mirror of
https://git.haproxy.org/git/haproxy.git/
synced 2025-11-24 04:11:02 +01:00
9a6ecbd590
The thread dump mechanism that is used by "show threads" and by the panic dump is overly complicated due to an initial misdesign. It firsts wakes all threads, then serializes their dumps, then releases them, while taking extreme care not to face colliding dumps. In fact this is not what we need and it reached a limit where big machines cannot dump all their threads anymore due to buffer size limitations. What is needed instead is to be able to dump *one* thread, and to let the requester iterate on all threads. That's what this patch does. It adds the thread_dump_buffer to the struct thread_ctx so that the requester offers the buffer to the thread that is about to be dumped. This buffer also serves as a lock. A thread at rest has a NULL, a valid pointer indicates the thread is using it, and 0x1 (NULL+1) is used by the dumped thread to tell the requester it's done. This makes sure that a given thread is dumped once at a time. In addition to this, the calling thread decides whether it accesses the thread by itself or via the debug signal handler, in order to get a backtrace. This is much saner because the calling thread is free to do whatever it wants with the buffer after each thread is dumped, and there is no dependency between threads, once they've dumped, they're free to continue (and possibly to dump for another requester if needed). Finally, when the THREAD_DUMP feature is disabled and the debug signal is not used, the requester accesses the thread by itself like before. For now we still have the buffer size limitation but it will be addressed in future patches.
173 lines
7.8 KiB
C
173 lines
7.8 KiB
C
/*
|
|
* include/haproxy/tinfo-t.h
|
|
* Definitions of the thread_info structure.
|
|
*
|
|
* Copyright (C) 2020 Willy Tarreau - w@1wt.eu
|
|
*
|
|
* This library is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation, version 2.1
|
|
* exclusively.
|
|
*
|
|
* This library 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
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with this library; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
#ifndef _HAPROXY_TINFO_T_H
|
|
#define _HAPROXY_TINFO_T_H
|
|
|
|
#include <import/ebtree-t.h>
|
|
|
|
#include <haproxy/api-t.h>
|
|
#include <haproxy/freq_ctr-t.h>
|
|
#include <haproxy/thread-t.h>
|
|
|
|
/* forward declarations for types used below */
|
|
struct buffer;
|
|
|
|
/* Threads sets are known either by a set of absolute thread numbers, or by a
|
|
* set of relative thread numbers within a group, for each group. The default
|
|
* is the absolute mode and corresponds to the case where no group is known
|
|
* (nbgrp == 0). The mode may only be changed when the set is empty (use
|
|
* thread_set_is_empty() for this).
|
|
*/
|
|
struct thread_set {
|
|
union {
|
|
ulong abs[(MAX_THREADS + LONGBITS - 1) / LONGBITS];
|
|
ulong rel[MAX_TGROUPS];
|
|
};
|
|
ulong grps; /* bit field of all non-empty groups, 0 for abs */
|
|
};
|
|
|
|
/* tasklet classes */
|
|
enum {
|
|
TL_URGENT = 0, /* urgent tasklets (I/O callbacks) */
|
|
TL_NORMAL = 1, /* normal tasks */
|
|
TL_BULK = 2, /* bulk task/tasklets, streaming I/Os */
|
|
TL_HEAVY = 3, /* heavy computational tasklets (e.g. TLS handshakes) */
|
|
TL_CLASSES /* must be last */
|
|
};
|
|
|
|
/* thread_ctx flags, for ha_thread_ctx[].flags. These flags describe the
|
|
* thread's state and are visible to other threads, so they must be used
|
|
* with atomic ops.
|
|
*/
|
|
#define TH_FL_STUCK 0x00000001
|
|
#define TH_FL_TASK_PROFILING 0x00000002
|
|
#define TH_FL_NOTIFIED 0x00000004 /* task was notified about the need to wake up */
|
|
#define TH_FL_SLEEPING 0x00000008 /* thread won't check its task list before next wakeup */
|
|
#define TH_FL_STARTED 0x00000010 /* set once the thread starts */
|
|
#define TH_FL_IN_LOOP 0x00000020 /* set only inside the polling loop */
|
|
|
|
|
|
/* Thread group information. This defines a base and a count of global thread
|
|
* IDs which belong to it, and which can be looked up into thread_info/ctx. It
|
|
* is set up during parsing and is stable during operation. Thread groups start
|
|
* at 1 so tgroup[0] describes thread group 1.
|
|
*/
|
|
struct tgroup_info {
|
|
ulong threads_enabled; /* mask of threads enabled in this group */
|
|
uint base; /* first thread in this group */
|
|
uint count; /* number of threads in this group */
|
|
ulong tgid_bit; /* bit corresponding to the tgroup ID */
|
|
|
|
/* pad to cache line (64B) */
|
|
char __pad[0]; /* unused except to check remaining room */
|
|
char __end[0] __attribute__((aligned(64)));
|
|
};
|
|
|
|
/* This structure describes the group-specific context (e.g. active threads
|
|
* etc). It uses one cache line per thread to limit false sharing.
|
|
*/
|
|
struct tgroup_ctx {
|
|
ulong threads_harmless; /* mask of threads that are not modifying anything */
|
|
ulong threads_idle; /* mask of threads idling in the poller */
|
|
ulong stopping_threads; /* mask of threads currently stopping */
|
|
|
|
struct eb_root timers; /* wait queue (sorted timers tree, global, accessed under wq_lock) */
|
|
|
|
uint niced_tasks; /* number of niced tasks in this group's run queues */
|
|
|
|
/* pad to cache line (64B) */
|
|
char __pad[0]; /* unused except to check remaining room */
|
|
char __end[0] __attribute__((aligned(64)));
|
|
};
|
|
|
|
/* This structure describes all the per-thread info we need. When threads are
|
|
* disabled, it contains the same info for the single running thread. This is
|
|
* stable across all of a thread's life, and is being pointed to by the
|
|
* thread-local "ti" pointer.
|
|
*/
|
|
struct thread_info {
|
|
const struct tgroup_info *tg; /* config of the thread-group this thread belongs to */
|
|
struct tgroup_ctx *tg_ctx; /* context of the thread-group this thread belongs to */
|
|
uint tid, ltid; /* process-wide and group-wide thread ID (start at 0) */
|
|
ulong ltid_bit; /* bit masks for the tid/ltid */
|
|
uint tgid; /* ID of the thread group this thread belongs to (starts at 1; 0=unset) */
|
|
|
|
/* pad to cache line (64B) */
|
|
char __pad[0]; /* unused except to check remaining room */
|
|
char __end[0] __attribute__((aligned(64)));
|
|
};
|
|
|
|
/* This structure describes all the per-thread context we need. This is
|
|
* essentially the scheduler-specific stuff and a few important per-thread
|
|
* lists that need to be thread-local. We take care of splitting this into
|
|
* separate cache lines.
|
|
*/
|
|
struct thread_ctx {
|
|
// first and second cache lines on 64 bits: thread-local operations only.
|
|
struct eb_root timers; /* tree constituting the per-thread wait queue */
|
|
struct eb_root rqueue; /* tree constituting the per-thread run queue */
|
|
struct task *current; /* current task (not tasklet) */
|
|
int current_queue; /* points to current tasklet list being run, -1 if none */
|
|
unsigned int nb_tasks; /* number of tasks allocated on this thread */
|
|
uint8_t tl_class_mask; /* bit mask of non-empty tasklets classes */
|
|
|
|
// 7 bytes hole here
|
|
struct list pool_lru_head; /* oldest objects in thread-local pool caches */
|
|
struct list buffer_wq; /* buffer waiters */
|
|
struct list streams; /* list of streams attached to this thread */
|
|
struct list quic_conns; /* list of active quic-conns attached to this thread */
|
|
struct list quic_conns_clo; /* list of closing quic-conns attached to this thread */
|
|
|
|
ALWAYS_ALIGN(2*sizeof(void*));
|
|
struct list tasklets[TL_CLASSES]; /* tasklets (and/or tasks) to run, by class */
|
|
|
|
// third cache line here on 64 bits: accessed mostly using atomic ops
|
|
ALWAYS_ALIGN(64);
|
|
struct mt_list shared_tasklet_list; /* Tasklet to be run, woken up by other threads */
|
|
unsigned int rqueue_ticks; /* Insertion counter for the run queue */
|
|
unsigned int rq_total; /* total size of the run queue, prio_tree + tasklets */
|
|
int tasks_in_list; /* Number of tasks in the per-thread tasklets list */
|
|
uint idle_pct; /* idle to total ratio over last sample (percent) */
|
|
uint flags; /* thread flags, TH_FL_*, atomic! */
|
|
/* 32-bit hole here */
|
|
|
|
uint32_t sched_wake_date; /* current task/tasklet's wake date or 0 */
|
|
uint32_t sched_call_date; /* current task/tasklet's call date (valid if sched_wake_date > 0) */
|
|
struct sched_activity *sched_profile_entry; /* profile entry in use by the current task/tasklet, only if sched_wake_date>0 */
|
|
|
|
uint64_t prev_cpu_time; /* previous per thread CPU time */
|
|
uint64_t prev_mono_time; /* previous system wide monotonic time */
|
|
|
|
struct eb_root rqueue_shared; /* run queue fed by other threads */
|
|
__decl_thread(HA_SPINLOCK_T rqsh_lock); /* lock protecting the shared runqueue */
|
|
|
|
struct freq_ctr out_32bps; /* #of 32-byte blocks emitted per second */
|
|
unsigned long long out_bytes; /* total #of bytes emitted */
|
|
unsigned long long spliced_out_bytes; /* total #of bytes emitted though a kernel pipe */
|
|
struct buffer *thread_dump_buffer; /* NULL out of dump, valid during a dump, 0x01 once done */
|
|
|
|
ALWAYS_ALIGN(128);
|
|
};
|
|
|
|
|
|
#endif /* _HAPROXY_TINFO_T_H */
|