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Commit d39adf2a authored by Daniel Colascione's avatar Daniel Colascione
Browse files

Add MCL_ONFAULT to mlockall 

This way, we don't fault in the entirety of our DSOs immediately;
instead, used pages are "sticky" in memory. Works only on kernel 4.4
and up: downlevel, we ignore the mlockall failure.

Once we get statically-linked lmkd in better shape, we'll just switch
to that.

Change-Id: I07a75ee3bc1264a1db41635c2acf611fede99b91
parent a0e50d0b

lmkd/lmkd.c

+10 −1
Original line number Diff line number Diff line
@@ -900,7 +900,16 @@ int main(int argc __unused, char **argv __unused) { 
    downgrade_pressure = (int64_t)property_get_int32("ro.lmk.downgrade_pressure", 60);

    is_go_device = property_get_bool("ro.config.low_ram", false);



    if (mlockall(MCL_CURRENT | MCL_FUTURE))

    // MCL_ONFAULT pins pages as they fault instead of loading

    // everything immediately all at once. (Which would be bad,

    // because as of this writing, we have a lot of mapped pages we

    // never use.) Old kernels will see MCL_ONFAULT and fail with

    // EINVAL; we ignore this failure.

    //

    // N.B. read the man page for mlockall. MCL_CURRENT | MCL_ONFAULT

    // pins ⊆ MCL_CURRENT, converging to just MCL_CURRENT as we fault

    // in pages.

    if (mlockall(MCL_CURRENT | MCL_FUTURE | MCL_ONFAULT) && errno != EINVAL)

        ALOGW("mlockall failed: errno=%d", errno);



    sched_setscheduler(0, SCHED_FIFO, &param);