similar to: [PATCH v1 0/5] mm/memory_hotplug: selective merging of system ram resources

Some add_memory*() users add memory in small, contiguous memory blocks. Examples include virtio-mem, hyper-v balloon, and the XEN balloon. This can quickly result in a lot of memory resources, whereby the actual resource boundaries are not of interest (e.g., it might be relevant for DIMMs, exposed via /proc/iomem to user space). We really want to merge added resources in this scenario where

Some add_memory*() users add memory in small, contiguous memory blocks. Examples include virtio-mem, hyper-v balloon, and the XEN balloon. This can quickly result in a lot of memory resources, whereby the actual resource boundaries are not of interest (e.g., it might be relevant for DIMMs, exposed via /proc/iomem to user space). We really want to merge added resources in this scenario where

Some add_memory*() users add memory in small, contiguous memory blocks. Examples include virtio-mem, hyper-v balloon, and the XEN balloon. This can quickly result in a lot of memory resources, whereby the actual resource boundaries are not of interest (e.g., it might be relevant for DIMMs, exposed via /proc/iomem to user space). We really want to merge added resources in this scenario where

Some add_memory*() users add memory in small, contiguous memory blocks. Examples include virtio-mem, hyper-v balloon, and the XEN balloon. This can quickly result in a lot of memory resources, whereby the actual resource boundaries are not of interest (e.g., it might be relevant for DIMMs, exposed via /proc/iomem to user space). We really want to merge added resources in this scenario where

Some add_memory*() users add memory in small, contiguous memory blocks. Examples include virtio-mem, hyper-v balloon, and the XEN balloon. This can quickly result in a lot of memory resources, whereby the actual resource boundaries are not of interest (e.g., it might be relevant for DIMMs, exposed via /proc/iomem to user space). We really want to merge added resources in this scenario where

Some add_memory*() users add memory in small, contiguous memory blocks. Examples include virtio-mem, hyper-v balloon, and the XEN balloon. This can quickly result in a lot of memory resources, whereby the actual resource boundaries are not of interest (e.g., it might be relevant for DIMMs, exposed via /proc/iomem to user space). We really want to merge added resources in this scenario where

This series is based on [1]: [PATCH v2 00/10] virtio-mem: paravirtualized memory That will hopefull get picked up soon, rebased to -next. The following patches were reverted from -next [2]: [PATCH 0/3] kexec/memory_hotplug: Prevent removal and accidental use As discussed in that thread, they should be reverted from -next already. In theory, if people agree, we could take the first two patches

Clang warns: kernel/resource.c:1281:53: warning: operator '?:' has lower precedence than '|'; '|' will be evaluated first [-Wbitwise-conditional-parentheses] new_res = alloc_resource(GFP_KERNEL | alloc_nofail ? __GFP_NOFAIL : 0); ~~~~~~~~~~~~~~~~~~~~~~~~~ ^ kernel/resource.c:1281:53: note: place parentheses around the '|'

This is the follow up of [1]: [PATCH v1 0/3] mm/memory_hotplug: Make virtio-mem play nicely with kexec-tools I realized that this is not only helpful for virtio-mem, but also for dax/kmem - it's a fix for that use case (see patch #3) of persistent memory. Also, while testing, I discovered that kexec-tools will *not* add dax/kmem memory (anything not directly under the root when parsing

On 21.08.20 12:34, David Hildenbrand wrote: > Let's reuse the new mechanism to merge system ram resources below the > root. We are the only one hotplugging system ram (e.g., DIMMs don't apply), > so this is safe to be used. > > Cc: Andrew Morton <akpm at linux-foundation.org> > Cc: Michal Hocko <mhocko at suse.com> > Cc: Boris Ostrovsky <boris.ostrovsky

Let's make sure splitting a resource on memory hotunplug will never fail. This will become more relevant once we merge selected system ram resources - then, we'll trigger that case more frequently on memory hotunplug. In general, this function is already unlikely to fail. When we remove memory, we free up quite a lot of metadata (memmap, page tables, memory block device, etc.). The only

Let's make sure splitting a resource on memory hotunplug will never fail. This will become more relevant once we merge selected System RAM resources - then, we'll trigger that case more often on memory hotunplug. In general, this function is already unlikely to fail. When we remove memory, we free up quite a lot of metadata (memmap, page tables, memory block device, etc.). The only reason

@Andrew, @Mst, I suggest the whole series (including the virtio-mem change) goes via the -mm tree. Currently, virtio-mem does not really support ZONE_MOVABLE. While it allows to online fully plugged memory blocks to ZONE_MOVABLE, it does not allow to online partially-plugged memory blocks to ZONE_MOVABLE and will never consider such memory blocks when unplugging memory. This might be surprising

@Andrew can we give this a churn and consider it for v5.9 in case there are no more comments? Patch #1-#4 have RB's, patch #5 is virtio-mem stuff maintained by me, patch #6 is just a doc update. --- Currently, virtio-mem does not really support ZONE_MOVABLE. While it allows to online fully plugged memory blocks to ZONE_MOVABLE, it does not allow to online partially-plugged memory blocks to

@Andrew can we give this a churn and consider it for v5.9 in case there are no more comments? Patch #1-#4 have RB's, patch #5 is virtio-mem stuff maintained by me, patch #6 is just a doc update. --- Currently, virtio-mem does not really support ZONE_MOVABLE. While it allows to online fully plugged memory blocks to ZONE_MOVABLE, it does not allow to online partially-plugged memory blocks to

For 5.10. Patch #1-#4,#6 have RBs or ACKs, patch #5 is virtio-mem stuff maintained by me. This should go via the -mm tree. --- When introducing virtio-mem, the semantics of ZONE_MOVABLE were rather unclear, which is why we special-cased ZONE_MOVABLE such that partially plugged blocks would never end up in ZONE_MOVABLE. Now that the semantics are much clearer (and are documented in patch #6),

For 5.10. Patch #1-#4,#6 have RBs or ACKs, patch #5 is virtio-mem stuff maintained by me. This should go via the -mm tree. --- When introducing virtio-mem, the semantics of ZONE_MOVABLE were rather unclear, which is why we special-cased ZONE_MOVABLE such that partially plugged blocks would never end up in ZONE_MOVABLE. Now that the semantics are much clearer (and are documented in patch #6),

@Andrew can we give this a churn and consider it for v5.9 in case there are no more comments? Patch #1-#4,#6 have RBss or ACKs, patch #5 is virtio-mem stuff maintained by me (and MST is aware). --- When introducing virtio-mem, the semantics of ZONE_MOVABLE were rather unclear, which is why we special-cased ZONE_MOVABLE such that partially plugged blocks would never end up in ZONE_MOVABLE. Now

@Andrew can we give this a churn and consider it for v5.9 in case there are no more comments? Patch #1-#4,#6 have RBss or ACKs, patch #5 is virtio-mem stuff maintained by me (and MST is aware). --- When introducing virtio-mem, the semantics of ZONE_MOVABLE were rather unclear, which is why we special-cased ZONE_MOVABLE such that partially plugged blocks would never end up in ZONE_MOVABLE. Now

On Tue, Sep 08, 2020 at 10:10:07PM +0200, David Hildenbrand wrote: > IORESOURCE_MEM_DRIVER_MANAGED currently uses an unused PnP bit, which is > always set to 0 by hardware. This is far from beautiful (and confusing), > and the bit only applies to SYSRAM. So let's move it out of the > bus-specific (PnP) defined bits. > > We'll add another SYSRAM specific bit soon. If we