FD table now holds both VFS1 and VFS2 types and uses the correct
one based on what's set.
Parts of this CL are just initial changes (e.g. sys_read.go,
runsc/main.go) to serve as a template for the remaining changes.
Updates #1487
Updates #1623
PiperOrigin-RevId: 292023223
This renames FDMap to FDTable and drops the kernel.FD type, which had an entire
package to itself and didn't serve much use (it was freely cast between types,
and served as more of an annoyance than providing any protection.)
Based on BenchmarkFDLookupAndDecRef-12, we can expect 5-10 ns per lookup
operation, and 10-15 ns per concurrent lookup operation of savings.
This also fixes two tangential usage issues with the FDMap. Namely, non-atomic
use of NewFDFrom and associated calls to Remove (that are both racy and fail to
drop the reference on the underlying file.)
PiperOrigin-RevId: 256285890
We don't actually support core dumps, but some applications want to
get/set dumpability, which still has an effect in procfs.
Lack of support for set-uid binaries or fs creds simplifies things a
bit.
As-is, processes started via CreateProcess (i.e., init and sentryctl
exec) have normal dumpability. I'm a bit torn on whether sentryctl exec
tasks should be dumpable, but at least since they have no parent normal
UID/GID checks should protect them.
PiperOrigin-RevId: 251712714
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
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
This allows us to call kernel.FDMap.DecRef without holding mutexes
cleanly.
PiperOrigin-RevId: 211139657
Change-Id: Ie59d5210fb9282e1950e2e40323df7264a01bcec
Fabricio Voznika
Michael Pratt
Adin Scannell
Nicolas Lacasse
Ian Gudger
Jamie Liu
Zhaozhong Ni
Googler