RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-05-23 18:15:06 +00:00
Code Issues Activity Actions

Kernel: Make purgeable memory a VMObject level concept (again)

Browse source 
This patch changes the semantics of purgeable memory.

- AnonymousVMObject now has a "purgeable" flag. It can only be set when
  constructing the object. (Previously, all anonymous memory was
  effectively purgeable.)

- AnonymousVMObject now has a "volatile" flag. It covers the entire
  range of physical pages. (Previously, we tracked ranges of volatile
  pages, effectively making it a page-level concept.)

- Non-volatile objects maintain a physical page reservation via the
  committed pages mechanism, to ensure full coverage for page faults.

- When an object is made volatile, it relinquishes any unused committed
  pages immediately. If later made non-volatile again, we then attempt
  to make a new committed pages reservation. If this fails, we return
  ENOMEM to userspace.

mmap() now creates purgeable objects if passed the MAP_PURGEABLE option
together with MAP_ANONYMOUS. anon_create() memory is always purgeable.
This commit is contained in:
Andreas Kling 2021-07-25 01:46:44 +02:00
parent 6bb53d6a80
commit 2d1a651e0a
17 changed files with 189 additions and 1004 deletions
Download patch file Download diff file Expand all files Collapse all files

2
Kernel/ProcessSpecificExposed.cpp
View file

@ -456,7 +456,7 @@ private:
region_object.add("syscall", region->is_syscall_region());
region_object.add("purgeable", region->vmobject().is_anonymous());
if (region->vmobject().is_anonymous()) {
region_object.add("volatile", static_cast<const AnonymousVMObject&>(region->vmobject()).is_any_volatile());
region_object.add("volatile", static_cast<AnonymousVMObject const&>(region->vmobject()).is_volatile());
}
region_object.add("cacheable", region->is_cacheable());
region_object.add("address", region->vaddr().get());