diff options
Diffstat (limited to 'arch/powerpc/platforms/pseries/dtl.c')
| -rw-r--r-- | arch/powerpc/platforms/pseries/dtl.c | 170 |
1 files changed, 110 insertions, 60 deletions
diff --git a/arch/powerpc/platforms/pseries/dtl.c b/arch/powerpc/platforms/pseries/dtl.c index ef6595153642..f293588b8c7b 100644 --- a/arch/powerpc/platforms/pseries/dtl.c +++ b/arch/powerpc/platforms/pseries/dtl.c @@ -1,38 +1,26 @@ +// SPDX-License-Identifier: GPL-2.0-or-later /* * Virtual Processor Dispatch Trace Log * * (C) Copyright IBM Corporation 2009 * * Author: Jeremy Kerr <jk@ozlabs.org> - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2, or (at your option) - * any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include <linux/slab.h> #include <linux/spinlock.h> #include <asm/smp.h> #include <linux/uaccess.h> +#include <linux/debugfs.h> #include <asm/firmware.h> +#include <asm/dtl.h> #include <asm/lppaca.h> -#include <asm/debugfs.h> #include <asm/plpar_wrappers.h> #include <asm/machdep.h> +#ifdef CONFIG_DTL struct dtl { struct dtl_entry *buf; - struct dentry *file; int cpu; int buf_entries; u64 last_idx; @@ -40,13 +28,7 @@ struct dtl { }; static DEFINE_PER_CPU(struct dtl, cpu_dtl); -/* - * Dispatch trace log event mask: - * 0x7: 0x1: voluntary virtual processor waits - * 0x2: time-slice preempts - * 0x4: virtual partition memory page faults - */ -static u8 dtl_event_mask = 0x7; +static u8 dtl_event_mask = DTL_LOG_ALL; /* @@ -56,12 +38,20 @@ static u8 dtl_event_mask = 0x7; static int dtl_buf_entries = N_DISPATCH_LOG; #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE + +/* + * When CONFIG_VIRT_CPU_ACCOUNTING_NATIVE = y, the cpu accounting code controls + * reading from the dispatch trace log. If other code wants to consume + * DTL entries, it can set this pointer to a function that will get + * called once for each DTL entry that gets processed. + */ +static void (*dtl_consumer)(struct dtl_entry *entry, u64 index); + 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); @@ -111,7 +101,6 @@ static int dtl_start(struct dtl *dtl) 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; @@ -129,7 +118,7 @@ static void dtl_stop(struct dtl *dtl) dtlr->buf = NULL; /* restore dtl_enable_mask */ - lppaca_of(dtl->cpu).dtl_enable_mask = dtlr->saved_dtl_mask; + lppaca_of(dtl->cpu).dtl_enable_mask = DTL_LOG_PREEMPT; if (atomic_dec_and_test(&dtl_count)) dtl_consumer = NULL; @@ -201,11 +190,16 @@ static int dtl_enable(struct dtl *dtl) if (dtl->buf) return -EBUSY; + /* ensure there are no other conflicting dtl users */ + if (!down_read_trylock(&dtl_access_lock)) + return -EBUSY; + n_entries = dtl_buf_entries; buf = kmem_cache_alloc_node(dtl_cache, GFP_KERNEL, cpu_to_node(dtl->cpu)); if (!buf) { printk(KERN_WARNING "%s: buffer alloc failed for cpu %d\n", __func__, dtl->cpu); + up_read(&dtl_access_lock); return -ENOMEM; } @@ -222,8 +216,11 @@ static int dtl_enable(struct dtl *dtl) } spin_unlock(&dtl->lock); - if (rc) + if (rc) { + up_read(&dtl_access_lock); kmem_cache_free(dtl_cache, buf); + } + return rc; } @@ -235,6 +232,7 @@ static void dtl_disable(struct dtl *dtl) dtl->buf = NULL; dtl->buf_entries = 0; spin_unlock(&dtl->lock); + up_read(&dtl_access_lock); } /* file interface */ @@ -327,51 +325,32 @@ static const struct file_operations dtl_fops = { .open = dtl_file_open, .release = dtl_file_release, .read = dtl_file_read, - .llseek = no_llseek, }; static struct dentry *dtl_dir; -static int dtl_setup_file(struct dtl *dtl) +static void dtl_setup_file(struct dtl *dtl) { char name[10]; sprintf(name, "cpu-%d", dtl->cpu); - dtl->file = debugfs_create_file(name, 0400, dtl_dir, dtl, &dtl_fops); - if (!dtl->file) - return -ENOMEM; - - return 0; + debugfs_create_file(name, 0400, dtl_dir, dtl, &dtl_fops); } static int dtl_init(void) { - struct dentry *event_mask_file, *buf_entries_file; - int rc, i; + int i; if (!firmware_has_feature(FW_FEATURE_SPLPAR)) return -ENODEV; /* set up common debugfs structure */ - rc = -ENOMEM; - dtl_dir = debugfs_create_dir("dtl", powerpc_debugfs_root); - if (!dtl_dir) { - printk(KERN_WARNING "%s: can't create dtl root dir\n", - __func__); - goto err; - } - - event_mask_file = debugfs_create_x8("dtl_event_mask", 0600, - dtl_dir, &dtl_event_mask); - buf_entries_file = debugfs_create_u32("dtl_buf_entries", 0400, - dtl_dir, &dtl_buf_entries); + dtl_dir = debugfs_create_dir("dtl", arch_debugfs_dir); - if (!event_mask_file || !buf_entries_file) { - printk(KERN_WARNING "%s: can't create dtl files\n", __func__); - goto err_remove_dir; - } + debugfs_create_x8("dtl_event_mask", 0600, dtl_dir, &dtl_event_mask); + debugfs_create_u32("dtl_buf_entries", 0400, dtl_dir, &dtl_buf_entries); /* set up the per-cpu log structures */ for_each_possible_cpu(i) { @@ -379,16 +358,87 @@ static int dtl_init(void) spin_lock_init(&dtl->lock); dtl->cpu = i; - rc = dtl_setup_file(dtl); - if (rc) - goto err_remove_dir; + dtl_setup_file(dtl); } return 0; - -err_remove_dir: - debugfs_remove_recursive(dtl_dir); -err: - return rc; } machine_arch_initcall(pseries, dtl_init); +#endif /* CONFIG_DTL */ + +#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE +/* + * Scan the dispatch trace log and count up the stolen time. + * Should be called with interrupts disabled. + */ +static notrace u64 scan_dispatch_log(u64 stop_tb) +{ + u64 i = local_paca->dtl_ridx; + struct dtl_entry *dtl = local_paca->dtl_curr; + struct dtl_entry *dtl_end = local_paca->dispatch_log_end; + struct lppaca *vpa = local_paca->lppaca_ptr; + u64 tb_delta; + u64 stolen = 0; + u64 dtb; + + if (!dtl) + return 0; + + if (i == be64_to_cpu(vpa->dtl_idx)) + return 0; + while (i < be64_to_cpu(vpa->dtl_idx)) { + dtb = be64_to_cpu(dtl->timebase); + tb_delta = be32_to_cpu(dtl->enqueue_to_dispatch_time) + + be32_to_cpu(dtl->ready_to_enqueue_time); + barrier(); + if (i + N_DISPATCH_LOG < be64_to_cpu(vpa->dtl_idx)) { + /* buffer has overflowed */ + i = be64_to_cpu(vpa->dtl_idx) - N_DISPATCH_LOG; + dtl = local_paca->dispatch_log + (i % N_DISPATCH_LOG); + continue; + } + if (dtb > stop_tb) + break; +#ifdef CONFIG_DTL + if (dtl_consumer) + dtl_consumer(dtl, i); +#endif + stolen += tb_delta; + ++i; + ++dtl; + if (dtl == dtl_end) + dtl = local_paca->dispatch_log; + } + local_paca->dtl_ridx = i; + local_paca->dtl_curr = dtl; + return stolen; +} + +/* + * Accumulate stolen time by scanning the dispatch trace log. + * Called on entry from user mode. + */ +void notrace pseries_accumulate_stolen_time(void) +{ + u64 sst, ust; + struct cpu_accounting_data *acct = &local_paca->accounting; + + sst = scan_dispatch_log(acct->starttime_user); + ust = scan_dispatch_log(acct->starttime); + acct->stime -= sst; + acct->utime -= ust; + acct->steal_time += ust + sst; +} + +u64 pseries_calculate_stolen_time(u64 stop_tb) +{ + if (!firmware_has_feature(FW_FEATURE_SPLPAR)) + return 0; + + if (get_paca()->dtl_ridx != be64_to_cpu(get_lppaca()->dtl_idx)) + return scan_dispatch_log(stop_tb); + + return 0; +} + +#endif |