On 07/19/2017 09:23 AM, Johnny Hughes wrote: > On 07/19/2017 04:27 AM, Piotr Gackiewicz wrote: >> On Mon, 17 Jul 2017, Johnny Hughes wrote: >> >>> Are the testing kernels (kernel-4.9.37-29.el7 and kernel-4.9.37-29.el6, >>> with the one config file change) working for everyone: >>> >>> (turn off: CONFIG_IO_STRICT_DEVMEM) >> >> Hello. >> Maybe it's not the most appropriate thread or time, but I have been >> signalling it before: >> >> 4.9.* kernels do not work well for me any more (and for other people >> neither, as I know). Last stable kernel was 4.9.13-22. >> >> Since 4.9.25-26 I do often get: >> on 3 supermicro servers (different generations): >> - memory allocation errors on Dom0 and corresponding lost lost page writes >> due to buffer I/O error on PV guests >> - after such memory allocation error od dom0 I have spotted also: >> - NFS client hangups on guests (server not responding, still trying >> => server OK) >> - iptables lockups on PV guest reboot >> >> on 1 supermicro server: >> - memory allocation errors on Dom0 and SATA lockups (many, if not SATA >> channels at >> - once): >> exception Emask 0x0 SAct 0x20 SErr 0x0 action 0x6 frozen >> hard resetting link >> failed to IDENTIFY (I/O error, err_mask=0x4) >> then: blk_update_request: I/O error, dev sd., sector .... >> >> >> All of these machines have been tested with memtest, no detected memory >> problems. >> No such things occur, when I boot 4.9.13-22 >> Most of my guests are centos 6 x86_64, bridged. >> >> Do anyone had such problems, dealt with it somehow? >> >> >> Since spotting these errors I have done many tests, compiled and tested to >> point out single code change (kernel version, patch) - no conclusions yet. >> >> But one has changed much between 4.9.13 and 4.9.25: kernel size and >> configuration. >> 4.9.13 size was 6MB and 4.9.24 is 7.1MB. Many modules have been >> compiled into kernel, here is shortened, but significant list: >> - iptables (NETFILTER_XTABLES, IP_NF_FILTER, IP_NF_TARGET_REJECT) >> - SATA_AHCI >> - ATA_AHCI (PATA, what a heck?) >> - FBDEV_FRONTEND >> - HID_MAGICKMOUSE >> - HID_NTRIG >> - USB_XHCI >> - INTEL_SMARTCONNECT >> > Modules that are not loaded are not used. It has no impact at all on > performance or compatibility unless it is used. If you take an lsmod of > the kernel that works and one of the kernel with issues, we can see if > there are LOADED modules that might cause issues. > > The modules that are built are the same as Fedora and if in the RHEL 7 > kernel, RHEL 7. > > We did troubleshoot and turn off some things recently, one thing in > particular was CONFIG_IO_STRICT_DEVMEM , which is on in fedora, but > which is off in some other distros and causes issues with ISCSI and some > other things. > > We also added some specific xen patches, one for netback queue, one for > apic, one for nested dom0. Also upstream has added in several xen > patches since 4.9.13. There are several very important patches in this kernel for xen (for example): https://cdn.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.9.36 -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 198 bytes Desc: OpenPGP digital signature URL: <http://lists.centos.org/pipermail/centos-virt/attachments/20170719/6f100d53/attachment-0005.sig>