class Evictor
Defined at line 35 of file ../../zircon/kernel/vm/include/vm/evictor.h
Implements page evictor logic to free pages belonging to a PmmNode under memory pressure.
Eviction in this context is both direct eviction of pager backed memory and discardable VMO
memory, as well as by performing compression.
This class is thread-safe.
Public Methods
Thread * DebugGetEvictorThread ()Debug method to retrieve any current eviction thread. Only to be used for testing / debugging
purposes. It is up to the caller to know if this objects is alive or not.
Defined at line 165 of file ../../zircon/kernel/vm/include/vm/evictor.h
void Evictor ()Defined at line 246 of file ../../zircon/kernel/vm/evictor.cc
void ~Evictor ()Defined at line 252 of file ../../zircon/kernel/vm/evictor.cc
void EnableEviction (bool use_compression)Called from the scanner to enable eviction if required. Creates an eviction thread to process
asynchronous eviction requests.
By default this only enables user pager based eviction and |use_compression| can be used to
also perform compression.
Defined at line 264 of file ../../zircon/kernel/vm/evictor.cc
void DisableEviction ()Called from the scanner to disable all eviction if needed, will shut down any in existing
eviction thread. It is a responsibility of the scanner to not have multiple concurrent calls
to this and EnableEviction.
Defined at line 287 of file ../../zircon/kernel/vm/evictor.cc
EvictionResult EvictFromExternalTarget (EvictionTarget target)Evict from a user specified external |target| which is only used for this eviction attempt and
does not interfere with the |eviction_target_|.
Defined at line 332 of file ../../zircon/kernel/vm/evictor.cc
EvictionResult EvictSynchronous (uint64_t min_mem_to_free, uint64_t free_mem_target, EvictionLevel eviction_level, Output output, TriggerReason reason)Performs a synchronous request to evict until free memory equals |free_mem_start| (in bytes)
and at least |min_mem_to_free| (in bytes) has been reclaimed. The return value is an
EvictionResult detailing exactly what was evicted and whether the free_mem_target was achieved.
The |eviction_level| is a rough control that maps to how old a page needs to be for being
considered for eviction. This may acquire arbitrary vmo and aspace locks.
Defined at line 409 of file ../../zircon/kernel/vm/evictor.cc
void EvictAsynchronous (uint64_t min_mem_to_free, uint64_t free_mem_target, EvictionLevel eviction_level, Output output)Reclaim memory until free memory equals the |free_mem_target| (in bytes) and at least
|min_mem_to_free| (in bytes) has been reclaimed. Reclamation will happen asynchronously on the
eviction thread and this function returns immediately. Once the target is reached, or there is
no more memory that can be reclaimed, this process will stop and the free memory target will be
cleared. The |eviction_level| is a rough control on how hard to try and evict. Multiple calls
to EvictAsynchronous will cause all the targets to get merged by adding together
|min_mem_to_free|, taking the max of |free_mem_target| and the highest or most aggressive of
any |eviction_level|.
Defined at line 429 of file ../../zircon/kernel/vm/evictor.cc
bool IsEvictionEnabled ()Whether any eviction can occur.
Defined at line 254 of file ../../zircon/kernel/vm/evictor.cc
bool IsCompressionEnabled ()Whether eviction should attempt to use compression.
Defined at line 259 of file ../../zircon/kernel/vm/evictor.cc
EvictorStats GetGlobalStats ()Return global eviction stats from all instantiations of the Evictor.
Defined at line 235 of file ../../zircon/kernel/vm/evictor.cc
Enumerations
enum EvictionLevel| Name | Value |
|---|---|
| OnlyOldest | 0 |
| IncludeNewest | 1 |
Defined at line 37 of file ../../zircon/kernel/vm/include/vm/evictor.h
enum Output| Name | Value |
|---|---|
| true | |
| NoPrint | false |
Defined at line 42 of file ../../zircon/kernel/vm/include/vm/evictor.h
enum TriggerReason| Name | Value |
|---|---|
| OOM | true |
| Other | false |
Defined at line 47 of file ../../zircon/kernel/vm/include/vm/evictor.h
Records
Friends
class TestPmmNode