Did the limits for RAM on Home edition get changed with SFOS 16.05.2 MR2? I'm only seeing 4GB after update. Still only showing 4GB after rolling back to SFOS 16.05.1 MR-1. I was seeing 6GB usable before upgrade.
Hi All,
We have received all the output and our Dev Team is working on this. I will be more transparent by saying that we are trying to get remote access to some of the customers who are affected by this issue. Enabling access ID and allowing SSH access to our IP address can help us investigate. If anyone can share these access to us then please DM me the details. You will be informed prior to any changes or access.
Thanks
Thanks to the DEVS for taking the time to look at this.
To me it comes down to properly adjusting the mem= value to account for where a system maps memory. Many newer systems will map a large chunk of the memory starting at the 4GB address location. mem=6G will NOT allow for the allocation of any memory past the 6GB address pointer. It does NOT take bios memory mapping into account. Some users may have an options to change that mapping. My BIOS does not.
So far the information provided that i have looked at in these posts points to anyone with that BIOS memory remapping to 4GB addresses as being impacted. I've looked at some of my VM's and the memory maps are much simpler on those which probably explains why some people with VM's were not impacted.
One solution i can think of is adjusting up the value of mem= upwards(example below) based on e820 memory maps and/or /proc/iomem until the desired result is achieved. The problem with /proc/iomem is that anyone already booted on mem=6G will not have the full map readily available. The other solution i can think of is a daemon or driver that simply allocates+pins real memory until the system is down to 6GB free and removing mem= from the kernel options.
Here's the current memory map from my system reported with a variation of the script i posted a while back that looks at "System RAM" in /proc/iomem
00001000-0009c7ff | Region: START 0 MB END 0 MB | SIZE: 0 MB 621 KB 00100000-1effffff | Region: START 1 MB END 495 MB | SIZE: 494 MB 506879 KB 20200000-7b217fff | Region: START 514 MB END 1970 MB | SIZE: 1456 MB 1491039 KB 7b293000-7b3bafff | Region: START 1970 MB END 1971 MB | SIZE: 1 MB 1183 KB 7bb30000-7bffffff | Region: START 1979 MB END 1983 MB | SIZE: 4 MB 4927 KB 100000000-17fffffff | Region: START 4096 MB END 6143 MB | SIZE: 2047 MB 2097151 KB
Total Bytes : 4200249338Total KBytes: 4101805Total MBytes: 4005
Here's a memory map report from what davidwilliams1 provided.
00001000-00089bff | Region: START 0 MB END 0 MB | SIZE: 0 MB 546 KB
00100000-1effffff | Region: START 1 MB END 495 MB | SIZE: 494 MB 506879 KB
1f100000-1fffffff | Region: START 497 MB END 511 MB | SIZE: 14 MB 15359 KB
20100000-78825fff | Region: START 513 MB END 1928 MB | SIZE: 1415 MB 1449111 KB
78b81000-78b81fff | Region: START 1931 MB END 1931 MB | SIZE: 0 MB 3 KB
78bc4000-78d2ffff | Region: START 1931 MB END 1933 MB | SIZE: 1 MB 1455 KB
78ffa000-78ffffff | Region: START 1935 MB END 1935 MB | SIZE: 0 MB 23 KB
100000000-17fffffff | Region: START 4096 MB END 6143 MB | SIZE: 2047 MB 2097151 KBTotal Bytes : 4168227832Total KBytes: 4070534Total MBytes: 3975
Here's a theoretical/handmade example map that shows what a modified mem=8283M value for my host would do. That value should provide me with exactly 6GB of usable ram.
00001000-0009c7ff | Region: START 0 MB END 0 MB | SIZE: 0 MB 621 KB 00100000-1effffff | Region: START 1 MB END 495 MB | SIZE: 494 MB 506879 KB 20200000-7b217fff | Region: START 514 MB END 1970 MB | SIZE: 1456 MB 1491039 KB 7b293000-7b3bafff | Region: START 1970 MB END 1971 MB | SIZE: 1 MB 1183 KB 7bb30000-7bffffff | Region: START 1979 MB END 1983 MB | SIZE: 4 MB 4927 KB 100000000-205B00000 | Region: START 4096 MB END 8283 MB | SIZE: 4187 MB 4287488 KB
Total Bytes : 6443153403Total KBytes: 6292141Total MBytes: 6144
My original bios(e820) usable memory map before mem=6G from syslog.log is below.
[mem 0x0000000000000000-0x000000000009c7ff] usable [mem 0x0000000000100000-0x000000001effffff] usable [mem 0x0000000020200000-0x000000007b217fff] usable [mem 0x000000007b293000-0x000000007b3bafff] usable [mem 0x000000007bb30000-0x000000007bffffff] usable [mem 0x0000000100000000-0x000000027fffffff] usable
The impact of mem=6G from the log is also below. It removes any memory over the 6GB address mark. Depending on memory usage below 4G and how things are mapped on different boards different users will see different amounts of free memory. I think the 2 examples above should show that.
remove [mem 0x180000000-0xfffffffffffffffe] usable
I know i have made a lot of posts on this but i have been troubleshooting UNIX(SunOS/Solaris/AIX/HP-UX/Linux/NetBSD) issues since 1996 and have used Linux since the 0.98 days and am just interested in seeing the problem resolved as soon as possible. If there's any questions DM or email me. I think most of the info needed to fix this is in these posts. It boils down to mem= being an overly simplistic implementation, and there being no good alternative to limit usable memory to a specific value.
I would personally fix this by creating a program/script to calculate a proper mem= value based on the system memory map, or using some other means to make extra memory unusable.
Thanks. Hope you guys figure this out Before the next MR :)
Agree about this.
I think that is a better solution to handle "overcapacity" by just allocating it, as this would then allow the system to also manage the "overcapacity" as "hot spare".
So when it detects a memory failure, it could remap away that failure by using the capacity that is over license.
Example: You have 8 GB. Your license is 6 GB. If a 1 GB chip fails on one of the ram sticks, it could remap it so it uses lets say the first 5 GB, then makes the failed 1 GB unavailabe and then uses 1 GB of the "overcapacity", and then makes the last 1 GB unavailable, so 6 GB stays usable at all times, even at hardware failure.
Agree about this.
I think that is a better solution to handle "overcapacity" by just allocating it, as this would then allow the system to also manage the "overcapacity" as "hot spare".
So when it detects a memory failure, it could remap away that failure by using the capacity that is over license.
Example: You have 8 GB. Your license is 6 GB. If a 1 GB chip fails on one of the ram sticks, it could remap it so it uses lets say the first 5 GB, then makes the failed 1 GB unavailabe and then uses 1 GB of the "overcapacity", and then makes the last 1 GB unavailable, so 6 GB stays usable at all times, even at hardware failure.
