static int lowmem_shrink(struct shrinker *s, struct shrink_control *sc)
{
struct task_struct *p;
struct task_struct *selected[MANAGED_PROCESS_TYPES] = {NULL};
int rem = 0;
int tasksize;
int i;
int min_adj = OOM_ADJUST_MAX + 1;
int minfree = 0;
enum lowmem_process_type proc_type = KILLABLE_PROCESS;
int selected_tasksize[MANAGED_PROCESS_TYPES] = {0};
int selected_oom_adj[MANAGED_PROCESS_TYPES];
int array_size = ARRAY_SIZE(lowmem_adj);
int other_free = global_page_state(NR_FREE_PAGES);
int other_file = global_page_state(NR_FILE_PAGES) -
global_page_state(NR_SHMEM);
/*
* If we already have a death outstanding, then
* bail out right away; indicating to vmscan
* that we have nothing further to offer on
* this pass.
*
*/
if (lowmem_deathpending &&
time_before_eq(jiffies, lowmem_deathpending_timeout))
return 0;
if (lowmem_adj_size < array_size)
array_size = lowmem_adj_size;
if (lowmem_minfree_size < array_size)
array_size = lowmem_minfree_size;
for (i = 0; i < array_size; i++) {
if (other_free < lowmem_minfree[i] &&
other_file < lowmem_minfree[i]) {
min_adj = lowmem_adj[i];
break;
}
}
if (sc->nr_to_scan > 0)
lowmem_print(3, "lowmem_shrink %lu, %x, ofree %d %d, ma %d\n",
sc->nr_to_scan, sc->gfp_mask, other_free, other_file,
min_adj);
rem = global_page_state(NR_ACTIVE_ANON) +
global_page_state(NR_ACTIVE_FILE) +
global_page_state(NR_INACTIVE_ANON) +
global_page_state(NR_INACTIVE_FILE);
if (sc->nr_to_scan <= 0 || min_adj == OOM_ADJUST_MAX + 1) {
lowmem_print(5, "lowmem_shrink %lu, %x, return %d\n",
sc->nr_to_scan, sc->gfp_mask, rem);
return rem;
}
/* Set the initial oom_adj for each managed process type */
for (proc_type = KILLABLE_PROCESS; proc_type < MANAGED_PROCESS_TYPES; proc_type++)
selected_oom_adj[proc_type] = min_adj;
read_lock(&tasklist_lock);
for_each_process(p) {
struct mm_struct *mm;
struct signal_struct *sig;
int oom_adj;
task_lock(p);
mm = p->mm;
sig = p->signal;
if (!mm || !sig) {
task_unlock(p);
continue;
}
oom_adj = sig->oom_adj;
if (oom_adj < min_adj) {
task_unlock(p);
continue;
}
tasksize = get_mm_rss(mm);
task_unlock(p);
if (tasksize <= 0)
continue;
/* Initially consider the process as killable */
proc_type = KILLABLE_PROCESS;
#ifdef CONFIG_ANDROID_LOW_MEMORY_KILLER_DO_NOT_KILL_PROCESS
/* Check if the process name is contained inside the process to be preserved lists */
if (is_in_donotkill_proc_list(p->comm)) {
/* This user process must be preserved from killing */
proc_type = DO_NOT_KILL_PROCESS;
lowmem_print(2, "The process '%s' is inside the donotkill_proc_names", p->comm);
} else if (is_in_donotkill_sysproc_list(p->comm)) {
/* This system process must be preserved from killing */
proc_type = DO_NOT_KILL_SYSTEM_PROCESS;
lowmem_print(2, "The process '%s' is inside the donotkill_sysproc_names", p->comm);
}
#endif
if (selected[proc_type]) {
if (oom_adj < selected_oom_adj[proc_type])
continue;
if (oom_adj == selected_oom_adj[proc_type] &&
tasksize <= selected_tasksize[proc_type])
continue;
}
selected[proc_type] = p;
selected_tasksize[proc_type] = tasksize;
selected_oom_adj[proc_type] = oom_adj;
lowmem_print(2, "select %d (%s), adj %d, size %d, to kill\n",
p->pid, p->comm, oom_adj, tasksize);
}
/* For each managed process type check if a process to be killed has been found:
* - check first if a standard killable process has been found, if so kill it
* - if there is no killable process, then check if a user process has been found,
* if so kill it to prevent system slowdowns, hangs, etc.
* - if there is no killable and user process, then check if a system process has been found,
* if so kill it to prevent system slowdowns, hangs, etc. */
for (proc_type = KILLABLE_PROCESS; proc_type < MANAGED_PROCESS_TYPES; proc_type++) {
if (selected[proc_type]) {
lowmem_print(1, "Killing '%s' (%d), adj %d,\n" \
" to free %ldkB on behalf of '%s' (%d) because\n" \
" cache %ldkB is below limit %ldkB for oom_adj %d\n" \
" Free memory is %ldkB above reserved\n",
selected[proc_type]->comm, selected[proc_type]->pid,
selected_oom_adj[proc_type],
selected_tasksize[proc_type] * (long)(PAGE_SIZE / 1024),
current->comm, current->pid,
other_file * (long)(PAGE_SIZE / 1024),
minfree * (long)(PAGE_SIZE / 1024),
min_adj,
other_free * (long)(PAGE_SIZE / 1024));
lowmem_deathpending_timeout = jiffies + HZ;
send_sig(SIGKILL, selected[proc_type], 0);
set_tsk_thread_flag(selected[proc_type], TIF_MEMDIE);
rem -= selected_tasksize[proc_type];
break;
}
#ifdef CONFIG_HUAWEI_FEATURE_LOW_MEMORY_KILLER_STUB
sysLowKernel_write(selected);
#endif
}
lowmem_print(4, "lowmem_shrink %lu, %x, return %d\n",
sc->nr_to_scan, sc->gfp_mask, rem);
read_unlock(&tasklist_lock);
return rem;
}
static int lowmem_shrink(struct shrinker *s, struct shrink_control *sc)
{
struct task_struct *p;
struct task_struct *selected = NULL;
int rem = 0;
int tasksize;
int i;
int min_adj = OOM_ADJUST_MAX + 1;
int selected_tasksize = 0;
int selected_oom_adj;
int array_size = ARRAY_SIZE(lowmem_adj);
int other_free = global_page_state(NR_FREE_PAGES);
int other_file = global_page_state(NR_FILE_PAGES) -
global_page_state(NR_SHMEM);
/*
* If we already have a death outstanding, then
* bail out right away; indicating to vmscan
* that we have nothing further to offer on
* this pass.
*
*/
if (lowmem_deathpending &&
time_before_eq(jiffies, lowmem_deathpending_timeout))
return 0;
if (lowmem_adj_size < array_size)
array_size = lowmem_adj_size;
if (lowmem_minfree_size < array_size)
array_size = lowmem_minfree_size;
for (i = 0; i < array_size; i++) {
if (other_free < lowmem_minfree[i] &&
other_file < lowmem_minfree[i]) {
min_adj = lowmem_adj[i];
break;
}
}
if (sc->nr_to_scan > 0)
lowmem_print(3, "lowmem_shrink %lu, %x, ofree %d %d, ma %d\n",
sc->nr_to_scan, sc->gfp_mask, other_free, other_file,
min_adj);
rem = global_page_state(NR_ACTIVE_ANON) +
global_page_state(NR_ACTIVE_FILE) +
global_page_state(NR_INACTIVE_ANON) +
global_page_state(NR_INACTIVE_FILE);
if (sc->nr_to_scan <= 0 || min_adj == OOM_ADJUST_MAX + 1) {
lowmem_print(5, "lowmem_shrink %lu, %x, return %d\n",
sc->nr_to_scan, sc->gfp_mask, rem);
return rem;
}
selected_oom_adj = min_adj;
read_lock(&tasklist_lock);
for_each_process(p) {
struct mm_struct *mm;
struct signal_struct *sig;
int oom_adj;
task_lock(p);
mm = p->mm;
sig = p->signal;
if (!mm || !sig) {
task_unlock(p);
continue;
}
oom_adj = sig->oom_adj;
if (oom_adj < min_adj) {
task_unlock(p);
continue;
}
tasksize = get_mm_rss(mm);
task_unlock(p);
if (tasksize <= 0)
continue;
if (selected) {
if (oom_adj < selected_oom_adj)
continue;
if (oom_adj == selected_oom_adj &&
tasksize <= selected_tasksize)
continue;
}
selected = p;
selected_tasksize = tasksize;
selected_oom_adj = oom_adj;
lowmem_print(2, "select %d (%s), adj %d, size %d, to kill\n",
p->pid, p->comm, oom_adj, tasksize);
}
if (selected) {
lowmem_print(1, "send sigkill to %d (%s), adj %d, size %d\n",
selected->pid, selected->comm,
selected_oom_adj, selected_tasksize);
lowmem_deathpending = selected;
lowmem_deathpending_timeout = jiffies + HZ;
#ifdef CONFIG_HUAWEI_FEATURE_LOW_MEMORY_KILLER_STUB
sysLowKernel_write(selected);
#endif
force_sig(SIGKILL, selected);
rem -= selected_tasksize;
}
lowmem_print(4, "lowmem_shrink %lu, %x, return %d\n",
sc->nr_to_scan, sc->gfp_mask, rem);
read_unlock(&tasklist_lock);
return rem;
}
