diff options
| -rw-r--r-- | pkg/sentry/fs/proc/meminfo.go | 10 | ||||
| -rw-r--r-- | pkg/sentry/fsimpl/proc/tasks_files.go | 10 | ||||
| -rw-r--r-- | pkg/sentry/syscalls/linux/sys_sysinfo.go | 7 | ||||
| -rw-r--r-- | pkg/sentry/usage/memory.go | 24 |
4 files changed, 36 insertions, 15 deletions
diff --git a/pkg/sentry/fs/proc/meminfo.go b/pkg/sentry/fs/proc/meminfo.go index 465b47da9..91617267d 100644 --- a/pkg/sentry/fs/proc/meminfo.go +++ b/pkg/sentry/fs/proc/meminfo.go @@ -58,12 +58,16 @@ func (d *meminfoData) ReadSeqFileData(ctx context.Context, h seqfile.SeqHandle) var buf bytes.Buffer fmt.Fprintf(&buf, "MemTotal: %8d kB\n", totalSize/1024) - memFree := (totalSize - totalUsage) / 1024 + memFree := totalSize - totalUsage + if memFree > totalSize { + // Underflow. + memFree = 0 + } // We use MemFree as MemAvailable because we don't swap. // TODO(rahat): When reclaim is implemented the value of MemAvailable // should change. - fmt.Fprintf(&buf, "MemFree: %8d kB\n", memFree) - fmt.Fprintf(&buf, "MemAvailable: %8d kB\n", memFree) + fmt.Fprintf(&buf, "MemFree: %8d kB\n", memFree/1024) + fmt.Fprintf(&buf, "MemAvailable: %8d kB\n", memFree/1024) fmt.Fprintf(&buf, "Buffers: 0 kB\n") // memory usage by block devices fmt.Fprintf(&buf, "Cached: %8d kB\n", (file+snapshot.Tmpfs)/1024) // Emulate a system with no swap, which disables inactivation of anon pages. diff --git a/pkg/sentry/fsimpl/proc/tasks_files.go b/pkg/sentry/fsimpl/proc/tasks_files.go index 92007df81..e5f13b69e 100644 --- a/pkg/sentry/fsimpl/proc/tasks_files.go +++ b/pkg/sentry/fsimpl/proc/tasks_files.go @@ -272,12 +272,16 @@ func (*meminfoData) Generate(ctx context.Context, buf *bytes.Buffer) error { inactiveFile := file - activeFile fmt.Fprintf(buf, "MemTotal: %8d kB\n", totalSize/1024) - memFree := (totalSize - totalUsage) / 1024 + memFree := totalSize - totalUsage + if memFree > totalSize { + // Underflow. + memFree = 0 + } // We use MemFree as MemAvailable because we don't swap. // TODO(rahat): When reclaim is implemented the value of MemAvailable // should change. - fmt.Fprintf(buf, "MemFree: %8d kB\n", memFree) - fmt.Fprintf(buf, "MemAvailable: %8d kB\n", memFree) + fmt.Fprintf(buf, "MemFree: %8d kB\n", memFree/1024) + fmt.Fprintf(buf, "MemAvailable: %8d kB\n", memFree/1024) fmt.Fprintf(buf, "Buffers: 0 kB\n") // memory usage by block devices fmt.Fprintf(buf, "Cached: %8d kB\n", (file+snapshot.Tmpfs)/1024) // Emulate a system with no swap, which disables inactivation of anon pages. diff --git a/pkg/sentry/syscalls/linux/sys_sysinfo.go b/pkg/sentry/syscalls/linux/sys_sysinfo.go index a65b560c8..297de052a 100644 --- a/pkg/sentry/syscalls/linux/sys_sysinfo.go +++ b/pkg/sentry/syscalls/linux/sys_sysinfo.go @@ -29,13 +29,18 @@ func Sysinfo(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysca mf.UpdateUsage() _, totalUsage := usage.MemoryAccounting.Copy() totalSize := usage.TotalMemory(mf.TotalSize(), totalUsage) + memFree := totalSize - totalUsage + if memFree > totalSize { + // Underflow. + memFree = 0 + } // Only a subset of the fields in sysinfo_t make sense to return. si := linux.Sysinfo{ Procs: uint16(len(t.PIDNamespace().Tasks())), Uptime: t.Kernel().MonotonicClock().Now().Seconds(), TotalRAM: totalSize, - FreeRAM: totalSize - totalUsage, + FreeRAM: memFree, Unit: 1, } _, err := t.CopyOut(addr, si) diff --git a/pkg/sentry/usage/memory.go b/pkg/sentry/usage/memory.go index 4320ad17f..ab1d140d2 100644 --- a/pkg/sentry/usage/memory.go +++ b/pkg/sentry/usage/memory.go @@ -252,18 +252,23 @@ func (m *MemoryLocked) Copy() (MemoryStats, uint64) { return ms, m.totalLocked() } -// MinimumTotalMemoryBytes is the minimum reported total system memory. -// -// This can be configured through options provided to the Sentry at start. -// This number is purely synthetic. This is only set before the application -// starts executing, and must not be modified. -var MinimumTotalMemoryBytes uint64 = 2 << 30 // 2 GB +// These options control how much total memory the is reported to the application. +// They may only be set before the application starts executing, and must not +// be modified. +var ( + // MinimumTotalMemoryBytes is the minimum reported total system memory. + MinimumTotalMemoryBytes uint64 = 2 << 30 // 2 GB + + // MaximumTotalMemoryBytes is the maximum reported total system memory. + // The 0 value indicates no maximum. + MaximumTotalMemoryBytes uint64 +) // TotalMemory returns the "total usable memory" available. // // This number doesn't really have a true value so it's based on the following -// inputs and further bounded to be above some minimum guaranteed value (2GB), -// additionally ensuring that total memory reported is always less than used. +// inputs and further bounded to be above the MinumumTotalMemoryBytes and below +// MaximumTotalMemoryBytes. // // memSize should be the platform.Memory size reported by platform.Memory.TotalSize() // used is the total memory reported by MemoryLocked.Total() @@ -279,5 +284,8 @@ func TotalMemory(memSize, used uint64) uint64 { memSize = uint64(1) << (uint(msb) + 1) } } + if MaximumTotalMemoryBytes > 0 && memSize > MaximumTotalMemoryBytes { + memSize = MaximumTotalMemoryBytes + } return memSize } |