kdb: Adopt scheduler's task clasification

Message ID	20210916154253.2731609-1-daniel.thompson@linaro.org
State	New
Headers	show Delivered-To: patches@linaro.org Received-SPF: pass (google.com: domain of daniel.thompson@linaro.org designates 209.85.220.41 as permitted sender) client-ip=209.85.220.41; From: Daniel Thompson <daniel.thompson@linaro.org> To: Jason Wessel <jason.wessel@windriver.com>, Daniel Thompson <daniel.thompson@linaro.org>, Douglas Anderson <dianders@chromium.org> Cc: Xiang wangx <wangxiang@cdjrlc.com>, jing yangyang <jing.yangyang@zte.com.cn>, kgdb-bugreport@lists.sourceforge.net, linux-kernel@vger.kernel.org, patches@linaro.org Subject: [PATCH] kdb: Adopt scheduler's task clasification Date: Thu, 16 Sep 2021 16:42:53 +0100 Message-Id: <20210916154253.2731609-1-daniel.thompson@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit
Series	kdb: Adopt scheduler's task clasification \| expand kdb: Adopt scheduler's task clasification

diff --git a/kernel/debug/kdb/kdb_bt.c b/kernel/debug/kdb/kdb_bt.c index 1f9f0e47aedaa..3368a2d15d73b 100644 --- a/kernel/debug/kdb/kdb_bt.c +++ b/kernel/debug/kdb/kdb_bt.c @@ -74,7 +74,7 @@ static void kdb_show_stack(struct task_struct *p, void *addr) */ static int -kdb_bt1(struct task_struct *p, unsigned long mask, bool btaprompt) +kdb_bt1(struct task_struct *p, const char *mask, bool btaprompt) { char ch; @@ -120,7 +120,7 @@ kdb_bt_cpu(unsigned long cpu) return; } - kdb_bt1(kdb_tsk, ~0UL, false); + kdb_bt1(kdb_tsk, "A", false); } int @@ -138,8 +138,8 @@ kdb_bt(int argc, const char **argv) if (strcmp(argv[0], "bta") == 0) { struct task_struct *g, *p; unsigned long cpu; - unsigned long mask = kdb_task_state_string(argc ? argv[1] : - NULL); + const char *mask = argc ? argv[1] : kdbgetenv("PS"); + if (argc == 0) kdb_ps_suppressed(); /* Run the active tasks first */ @@ -167,7 +167,7 @@ kdb_bt(int argc, const char **argv) return diag; p = find_task_by_pid_ns(pid, &init_pid_ns); if (p) - return kdb_bt1(p, ~0UL, false); + return kdb_bt1(p, "A", false); kdb_printf("No process with pid == %ld found\n", pid); return 0; } else if (strcmp(argv[0], "btt") == 0) { @@ -176,7 +176,7 @@ kdb_bt(int argc, const char **argv) diag = kdbgetularg((char *)argv[1], &addr); if (diag) return diag; - return kdb_bt1((struct task_struct *)addr, ~0UL, false); + return kdb_bt1((struct task_struct *)addr, "A", false); } else if (strcmp(argv[0], "btc") == 0) { unsigned long cpu = ~0; if (argc > 1) @@ -212,7 +212,7 @@ kdb_bt(int argc, const char **argv) kdb_show_stack(kdb_current_task, (void *)addr); return 0; } else { - return kdb_bt1(kdb_current_task, ~0UL, false); + return kdb_bt1(kdb_current_task, "A", false); } } diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c index fa6deda894a17..b2aadc23f4ca1 100644 --- a/kernel/debug/kdb/kdb_main.c +++ b/kernel/debug/kdb/kdb_main.c @@ -2271,17 +2271,15 @@ static int kdb_cpu(int argc, const char **argv) void kdb_ps_suppressed(void) { int idle = 0, daemon = 0; - unsigned long mask_I = kdb_task_state_string("I"), - mask_M = kdb_task_state_string("M"); unsigned long cpu; const struct task_struct *p, *g; for_each_online_cpu(cpu) { p = kdb_curr_task(cpu); - if (kdb_task_state(p, mask_I)) + if (kdb_task_state(p, "I")) ++idle; } for_each_process_thread(g, p) { - if (kdb_task_state(p, mask_M)) + if (kdb_task_state(p, "M")) ++daemon; } if (idle || daemon) { @@ -2300,7 +2298,7 @@ void kdb_ps_suppressed(void) /* * kdb_ps - This function implements the 'ps' command which shows a * list of the active processes. - * ps [DRSTCZEUIMA] All processes, optionally filtered by state + * ps [RSDTtXZPIMA] All processes, optionally filtered by state */ void kdb_ps1(const struct task_struct *p) { @@ -2333,14 +2331,15 @@ void kdb_ps1(const struct task_struct *p) static int kdb_ps(int argc, const char **argv) { struct task_struct *g, *p; - unsigned long mask, cpu; + const char *mask; + unsigned long cpu; if (argc == 0) kdb_ps_suppressed(); kdb_printf("%-*s Pid Parent [*] cpu State %-*s Command\n", (int)(2*sizeof(void *))+2, "Task Addr", (int)(2*sizeof(void *))+2, "Thread"); - mask = kdb_task_state_string(argc ? argv[1] : NULL); + mask = argc ? argv[1] : kdbgetenv("PS"); /* Run the active tasks first */ for_each_online_cpu(cpu) { if (KDB_FLAG(CMD_INTERRUPT)) @@ -2742,7 +2741,7 @@ static kdbtab_t maintab[] = { }, { .name = "bta", .func = kdb_bt, - .usage = "[D|R|S|T|C|Z|E|U|I|M|A]", + .usage = "[R|S|D|T|t|X|Z|P|I|M|A]", .help = "Backtrace all processes matching state flag", .flags = KDB_ENABLE_INSPECT, }, diff --git a/kernel/debug/kdb/kdb_private.h b/kernel/debug/kdb/kdb_private.h index 629590084a0dc..0d2f9feea0a46 100644 --- a/kernel/debug/kdb/kdb_private.h +++ b/kernel/debug/kdb/kdb_private.h @@ -190,10 +190,8 @@ extern char kdb_grep_string[]; extern int kdb_grep_leading; extern int kdb_grep_trailing; extern char *kdb_cmds[]; -extern unsigned long kdb_task_state_string(const char *); extern char kdb_task_state_char (const struct task_struct *); -extern unsigned long kdb_task_state(const struct task_struct *p, - unsigned long mask); +extern bool kdb_task_state(const struct task_struct *p, const char *mask); extern void kdb_ps_suppressed(void); extern void kdb_ps1(const struct task_struct *p); extern void kdb_send_sig(struct task_struct *p, int sig); diff --git a/kernel/debug/kdb/kdb_support.c b/kernel/debug/kdb/kdb_support.c index 7507d9a8dc6ac..2070f2527337d 100644 --- a/kernel/debug/kdb/kdb_support.c +++ b/kernel/debug/kdb/kdb_support.c @@ -473,82 +473,7 @@ int kdb_putword(unsigned long addr, unsigned long word, size_t size) return diag; } -/* - * kdb_task_state_string - Convert a string containing any of the - * letters DRSTCZEUIMA to a mask for the process state field and - * return the value. If no argument is supplied, return the mask - * that corresponds to environment variable PS, DRSTCZEU by - * default. - * Inputs: - * s String to convert - * Returns: - * Mask for process state. - * Notes: - * The mask folds data from several sources into a single long value, so - * be careful not to overlap the bits. TASK_* bits are in the LSB, - * special cases like UNRUNNABLE are in the MSB. As of 2.6.10-rc1 there - * is no overlap between TASK_* and EXIT_* but that may not always be - * true, so EXIT_* bits are shifted left 16 bits before being stored in - * the mask. - */ -/* unrunnable is < 0 */ -#define UNRUNNABLE (1UL << (8*sizeof(unsigned long) - 1)) -#define RUNNING (1UL << (8*sizeof(unsigned long) - 2)) -#define IDLE (1UL << (8*sizeof(unsigned long) - 3)) -#define DAEMON (1UL << (8*sizeof(unsigned long) - 4)) - -unsigned long kdb_task_state_string(const char *s) -{ - long res = 0; - if (!s) { - s = kdbgetenv("PS"); - if (!s) - s = "DRSTCZEU"; /* default value for ps */ - } - while (*s) { - switch (*s) { - case 'D': - res |= TASK_UNINTERRUPTIBLE; - break; - case 'R': - res |= RUNNING; - break; - case 'S': - res |= TASK_INTERRUPTIBLE; - break; - case 'T': - res |= TASK_STOPPED; - break; - case 'C': - res |= TASK_TRACED; - break; - case 'Z': - res |= EXIT_ZOMBIE << 16; - break; - case 'E': - res |= EXIT_DEAD << 16; - break; - case 'U': - res |= UNRUNNABLE; - break; - case 'I': - res |= IDLE; - break; - case 'M': - res |= DAEMON; - break; - case 'A': - res = ~0UL; - break; - default: - kdb_func_printf("unknown flag '%c' ignored\n", *s); - break; - } - ++s; - } - return res; -} /* * kdb_task_state_char - Return the character that represents the task state. @@ -559,7 +484,6 @@ unsigned long kdb_task_state_string(const char *s) */ char kdb_task_state_char (const struct task_struct *p) { - unsigned int p_state; unsigned long tmp; char state; int cpu; @@ -568,16 +492,20 @@ char kdb_task_state_char (const struct task_struct *p) copy_from_kernel_nofault(&tmp, (char *)p, sizeof(unsigned long))) return 'E'; - cpu = kdb_process_cpu(p); - p_state = READ_ONCE(p->__state); - state = (p_state == 0) ? 'R' : - (p_state < 0) ? 'U' : - (p_state & TASK_UNINTERRUPTIBLE) ? 'D' : - (p_state & TASK_STOPPED) ? 'T' : - (p_state & TASK_TRACED) ? 'C' : - (p->exit_state & EXIT_ZOMBIE) ? 'Z' : - (p->exit_state & EXIT_DEAD) ? 'E' : - (p_state & TASK_INTERRUPTIBLE) ? 'S' : '?'; + state = task_state_to_char((struct task_struct *) p); + + /* + * task_state_to_char() uses I(dle) differently to is_idle_task(). + * I(dle) tasks are (U)ninterruptible tasks that do not + * contribute to the load average and have nothing to do with + * code that runs on idle CPUs. + * + * For historic reasons we'd like to reserve I for idle CPUs in + * kdb so we must reclassify (I)dle tasks. + */ + if (state == 'I') + state = 'U'; + if (is_idle_task(p)) { /* Idle task. Is it really idle, apart from the kdb * interrupt? */ @@ -596,14 +524,24 @@ char kdb_task_state_char (const struct task_struct *p) * given by the mask. * Inputs: * p struct task for the process - * mask mask from kdb_task_state_string to select processes + * mask set of characters used to select processes; both NULL + * and the empty string mean adopt a default filter, which + * is to suppress sleeping system daemons and the idle tasks * Returns: * True if the process matches at least one criteria defined by the mask. */ -unsigned long kdb_task_state(const struct task_struct *p, unsigned long mask) +bool kdb_task_state(const struct task_struct *p, const char *mask) { - char state[] = { kdb_task_state_char(p), '\0' }; - return (mask & kdb_task_state_string(state)) != 0; + char state = kdb_task_state_char(p); + + if (!mask || mask[0] == '\0') + return state != 'I' && state != 'M'; + + /* A is a special case that matches all states */ + if (strchr(mask, 'A')) + return true; + + return strchr(mask, state); } /* Maintain a small stack of kdb_flags to allow recursion without disturbing

kdb: Adopt scheduler's task clasification

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