diff options
| -rw-r--r-- | Kernel/ProcessGroup.cpp | 17 | ||||
| -rw-r--r-- | Kernel/ProcessGroup.h | 2 |
2 files changed, 17 insertions, 2 deletions
diff --git a/Kernel/ProcessGroup.cpp b/Kernel/ProcessGroup.cpp index 3a92151e51..23c429815b 100644 --- a/Kernel/ProcessGroup.cpp +++ b/Kernel/ProcessGroup.cpp @@ -30,18 +30,31 @@ RefPtr<ProcessGroup> ProcessGroup::create(ProcessGroupID pgid) RefPtr<ProcessGroup> ProcessGroup::find_or_create(ProcessGroupID pgid) { + // Avoid allocating under spinlock, this compromises by wasting the + // allocation when we race with another process to see if they have + // already created a process group. + auto process_group = adopt_ref_if_nonnull(new ProcessGroup(pgid)); ScopedSpinLock lock(g_process_groups_lock); - if (auto existing = from_pgid(pgid)) + if (auto existing = from_pgid_nolock(pgid)) return existing.release_nonnull(); - return create(pgid); + if (!process_group) + return {}; + + g_process_groups->prepend(process_group); + return process_group; } RefPtr<ProcessGroup> ProcessGroup::from_pgid(ProcessGroupID pgid) { ScopedSpinLock lock(g_process_groups_lock); + return from_pgid_nolock(pgid); +} +RefPtr<ProcessGroup> ProcessGroup::from_pgid_nolock(ProcessGroupID pgid) +{ + VERIFY(g_process_groups_lock.own_lock()); for (auto& group : *g_process_groups) { if (group.pgid() == pgid) return &group; diff --git a/Kernel/ProcessGroup.h b/Kernel/ProcessGroup.h index 8ae5f295f5..fac329f1ec 100644 --- a/Kernel/ProcessGroup.h +++ b/Kernel/ProcessGroup.h @@ -40,6 +40,8 @@ private: { } + static RefPtr<ProcessGroup> from_pgid_nolock(ProcessGroupID); + ProcessGroup* m_prev { nullptr }; ProcessGroup* m_next { nullptr }; |