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DescriptionAndrea Arcangeli
2011-06-10 01:19:00 UTC
Description of problem: nr_isolated_file of zone DMA becomes fixed 1 and nr_isolated_file or zone NORMAL becomes fixed -1
How reproducible: not reproducible with CONFIG_SMP=y, and so far only reproduced on x86 32bit (maybe because of lack of ZONE_DMA32 with <4GB of ram and HIGHMEM4G=y [64G=n]).
Steps to Reproduce:
1. run a lot of SLUB order 3 allocations or THP allocations invoking compaction (better on 32bit but THP isn't available on 32bit kernels in RHEL6 so the kernel should be built with SLUB, alternatively increasing /sys/kernel/mm/hugepages-*/nr_hugepages and decreasing it in a loop may allow to reproduce it on 32bit x86) with CONFIG_SMP=n
2. grep nr_isolated /proc/zoneinfo
3.
Actual results: eventually the DMA zone nr_isolated_file should get fixed to 1 the NORMAL zone will go to -1 (4294967295). The VM may hang too because the -1 value of the normal zone will hang it in too_many_isolated().
Expected results: No hang and nr_isolated_* always >= 0 in a idle system (not -1).
Additional info:
During hang:
egrep 'Node|nr_isolated' /proc/zoneinfo
Node 0, zone DMA
nr_isolated_anon 0
nr_isolated_file 1
Node 0, zone Normal
nr_isolated_anon 0
nr_isolated_file 4294967295
Node 0, zone HighMem
nr_isolated_anon 0
nr_isolated_file 0
Comment 2RHEL Program Management
2011-06-13 09:29:50 UTC
This request was evaluated by Red Hat Product Management for inclusion
in a Red Hat Enterprise Linux maintenance release. Product Management has
requested further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed
products. This request is not yet committed for inclusion in an Update release.
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.
http://rhn.redhat.com/errata/RHSA-2011-1530.html
Description of problem: nr_isolated_file of zone DMA becomes fixed 1 and nr_isolated_file or zone NORMAL becomes fixed -1 How reproducible: not reproducible with CONFIG_SMP=y, and so far only reproduced on x86 32bit (maybe because of lack of ZONE_DMA32 with <4GB of ram and HIGHMEM4G=y [64G=n]). Steps to Reproduce: 1. run a lot of SLUB order 3 allocations or THP allocations invoking compaction (better on 32bit but THP isn't available on 32bit kernels in RHEL6 so the kernel should be built with SLUB, alternatively increasing /sys/kernel/mm/hugepages-*/nr_hugepages and decreasing it in a loop may allow to reproduce it on 32bit x86) with CONFIG_SMP=n 2. grep nr_isolated /proc/zoneinfo 3. Actual results: eventually the DMA zone nr_isolated_file should get fixed to 1 the NORMAL zone will go to -1 (4294967295). The VM may hang too because the -1 value of the normal zone will hang it in too_many_isolated(). Expected results: No hang and nr_isolated_* always >= 0 in a idle system (not -1). Additional info: During hang: egrep 'Node|nr_isolated' /proc/zoneinfo Node 0, zone DMA nr_isolated_anon 0 nr_isolated_file 1 Node 0, zone Normal nr_isolated_anon 0 nr_isolated_file 4294967295 Node 0, zone HighMem nr_isolated_anon 0 nr_isolated_file 0