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Commit 360a113e authored by Vic Yang's avatar Vic Yang
Browse files

lmkd: Do not downgrade/ignore events when swap is full 

When the swap space is full, a pressure event is unlikely to resolve by
itself.  In this case, do not downgrade or ignore the events.

Bug: 112056451
Test: Fill up swap on a 1GB device and check critical vmpressure events
      are not downgraded.
Change-Id: If154dc364711bf7c86f32e24ddcd10be359386de
parent 5d707816

lmkd/lmkd.c

+23 −13
Original line number Diff line number Diff line
@@ -116,6 +116,7 @@ static bool kill_heaviest_task; 
static unsigned long kill_timeout_ms;

static bool use_minfree_levels;

static bool per_app_memcg;

static int swap_free_low_percentage;



/* data required to handle events */

struct event_handler_info {
@@ -194,6 +195,7 @@ enum meminfo_field { 
    MI_BUFFERS,

    MI_SHMEM,

    MI_UNEVICTABLE,

    MI_TOTAL_SWAP,

    MI_FREE_SWAP,

    MI_DIRTY,

    MI_FIELD_COUNT
@@ -206,6 +208,7 @@ static const char* const meminfo_field_names[MI_FIELD_COUNT] = { 
    "Buffers:",

    "Shmem:",

    "Unevictable:",

    "SwapTotal:",

    "SwapFree:",

    "Dirty:",

};
@@ -218,6 +221,7 @@ union meminfo { 
        int64_t buffers;

        int64_t shmem;

        int64_t unevictable;

        int64_t total_swap;

        int64_t free_swap;

        int64_t dirty;

        /* fields below are calculated rather than read from the file */
@@ -1296,6 +1300,10 @@ static void mp_event_common(int data, uint32_t events __unused) { 
        }

    }



    // If we still have enough swap space available, check if we want to

    // ignore/downgrade pressure events.

    if (mi.field.free_swap >=

        mi.field.total_swap * swap_free_low_percentage / 100) {

        // If the pressure is larger than downgrade_pressure lmk will not

        // kill any process, since enough memory is available.

        if (mem_pressure > downgrade_pressure) {
@@ -1303,14 +1311,14 @@ static void mp_event_common(int data, uint32_t events __unused) { 
                ALOGI("Ignore %s memory pressure", level_name[level]);

            }

            return;

    } else if (level == VMPRESS_LEVEL_CRITICAL &&

               mem_pressure > upgrade_pressure) {

        } else if (level == VMPRESS_LEVEL_CRITICAL && mem_pressure > upgrade_pressure) {

            if (debug_process_killing) {

                ALOGI("Downgrade critical memory pressure");

            }

            // Downgrade event, since enough memory available.

            level = downgrade_level(level);

        }

    }



do_kill:

    if (low_ram_device) {
@@ -1580,6 +1588,8 @@ int main(int argc __unused, char **argv __unused) { 
        property_get_bool("ro.lmk.use_minfree_levels", false);

    per_app_memcg =

        property_get_bool("ro.config.per_app_memcg", low_ram_device);

    swap_free_low_percentage =

        property_get_int32("ro.lmk.swap_free_low_percentage", 10);



#ifdef LMKD_LOG_STATS

    statslog_init(&log_ctx, &enable_stats_log);