[haiku-bugs] Re: [Haiku] #5816: Kernel out of memory
- From: "bonefish" <trac@xxxxxxxxxxxx>
- Date: Thu, 17 Jun 2010 12:21:05 -0000
#5816: Kernel out of memory
---------------------------+------------------------------------------------
Reporter: axeld | Owner: bonefish
Type: bug | Status: assigned
Priority: normal | Milestone: R1/alpha3
Component: System/Kernel | Version: R1/Development
Keywords: | Blockedby:
Patch: 0 | Platform: All
Blocking: 4963 |
---------------------------+------------------------------------------------
Comment(by bonefish):
Some additional output in object_cache_low_memory() makes it clear what is
happening:
{{{
low resource address space: normal -> note
object_cache_low_memory(): cache 0x82808d00: pressure: 356, empty: 0
object_cache_low_memory(): cache 0x828a1dc0: pressure: 397, empty: 2
object_cache_low_memory(): cache 0x828a6140: pressure: 2449, empty: 0
block_cache::_LowMemoryHandler(): 0xd1526000: unused: 10 -> 10
block_cache::_LowMemoryHandler(): 0x83023594: unused: 3 -> 0
block_cache::_LowMemoryHandler(): 0xd1526594: unused: 313434 -> 313384
block_cache::_LowMemoryHandler(): 0xd0921198: unused: 13 -> 0
object_cache_low_memory(): cache 0x82808d00: pressure: 356, empty: 0
object_cache_low_memory(): cache 0x828a1dc0: pressure: 397, empty: 9
object_cache_low_memory(): cache 0x828a6140: pressure: 2449, empty: 0
block_cache::_LowMemoryHandler(): 0xd1526000: unused: 3156 -> 3156
block_cache::_LowMemoryHandler(): 0x83023594: unused: 0 -> 0
block_cache::_LowMemoryHandler(): 0xd1526594: unused: 313054 -> 313004
block_cache::_LowMemoryHandler(): 0xd0921198: unused: 0 -> 0
object_cache_low_memory(): cache 0x82808d00: pressure: 356, empty: 3
object_cache_low_memory(): cache 0x828a1dc0: pressure: 397, empty: 141
object_cache_low_memory(): cache 0x828a6140: pressure: 2449, empty: 0
block_cache::_LowMemoryHandler(): 0xd1526000: unused: 0 -> 0
block_cache::_LowMemoryHandler(): 0x83023594: unused: 0 -> 0
block_cache::_LowMemoryHandler(): 0xd1526594: unused: 312768 -> 312718
block_cache::_LowMemoryHandler(): 0xd0921198: unused: 0 -> 0
}}}
`ObjectCache::pressure` is only decreased when the low resource level
reaches at least "warning" (which never happens during the test), so the
empty slab counts have a fixed upper limit (e.g. 1225 for the source
volume block cache).
Reviewing the figures from the previous run, the slabs use less than 800
MB, BTW. Fragmentation of the slab areas might translate that to quite a
bit more, but I guess the real problem is that the heap is continuously
growing -- i.e. even if the slabs were drained completely, the address
space limit would be hit eventually. It also doesn't help that heap and
slab have different allocation backends (IOW that the slab allocator is
not used as the heap).
--
Ticket URL: <http://dev.haiku-os.org/ticket/5816#comment:8>
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