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Kernel: Don't copy a Vector<FileDescriptionAndFlags>

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Instead of copying a Vector everytime we need to enumerate a Process'
file descriptions, we can just temporarily lock so it won't change.
This commit is contained in:
Liav A 2021-06-22 21:22:17 +03:00 • committed by Andreas Kling
parent 12b6e69150
commit 7c87891c06
28 changed files with 198 additions and 128 deletions
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74
Kernel/Process.h
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@ -228,9 +228,6 @@ public:
bool in_group(gid_t) const;
RefPtr<FileDescription> file_description(int fd) const;
int fd_flags(int fd) const;
// Breakable iteration functions
template<IteratorFunction<Process&> Callback>
static void for_each(Callback);
@ -443,12 +440,6 @@ public:
const Vector<String>& arguments() const { return m_arguments; };
const Vector<String>& environment() const { return m_environment; };
int number_of_open_file_descriptors() const;
int max_open_file_descriptors() const
{
return m_max_open_file_descriptors;
}
KResult exec(String path, Vector<String> arguments, Vector<String> environment, int recusion_depth = 0);
KResultOr<LoadResult> load(NonnullRefPtr<FileDescription> main_program_description, RefPtr<FileDescription> interpreter_description, const ElfW(Ehdr) & main_program_header);
@ -541,8 +532,6 @@ private:
KResultOr<RefPtr<FileDescription>> find_elf_interpreter_for_executable(const String& path, const ElfW(Ehdr) & elf_header, int nread, size_t file_size);
int alloc_fd(int first_candidate_fd = 0);
KResult do_kill(Process&, int signal);
KResult do_killpg(ProcessGroupID pgrp, int signal);
KResult do_killall(int signal);
@ -586,8 +575,6 @@ private:
OwnPtr<ThreadTracer> m_tracer;
static constexpr int m_max_open_file_descriptors { FD_SETSIZE };
public:
class FileDescriptionAndFlags {
friend class FileDescriptionRegistrar;
@ -616,14 +603,62 @@ public:
InodeIndex m_global_procfs_inode_index;
};
// FIXME: We create a copy when trying to iterate the Vector because
// we don't want to put lots of locking when accessing this Vector.
// Maybe try to encapsulate the Vector inside a protective class with locking
// mechanism.
Vector<FileDescriptionAndFlags> fds() const { return m_fds; }
class FileDescriptions {
friend class Process;
public:
ALWAYS_INLINE const FileDescriptionAndFlags& operator[](size_t i) const { return at(i); }
ALWAYS_INLINE FileDescriptionAndFlags& operator[](size_t i) { return at(i); }
FileDescriptions& operator=(const Kernel::Process::FileDescriptions& other)
{
ScopedSpinLock lock(m_fds_lock);
ScopedSpinLock lock_other(other.m_fds_lock);
m_fds_metadatas = other.m_fds_metadatas;
for (auto& file_description_metadata : m_fds_metadatas) {
file_description_metadata.refresh_inode_index();
}
return *this;
}
const FileDescriptionAndFlags& at(size_t i) const;
FileDescriptionAndFlags& at(size_t i);
void enumerate(Function<void(const FileDescriptionAndFlags&)>) const;
void change_each(Function<void(FileDescriptionAndFlags&)>);
int allocate(int first_candidate_fd = 0);
size_t open_count() const;
bool try_resize(size_t size) { return m_fds_metadatas.try_resize(size); }
size_t max_open() const
{
return m_max_open_file_descriptors;
}
void clear()
{
ScopedSpinLock lock(m_fds_lock);
m_fds_metadatas.clear();
}
// FIXME: Consider to remove this somehow
RefPtr<FileDescription> file_description(int fd) const;
int fd_flags(int fd) const;
private:
FileDescriptions() = default;
static constexpr size_t m_max_open_file_descriptors { FD_SETSIZE };
mutable SpinLock<u8> m_fds_lock;
Vector<FileDescriptionAndFlags> m_fds_metadatas;
};
FileDescriptions& fds() { return m_fds; }
const FileDescriptions& fds() const { return m_fds; }
private:
Vector<FileDescriptionAndFlags> m_fds;
FileDescriptions m_fds;
mutable RecursiveSpinLock m_thread_list_lock;
@ -659,7 +694,6 @@ private:
FutexQueues m_futex_queues;
SpinLock<u8> m_futex_lock;
mutable SpinLock<u8> m_fds_lock;
// This member is used in the implementation of ptrace's PT_TRACEME flag.
// If it is set to true, the process will stop at the next execve syscall