cpu).dtl_idx; +} +#endif /* CONFIG_VIRT_CPU_ACCOUNTING */ + +static int dtl_enable(struct dtl *dtl) +{ + long int n_entries; + long int rc; + struct dtl_entry *buf = NULL; + /* only allow one reader */ + if (dtl->buf) + return -EBUSY; + + n_entries = dtl_buf_entries; + buf = kmalloc_node(n_entries * sizeof(struct dtl_entry), + GFP_KERNEL, cpu_to_node(dtl->cpu)); + if (!buf) { + printk(KERN_WARNING "%s: buffer alloc failed for cpu %d\n", + __func__, dtl->cpu); + return -ENOMEM; + } + + spin_lock(&dtl->lock); + rc = -EBUSY; + if (!dtl->buf) { + /* store the original allocation size for use during read */ + dtl->buf_entries = n_entries; + dtl->buf = buf; + dtl->last_idx = 0; + rc = dtl_start(dtl); + if (rc) + dtl->buf = NULL; + } + spin_unlock(&dtl->lock); + + if (rc) + kfree(buf); + return rc; +} + +static void dtl_disable(struct dtl *dtl) +{ + spin_lock(&dtl->lock); + dtl_stop(dtl); kfree(dtl->buf); dtl->buf = NULL; dtl->buf_entries = 0; + spin_unlock(&dtl->lock); } /* file interface */ @@ -157,8 +262,9 @@ static int dtl_file_release(struct inode *inode, struct file *filp) static ssize_t dtl_file_read(struct file *filp, char __user *buf, size_t len, loff_t *pos) { - int rc, cur_idx, last_idx, n_read, n_req, read_size; + long int rc, n_read, n_req, read_size; struct dtl *dtl; + u64 cur_idx, last_idx, i; if ((len % sizeof(struct dtl_entry)) != 0) return -EINVAL; @@ -171,41 +277,48 @@ static ssize_t dtl_file_read(struct file *filp, char __user *buf, size_t len, /* actual number of entries read */ n_read = 0; - cur_idx = lppaca[dtl->cpu].dtl_idx; + spin_lock(&dtl->lock); + + cur_idx = dtl_current_index(dtl); last_idx = dtl->last_idx; - if (cur_idx - last_idx > dtl->buf_entries) { - pr_debug("%s: hv buffer overflow for cpu %d, samples lost\n", - __func__, dtl->cpu); - } + if (last_idx + dtl->buf_entries <= cur_idx) + last_idx = cur_idx - dtl->buf_entries + 1; + + if (last_idx + n_req > cur_idx) + n_req = cur_idx - last_idx; + + if (n_req > 0) + dtl->last_idx = last_idx + n_req; + + spin_unlock(&dtl->lock); + + if (n_req <= 0) + return 0; - cur_idx %= dtl->buf_entries; - last_idx %= dtl->buf_entries; + i = last_idx % dtl->buf_entries; /* read the tail of the buffer if we've wrapped */ - if (last_idx > cur_idx) { - read_size = min(n_req, dtl->buf_entries - last_idx); + if (i + n_req > dtl->buf_entries) { + read_size = dtl->buf_entries - i; - rc = copy_to_user(buf, &dtl->buf[last_idx], + rc = copy_to_user(buf, &dtl->buf[i], read_size * sizeof(struct dtl_entry)); if (rc) return -EFAULT; - last_idx = 0; + i = 0; n_req -= read_size; n_read += read_size; buf += read_size * sizeof(struct dtl_entry); } /* .. and now the head */ - read_size = min(n_req, cur_idx - last_idx); - rc = copy_to_user(buf, &dtl->buf[last_idx], - read_size * sizeof(struct dtl_entry)); + rc = copy_to_user(buf, &dtl->buf[i], n_req * sizeof(struct dtl_entry)); if (rc) return -EFAULT; - n_read += read_size; - dtl->last_idx += n_read; + n_read += n_req; return n_read * sizeof(struct dtl_entry); } @@ -263,6 +376,7 @@ static int dtl_init(void) /* set up the per-cpu log structures */ for_each_possible_cpu(i) { struct dtl *dtl = &per_cpu(cpu_dtl, i); + spin_lock_init(&dtl->lock); dtl->cpu = i; rc = dtl_setup_file(dtl);