[haiku-bugs] Re: [Haiku] #5816: Kernel out of memory
- From: "bonefish" <trac@xxxxxxxxxxxx>
- Date: Wed, 16 Jun 2010 20:43:24 -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: |
---------------------------+------------------------------------------------
Changes (by bonefish):
* owner: axeld => bonefish
* status: new => assigned
Comment:
I've also run into this during the last few days while testing PAE on a
box with 4 GB RAM. After a `dd if=/dev/zero of=tt bs=1M count=3500` I
started copying two haiku trees (with objects, weighing in at about 3.6
GB) from one partition to another. The copy process started relatively
slow -- 2 to 3 MB/s -- and after a while dropped to abysmally slow -- <
100 KB/s. I didn't always let the copy process run on, but twice I let it
run until it hit the out of memory panic. The syslog said pretty much the
same as in the previous comment: The slab and heap would grow until the
heap grower failed to allocate new areas. The reason being lack of address
space in my case and apparently in the above one, too.
As can be seen in the output, the slab allocations stop at some point --
probably when the address space low resource state reaches "note" and the
block cache stops allocated new blocks -- and only the heap continues to
grow -- probably for vnodes and related structures. That is suboptimal
already -- currently the kernel favors vnodes over block cache over file
cache. Still it doesn't explain why slab areas aren't freed at some point.
At low resource state "critical" the block cache should go all out and
throw away lots of blocks. Also, that doesn't explain the amazingly poor
copying performance.
Will try to analyze a bit.
--
Ticket URL: <http://dev.haiku-os.org/ticket/5816#comment:3>
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