This feature allows MemoryFile to delay eviction of "optional"
allocations, such as unused cached file pages.
Note that this incidentally makes CachingInodeOperations writeback
asynchronous, in the sense that it doesn't occur until eviction; this is
necessary because between when a cached page becomes evictable and when
it's evicted, file writes (via CachingInodeOperations.Write) may dirty
the page.
As currently implemented, this feature won't meaningfully impact
steady-state memory usage or caching; the reclaimer goroutine will
schedule eviction as soon as it runs out of other work to do. Future CLs
increase caching by adding constraints on when eviction is scheduled.
PiperOrigin-RevId: 246014822
Change-Id: Ia85feb25a2de92a48359eb84434b6ec6f9bea2cb
Based on the guidelines at
https://opensource.google.com/docs/releasing/authors/.
1. $ rg -l "Google LLC" | xargs sed -i 's/Google LLC.*/The gVisor Authors./'
2. Manual fixup of "Google Inc" references.
3. Add AUTHORS file. Authors may request to be added to this file.
4. Point netstack AUTHORS to gVisor AUTHORS. Drop CONTRIBUTORS.
Fixes#209
PiperOrigin-RevId: 245823212
Change-Id: I64530b24ad021a7d683137459cafc510f5ee1de9
The existing logic attempting to do this is incorrect. Unary ^ has
higher precedence than &^, so mask always has UnblockableSignals
cleared, allowing dequeueSignalLocked to dequeue unblockable signals
(which allows userspace to ignore them).
Switch the logic so that unblockable signals are always masked.
PiperOrigin-RevId: 244058487
Change-Id: Ib19630ac04068a1fbfb9dc4a8eab1ccbdb21edc3
FD limit and file size limit is read from the host, instead
of using hard-coded defaults, given that they effect the sandbox
process. Also limit the direct cache to use no more than half
if the available FDs.
PiperOrigin-RevId: 244050323
Change-Id: I787ad0fdf07c49d589e51aebfeae477324fe26e6
RootFromContext can return a dirent with reference taken, or nil. We must call
DecRef if (and only if) a real dirent is returned.
PiperOrigin-RevId: 242965515
Change-Id: Ie2b7b4cb19ee09b6ccf788b71f3fd7efcdf35a11
DirentCache is already a savable type, and it ensures that it is empty at the
point of Save. There is no reason not to save it along with the MountSource.
This did uncover an issue where not all MountSources were properly flushed
before Save. If a mount point has an open file and is then unmounted, we save
the MountSource without flushing it first. This CL also fixes that by flushing
all MountSources for all open FDs on Save.
PiperOrigin-RevId: 242906637
Change-Id: I3acd9d52b6ce6b8c989f835a408016cb3e67018f
From sendfile spec and also the linux kernel code, we should
limit the count arg to 'MAX_RW_COUNT'. This patch export
'MAX_RW_COUNT' in kernel pkg and use it in the implementation
of sendfile syscall.
Signed-off-by: Li Qiang <pangpei.lq@antfin.com>
Change-Id: I1086fec0685587116984555abd22b07ac233fbd2
PiperOrigin-RevId: 242745831
In particular, ns.IDOfTask and tg.ID are used for gettid and getpid,
respectively, where removing defer saves ~100ns. This may be a small
improvement to application logging, which may call gettid/getpid
frequently.
PiperOrigin-RevId: 242039616
Change-Id: I860beb62db3fe077519835e6bafa7c74cba6ca80
This will save copies when preemption is not caused by a CPU migration.
PiperOrigin-RevId: 241844399
Change-Id: I2ba3b64aa377846ab763425bd59b61158f576851
If there are thousands of threads, ThreadGroupsAppend becomes very
expensive as it must iterate over all Tasks to find the ThreadGroup
leaders.
Reduce the cost by maintaining a map of ThreadGroups which can be used
to grab them all directly.
The one somewhat visible change is to convert PID namespace init
children zapping to a group-directed SIGKILL, as Linux did in
82058d668465 "signal: Use group_send_sig_info to kill all processes in a
pid namespace".
In a benchmark that creates N threads which sleep for two minutes, we
see approximately this much CPU time in ThreadGroupsAppend:
Before:
1 thread: 0ms
1024 threads: 30ms - 9130ms
4096 threads: 50ms - 2000ms
8192 threads: 18160ms
16384 threads: 17210ms
After:
1 thread: 0ms
1024 threads: 0ms
4096 threads: 0ms
8192 threads: 0ms
16384 threads: 0ms
The profiling is actually extremely noisy (likely due to cache effects),
as some runs show almost no samples at 1024, 4096 threads, but obviously
this does not scale to lots of threads.
PiperOrigin-RevId: 241828039
Change-Id: I17827c90045df4b3c49b3174f3a05bca3026a72c
We weren't saving simple devices' last allocated inode numbers, which
caused inode number reuse across S/R.
PiperOrigin-RevId: 241414245
Change-Id: I964289978841ef0a57d2fa48daf8eab7633c1284
ilist:generic_list works faster (cl/240185278) and
the code looks cleaner without type casting.
PiperOrigin-RevId: 241381175
Change-Id: I8487ab1d73637b3e9733c253c56dce9e79f0d35f
When fork a child process, the name filed of TaskContext is not set.
It results in that when we cat /proc/{pid}/status, the name filed is
null.
Like this:
Name:
State: S (sleeping)
Tgid: 28
Pid: 28
PPid: 26
TracerPid: 0
FDSize: 8
VmSize: 89712 kB
VmRSS: 6648 kB
Threads: 1
CapInh: 00000000a93d35fb
CapPrm: 0000000000000000
CapEff: 0000000000000000
CapBnd: 00000000a93d35fb
Seccomp: 0
Change-Id: I5d469098c37cedd19da16b7ffab2e546a28a321e
PiperOrigin-RevId: 240893304
MM.insertPMAsLocked() passes vma.maxPerms to memmap.Mappable.Translate
(although it unsets AccessType.Write if the vma is private). This
somewhat simplifies handling of pmas, since it means only COW-break
needs to replace existing pmas. However, it also means that a MAP_SHARED
mapping of a file opened O_RDWR dirties the file, regardless of the
mapping's permissions and whether or not the mapping is ever actually
written to with I/O that ignores permissions (e.g.
ptrace(PTRACE_POKEDATA)).
To fix this:
- Change the pma-getting path to request only the permissions that are
required for the calling access.
- Change memmap.Mappable.Translate to take requested permissions, and
return allowed permissions. This preserves the existing behavior in the
common cases where the memmap.Mappable isn't
fsutil.CachingInodeOperations and doesn't care if the translated
platform.File pages are written to.
- Change the MM.getPMAsLocked path to support permission upgrading of
pmas outside of copy-on-write.
PiperOrigin-RevId: 240196979
Change-Id: Ie0147c62c1fbc409467a6fa16269a413f3d7d571
ilist:generic_list works faster than ilist:ilist.
Here is a beanchmark test to measure performance of epoll_wait, when readyList
isn't empty. It shows about 30% better performance with these changes.
Benchmark Time(ns) CPU(ns) Iterations
Before:
BM_EpollAllEvents 46725 46899 14286
After:
BM_EpollAllEvents 33167 33300 18919
PiperOrigin-RevId: 240185278
Change-Id: I3e33f9b214db13ab840b91613400525de5b58d18
A credential object is immutable, so we don't need to copy it for a new
task.
PiperOrigin-RevId: 239519266
Change-Id: I0632f641fdea9554779ac25d84bee4231d0d18f2
This is in preparation for improved page cache reclaim, which requires
greater integration between the page cache and page allocator.
PiperOrigin-RevId: 238444706
Change-Id: Id24141b3678d96c7d7dc24baddd9be555bffafe4
It is Implemented without the priority inheritance part given
that gVisor defers scheduling decisions to Go runtime and doesn't
have control over it.
PiperOrigin-RevId: 236989545
Change-Id: I714c8ca0798743ecf3167b14ffeb5cd834302560
- Use new user namespace for namespace creation checks.
- Ensure userns is never nil since it's used by other namespaces.
PiperOrigin-RevId: 234673175
Change-Id: I4b9d9d1e63ce4e24362089793961a996f7540cd9
If a background process tries to read from a TTY, linux sends it a SIGTTIN
unless the signal is blocked or ignored, or the process group is an orphan, in
which case the syscall returns EIO.
See drivers/tty/n_tty.c:n_tty_read()=>job_control().
If a background process tries to write a TTY, set the termios, or set the
foreground process group, linux then sends a SIGTTOU. If the signal is ignored
or blocked, linux allows the write. If the process group is an orphan, the
syscall returns EIO.
See drivers/tty/tty_io.c:tty_check_change().
PiperOrigin-RevId: 234044367
Change-Id: I009461352ac4f3f11c5d42c43ac36bb0caa580f9
Nothing reads them and they can simply get stale.
Generated with:
$ sed -i "s/licenses(\(.*\)).*/licenses(\1)/" **/BUILD
PiperOrigin-RevId: 231818945
Change-Id: Ibc3f9838546b7e94f13f217060d31f4ada9d4bf0
More helper structs have been added to the fsutil package to make it easier to
implement fs.InodeOperations and fs.FileOperations.
PiperOrigin-RevId: 229305982
Change-Id: Ib6f8d3862f4216745116857913dbfa351530223b
- Call MemoryEvents.done.Add(1) outside of MemoryEvents.run() so that if
MemoryEvents.Stop() => MemoryEvents.done.Wait() is called before the
goroutine starts running, it still waits for the goroutine to stop.
- Use defer to call MemoryEvents.done.Done() in MemoryEvents.run() so that it's
called even if the goroutine panics.
PiperOrigin-RevId: 228623307
Change-Id: I1b0459e7999606c1a1a271b16092b1ca87005015
See modified comment in auth.NewUserCredentials(); compare to the
behavior of setresuid(2) as implemented by
//pkg/sentry/kernel/task_identity.go:kernel.Task.setKUIDsUncheckedLocked().
PiperOrigin-RevId: 228381765
Change-Id: I45238777c8f63fcf41b99fce3969caaf682fe408
Jamie Liu
Fabricio Voznika
Michael Pratt
Nicolas Lacasse
Kevin Krakauer
Li Qiang
Rahat Mahmood
Andrei Vagin
chris.zn
Haibo Xu
Brian Geffon
Adin Scannell