Re: Default zone_reclaim_mode = 1 on NUMA kernel is bad forfile/email/web servers

[Rob Mueller]

> This could be a screwy hardware issue as pointed out before. Certain
> controllers restrict the memory that I/O can be done to also (32 bit
> controller only able to do I/O to lower 2G?, controller on a PCI bus that
> is local only to a particular node) which would make balancing
> the file cache difficult.

Ah interesting. Is there an easy way to tell if this is an issue? It's an 
ARECA RAID controller, this is the lspci -vvv data from it...

03:00.0 RAID bus controller: Areca Technology Corp. Device 1680
       Subsystem: Areca Technology Corp. Device 1680
       Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr+ 
Stepping- SERR- FastB2B- DisINTx-
       Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- 
<TAbort- <MAbort- >SERR- <PERR- INTx-
       Latency: 0, Cache Line Size: 64 bytes
       Interrupt: pin A routed to IRQ 26
       Region 0: Memory at b1900000 (32-bit, non-prefetchable) [size=8K]
       Expansion ROM at b1c00000 [disabled] [size=64K]
       Capabilities: [98] Power Management version 2
               Flags: PMEClk- DSI- D1+ D2- AuxCurrent=0mA 
PME(D0-,D1-,D2-,D3hot-,D3cold-)
               Status: D0 PME-Enable- DSel=0 DScale=0 PME-
       Capabilities: [a0] Message Signalled Interrupts: Mask- 64bit+ 
Queue=0/1 Enable-
               Address: 0000000000000000  Data: 0000
       Capabilities: [d0] Express (v1) Endpoint, MSI 00
               DevCap: MaxPayload 512 bytes, PhantFunc 0, Latency L0s 
unlimited, L1 <1us
                       ExtTag- AttnBtn- AttnInd- PwrInd- RBE+ FLReset-
               DevCtl: Report errors: Correctable+ Non-Fatal+ Fatal+ 
Unsupported+
                       RlxdOrd+ ExtTag- PhantFunc- AuxPwr- NoSnoop+
                       MaxPayload 256 bytes, MaxReadReq 256 bytes
               DevSta: CorrErr+ UncorrErr- FatalErr- UnsuppReq+ AuxPwr- 
TransPend-
               LnkCap: Port #0, Speed 2.5GT/s, Width x8, ASPM unknown, 
Latency L0 <128ns, L1 unlimited
                       ClockPM- Suprise- LLActRep- BwNot-
               LnkCtl: ASPM Disabled; RCB 64 bytes Disabled- Retrain- 
CommClk+
                       ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
               LnkSta: Speed 2.5GT/s, Width x8, TrErr- Train- SlotClk+ 
DLActive- BWMgmt- ABWMgmt-
       Capabilities: [100] Advanced Error Reporting <?>
       Kernel driver in use: arcmsr



Rob

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