[haiku-bugs] [Haiku] #11221: Unify File System Caches
- From: "axeld" <trac@xxxxxxxxxxxx>
- Date: Wed, 10 Sep 2014 18:20:35 -0000
#11221: Unify File System Caches
---------------------------+------------------------------
Reporter: axeld | Owner: axeld
Type: enhancement | Status: new
Priority: normal | Milestone: Unscheduled
Component: System/Kernel | Version: R1/Development
Keywords: | Blocked By:
Blocking: | Has a Patch: 0
Platform: All |
---------------------------+------------------------------
The Haiku kernel provides two kinds of caches for use by file system
implementations: the file cache and the block cache. The file cache uses
physical memory pages directly and it is linked with the VM subsystem, so
that pages used for caching are freed automatically (in a least recently
used order) when running low on free memory. The block cache, however,
uses mapped memory (via the slab allocator) and freeing memory in low
memory situations is handled via the low resource manager. Using different
mechanisms to deal with low free memory situations leads to a caching
imbalance in favor of the block cache. Furthermore the block cache uses
large amounts of kernel address space, which can be problematic on 32 bit
architectures.
The goal is to create a common underlying mechanism (using `VMCache`) to
unify both caches. Solutions must be found to interesting problems like
how to deal with different block sizes (not necessarily matching the page
size) and how to map support for transactions to `VMCache` hierarchies
--
Ticket URL: <https://dev.haiku-os.org/ticket/11221>
Haiku <https://dev.haiku-os.org>
Haiku - the operating system.
Other related posts:
