Remove some PR_SET_VMAs during pthread_create
PR_SET_VMA takes mmap_sem, which can cause contention and reduce
performance any time many threads are created at the same time,
like app startup.
Test: camera launch performance
Bug: 122471935
Change-Id: If7fa7ad99654c01d503f694976fd92bfd30d2afd
Merged-in: If7fa7ad99654c01d503f694976fd92bfd30d2afd
diff --git a/libc/bionic/pthread_create.cpp b/libc/bionic/pthread_create.cpp
index 21a707b..8825c6f 100644
--- a/libc/bionic/pthread_create.cpp
+++ b/libc/bionic/pthread_create.cpp
@@ -65,8 +65,6 @@
return false;
}
- prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, allocation, allocation_size, "bionic TLS guard");
-
// Carve out the writable TLS section.
thread->bionic_tls = reinterpret_cast<bionic_tls*>(static_cast<char*>(allocation) +
PTHREAD_GUARD_SIZE);
@@ -77,7 +75,6 @@
return false;
}
- prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, thread->bionic_tls, BIONIC_TLS_SIZE, "bionic TLS");
return true;
}
@@ -105,7 +102,6 @@
// We can only use const static allocated string for mapped region name, as Android kernel
// uses the string pointer directly when dumping /proc/pid/maps.
prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, ss.ss_sp, ss.ss_size, "thread signal stack");
- prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, stack_base, PTHREAD_GUARD_SIZE, "thread signal stack guard");
}
}
@@ -184,8 +180,6 @@
munmap(space, mmap_size);
return NULL;
}
- prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, space, stack_guard_size, "thread stack guard");
-
return space;
}