When a pages file is provided to `runsc restore`, reads from that file are
asynchronous (via statefile.AsyncReader) in order to maximize throughput.
However, all such reads must complete before Kernel.LoadFrom() returns, so
applications cannot execute before MemoryFile loading is complete. The main
objective of this CL is to allow reads to continue after Kernel.LoadFrom()
returns, allowing applications to execute while MemoryFile loading is still in
progress. This behavior is user-visible: it affects whether deleting the pages
file frees disk space immediately on POSIX filesystems, may affect whether
deletion is possible on non-POSIX filesystems, and prevents unmounting
regardless. Thus it is flag-guarded as `runsc restore --background`.
MemoryFile ranges that have yet to be loaded, but that are being waited-for by
applications, should be prioritized over ranges for which no application is
waiting. This requires that application requests for data (calls to
MemoryFile.(memmap.File).DataFD/MapInternal()) are able to determine which
ranges have not yet been loaded, request reads for such ranges with elevated
priority, and wait for only those reads to be completed; none of these are
supported by the existing statefile.AsyncReader.
Thus:
- Add //pkg/sentry/pgalloc/aio, which provides an async I/O API that is
designed to be easily implementable using a goroutine pool, Linux native AIO,
or io_uring, though only includes a goroutine pool implementation. (io_uring
is widely disabled due to security vulnerabilities. In my testing, Linux
native AIO is slower than the goroutine pool, but this may change with lower
GOMAXPROCS which needs further testing.)
- Move I/O scheduling into pgalloc: introduce an async page loader goroutine
that is started by MemoryFile.LoadFrom() when async page loading is requested
(implicitly, via the existence of a pages file), which is responsible for
driving submission of read requests and handling their completions.
PiperOrigin-RevId: 679321884
- Adds a new flag which will enable netstack s/r. When the flag is not enabled,
there is no change in the existing behavior. The flag will be enabled only in
tests to verify the s/r functionality of netstack.
- Some additional fields in netstack were causing panic when netstack is
save/restored. Such fields are marked as 'save'/'nosave' accordingly to resolve
the panic.
PiperOrigin-RevId: 668566657
This option, enabled via `runsc checkpoint --exclude-committed-zero-pages`,
instructs `pgalloc.MemoryFile.SaveTo()` to also exclude definitely-committed
zero pages from checkpointing (in addition to possibly-committed zero pages,
which are always scanned for and excluded). This is useful when the application
being checkpointed is known to have a large number of committed zero pages:
pages that (1) have been touched by application memory accesses, a syscall such
as read(), or page pinning by e.g. a driver, and (2) have not been subsequently
released by the application to the operating system by e.g. munmap() or
madvise(MADV_DONTNEED) (+ page unpinning if necessary), and (3) are filled with
zero bytes.
Minor changes:
- In `MemoryFile.updateUsageLocked()`, pass file offset to `checkCommitted` so
that `MemoryFile.SaveTo()`'s `checkCommitted` can use `FALLOC_FL_PUNCH_HOLE`
to decommit pages rather than `MADV_REMOVE` (which translates addresses to
file offsets and then invokes `FALLOC_FL_PUNCH_HOLE`).
- In `MemoryFile.SaveTo()`, buffer up to a hugepage worth of pages to decommit
rather than decommitting one page per syscall.
- Increment `MemoryFile.usageExpected` in `MemoryFile.LoadFrom()`, such that
the first following call to `MemoryFile.UpdateUsage()` might skip the call
to `MemoryFile.updateUsageLocked()` (if memory usage hasn't changed since
loading).
PiperOrigin-RevId: 632370455
This makes the code in controller.go simple, especially
for multi-container restore that requires taking ownership
of files.
PiperOrigin-RevId: 627165958
Adds the save-resume variant to all syscall tests. These tests save/checkpoint
the sandbox for every syscall in the test and then resume.
PiperOrigin-RevId: 623601440
Starting with Go 1.21, build tags select the language version. We currently
have several `go:build go1.1` tags, which were intended to act as "true" tags.
But that will break with 1.21. So replace them with "!false".
Fixes#9568.
PiperOrigin-RevId: 576020779
Add Equals method to compare syserror and unix.Errno errors to linuxerr errors.
This will facilitate removal of syserror definitions in a followup, and
finding needed conversions from unix.Errno to linuxerr.
PiperOrigin-RevId: 380909667
The syscall package has been deprecated in favor of golang.org/x/sys.
Note that syscall is still used in the following places:
- pkg/sentry/socket/hostinet/stack.go: some netlink related functionalities
are not yet available in golang.org/x/sys.
- syscall.Stat_t is still used in some places because os.FileInfo.Sys() still
returns it and not unix.Stat_t.
Updates #214
PiperOrigin-RevId: 360701387
Inode number consistency checks are now skipped in save/restore tests for
reasons described in greatest detail in StatTest.StateDoesntChangeAfterRename.
They pass in VFS1 due to the bug described in new test case
SimpleStatTest.DifferentFilesHaveDifferentDeviceInodeNumberPairs.
Fixes#1663
PiperOrigin-RevId: 338776148
Endpoint protocol goroutines were previously started as part of
loading the endpoint. This is potentially too soon, as resources used
by these goroutine may not have been loaded. Protocol goroutines may
perform meaningful work as soon as they're started (ex: incoming
connect) which can cause them to indirectly access resources that
haven't been loaded yet.
This CL defers resuming all protocol goroutines until the end of
restore.
PiperOrigin-RevId: 262409429
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
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
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