Kernel: /proc/{pid}/meminfo now reports per process memory usage

kernel/kernel/FS/ProcFS/Inode.cpp

@@ -23,4 +23,36 @@ namespace Kernel
 	{
 	}
 
+	BAN::ErrorOr<BAN::RefPtr<ProcMemInode>> ProcMemInode::create(Process& process, RamFileSystem& fs, mode_t mode, uid_t uid, gid_t gid)
+	{
+		FullInodeInfo inode_info(fs, mode, uid, gid);
+
+		auto* inode_ptr = new ProcMemInode(process, fs, inode_info);
+		if (inode_ptr == nullptr)
+			return BAN::Error::from_errno(ENOMEM);
+		return BAN::RefPtr<ProcMemInode>::adopt(inode_ptr);
+	}
+
+	ProcMemInode::ProcMemInode(Process& process, RamFileSystem& fs, const FullInodeInfo& inode_info)
+		: RamInode(fs, inode_info)
+		, m_process(process)
+	{
+		m_inode_info.mode |= Inode::Mode::IFREG;
+	}
+
+	BAN::ErrorOr<size_t> ProcMemInode::read_impl(off_t offset, void* buffer, size_t buffer_size)
+	{
+		ASSERT(offset >= 0);
+		if ((size_t)offset >= sizeof(proc_meminfo_t))
+			return 0;
+
+		proc_meminfo_t meminfo;
+		m_process.get_meminfo(&meminfo);
+
+		size_t bytes = BAN::Math::min<size_t>(buffer_size, sizeof(meminfo) - offset);
+		memcpy(buffer, &meminfo, bytes);
+		
+		return bytes;
+	}
+
 }

kernel/kernel/Process.cpp

@@ -252,6 +252,21 @@ namespace Kernel
 			thread->set_terminating();
 	}
 
+	void Process::get_meminfo(proc_meminfo_t* out) const
+	{
+		LockGuard _(m_lock);
+
+		out->page_size = PAGE_SIZE;
+
+		out->virt_pages = 0;
+		for (auto* thread : m_threads)
+			out->virt_pages += thread->virtual_page_count();
+		for (auto& region : m_mapped_regions)
+			out->virt_pages += region->virtual_page_count();
+		if (m_loadable_elf)
+			out->virt_pages += m_loadable_elf->virtual_page_count();
+	}
+
 	BAN::ErrorOr<long> Process::sys_exit(int status)
 	{
 		exit(status, 0);