MemoryFile allocated offsets from the top down. This can generate
fragmentation when allocations happen in the opposite direction.
Given that applications control the order of allocations, use simple
heuristics to track the last faulted address to determine whether memory
file should be allocated from the top-down or bottom-up.
Here is the number of PMAs used across all processes in some common
workloads:
Workload | Before | After | Diff
---------|---------|---------|------
rustc | 135,269 | 1,090 | 0.8%
mysql | 16,466 | 4,576 | 28%
nginx | 1,738 | 1,609 | 93%
jenkins | 13,830 | 6,380 | 46%
redis | 334 | 308 | 92%
absl | 297,419 | 292,121 | 98%
Here is the direction of PMA allocations:
Workload | BottomUp | TopDown |
---------|-----------|---------|
mysql | 13,849 | 1,990 |
nginx | 783 | 628 |
jenkins | 13,922 | 2,333 |
redis | 88 | 109 |
absl | 212,403 | 44,019 |
Tests were done on Intel x64.
PiperOrigin-RevId: 409014690
Split usermem package to help remove syserror dependency in go_marshal.
New hostarch package contains code not dependent on syserror.
PiperOrigin-RevId: 365651233
This change has multiple small components.
First, the chunk size is bumped to 1GB in order to avoid creating excessive
VMAs in the Sentry, which can lead to VMA exhaustion (and hitting limits).
Second, gap-tracking is added to the usage set in order to efficiently scan
for available regions.
Third, reclaim is moved to a simple segment set. This is done to allow the
order of reclaim to align with the Allocate order (which becomes much more
complex when trying to track a "max page" as opposed to "min page", so we
just track explicit segments instead, which should make reclaim scanning
faster anyways).
Finally, the findAvailable function attempts to scan from the top-down, in
order to maximize opportunities for VMA merging in applications (hopefully
preventing the same VMA exhaustion that can affect the Sentry).
PiperOrigin-RevId: 315009249
Because the abi will depend on the core types for marshalling (usermem,
context, safemem, safecopy), these need to be flattened from the sentry
directory. These packages contain no sentry-specific details.
PiperOrigin-RevId: 291811289
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
