Linux內(nèi)存的分配管理與內(nèi)存回收基本框架

linux-src/mm/util.c:__vm_enough_memory。

5.2、物理內(nèi)存OOM

bool out_of_memory(struct oom_control *oc){    select_bad_process(oc);    oom_kill_process(oc, "Out of memory");}

• 1先選擇一個(gè)要?dú)⑺赖倪M(jìn)程

• 2殺死它，就是這么簡單。

下面我們來分析一下select_bad_process函數(shù)的實(shí)現(xiàn)：

static void select_bad_process(struct oom_control *oc){  oc->chosen_points = LONG_MIN;  struct task_struct *p;
  rcu_read_lock();  for_each_process(p)    if (oom_evaluate_task(p, oc))      break;  rcu_read_unlock();}

static int oom_evaluate_task(struct task_struct *task, void *arg){  struct oom_control *oc = arg;  long points;  if (oom_unkillable_task(task))    goto next;  /* p may not have freeable memory in nodemask */  if (!is_memcg_oom(oc) && !oom_cpuset_eligible(task, oc))    goto next;  if (oom_task_origin(task)) {    points = LONG_MAX;    goto select;  }  points = oom_badness(task, oc->totalpages);  if (points == LONG_MIN || points < oc->chosen_points)    goto next;select:  if (oc->chosen)    put_task_struct(oc->chosen);  get_task_struct(task);  oc->chosen = task;  oc->chosen_points = points;next:  return 0;abort:  if (oc->chosen)    put_task_struct(oc->chosen);  oc->chosen = (void *)-1UL;  return 1;}

long oom_badness(struct task_struct *p, unsigned long totalpages){  long points;  long adj;  if (oom_unkillable_task(p))    return LONG_MIN;  p = find_lock_task_mm(p);  if (!p)    return LONG_MIN;  adj = (long)p->signal->oom_score_adj;  if (adj == OOM_SCORE_ADJ_MIN ||      test_bit(MMF_OOM_SKIP, &p->mm->flags) ||      in_vfork(p)) {    task_unlock(p);    return LONG_MIN;  }  points = get_mm_rss(p->mm) + get_mm_counter(p->mm, MM_SWAPENTS) +    mm_pgtables_bytes(p->mm) / PAGE_SIZE;  task_unlock(p);  adj *= totalpages / 1000;  points += adj;  return points;}

5.3、安卓LMK簡介

6.總結(jié)