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ANDROID: mm: oom_kill: reap memory of a task that receives SIGKILL

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Free the pages parallely for a task that receives SIGKILL, from ULMK
process, using the oom_reaper. This freeing of pages will help to give
the pages to buddy system well advance.

Add the boot param, reap_mem_when_killed_by=, that configures the
process name, the kill signal to a process from which makes its memory
reaped by oom reaper.

As an example, when reap_mem_when_killed_by=lmkd, then all the processes
that receives the kill signal from lmkd is added to oom reaper.

Not initializing this param makes this feature disabled.

Change-Id: I21adb95de5e380a80d7eb0b87d9b5b553f52e28a
Bug: 171763461
Signed-off-by: Charan Teja Reddy <charante@codeaurora.org>
Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>
This commit is contained in:
Charan Teja Reddy
2018-05-01 20:20:20 +05:30
committed by Suren Baghdasaryan
parent 51ca215606
commit a7af91adc7
4 changed files with 55 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
Documentation/admin-guide/kernel-parameters.txt
View File

@@ -4604,6 +4604,10 @@
(that will set all pages holding image data
during restoration read-only).
reap_mem_when_killed_by=
The name of a process, the kill signal from which to a process
make its memory reaped with oom reaper.
retain_initrd [RAM] Keep initrd memory after extraction
rfkill.default_state=

3
include/linux/oom.h
View File

@@ -127,4 +127,7 @@ extern struct task_struct *find_lock_task_mm(struct task_struct *p);
extern int sysctl_oom_dump_tasks;
extern int sysctl_oom_kill_allocating_task;
extern int sysctl_panic_on_oom;
/* calls for LMK reaper */
extern void add_to_oom_reaper(struct task_struct *p);
#endif /* _INCLUDE_LINUX_OOM_H */

19
kernel/signal.c
View File

@@ -46,6 +46,7 @@
#include <linux/livepatch.h>
#include <linux/cgroup.h>
#include <linux/audit.h>
#include <linux/oom.h>
#define CREATE_TRACE_POINTS
#include <trace/events/signal.h>
@@ -64,6 +65,18 @@ static struct kmem_cache *sigqueue_cachep;
int print_fatal_signals __read_mostly;
static char reaper_comm[TASK_COMM_LEN];
static __init int setup_mem_reap(char *str)
{
if (!str)
return 0;
strlcpy(reaper_comm, str, TASK_COMM_LEN);
return 1;
}
__setup("reap_mem_when_killed_by=", setup_mem_reap);
static void __user *sig_handler(struct task_struct *t, int sig)
{
return t->sighand->action[sig - 1].sa.sa_handler;
@@ -1411,8 +1424,12 @@ int group_send_sig_info(int sig, struct kernel_siginfo *info,
ret = check_kill_permission(sig, info, p);
rcu_read_unlock();
if (!ret && sig)
if (!ret && sig) {
ret = do_send_sig_info(sig, info, p, type);
if (!ret && sig == SIGKILL &&
!strcmp(current->comm, reaper_comm))
add_to_oom_reaper(p);
}
return ret;
}

36
mm/oom_kill.c
View File

@@ -685,6 +685,20 @@ static inline void wake_oom_reaper(struct task_struct *tsk)
}
#endif /* CONFIG_MMU */
/**
* tsk->mm has to be non NULL and caller has to guarantee it is stable (either
* under task_lock or operate on the current).
*/
static void __mark_oom_victim(struct task_struct *tsk)
{
struct mm_struct *mm = tsk->mm;
if (!cmpxchg(&tsk->signal->oom_mm, NULL, mm)) {
mmgrab(tsk->signal->oom_mm);
set_bit(MMF_OOM_VICTIM, &mm->flags);
}
}
/**
* mark_oom_victim - mark the given task as OOM victim
* @tsk: task to mark
@@ -697,18 +711,13 @@ static inline void wake_oom_reaper(struct task_struct *tsk)
*/
static void mark_oom_victim(struct task_struct *tsk)
{
struct mm_struct *mm = tsk->mm;
WARN_ON(oom_killer_disabled);
/* OOM killer might race with memcg OOM */
if (test_and_set_tsk_thread_flag(tsk, TIF_MEMDIE))
return;
/* oom_mm is bound to the signal struct life time. */
if (!cmpxchg(&tsk->signal->oom_mm, NULL, mm)) {
mmgrab(tsk->signal->oom_mm);
set_bit(MMF_OOM_VICTIM, &mm->flags);
}
__mark_oom_victim(tsk);
/*
* Make sure that the task is woken up from uninterruptible sleep
@@ -1140,3 +1149,18 @@ void pagefault_out_of_memory(void)
out_of_memory(&oc);
mutex_unlock(&oom_lock);
}
void add_to_oom_reaper(struct task_struct *p)
{
p = find_lock_task_mm(p);
if (!p)
return;
get_task_struct(p);
if (task_will_free_mem(p)) {
__mark_oom_victim(p);
wake_oom_reaper(p);
}
task_unlock(p);
put_task_struct(p);
}