https://bugzilla.kernel.org/show_bug.cgi?id=213837
Erhard F. (erhar...@mailbox.org) changed:
What|Removed |Added
Attachment #298393|0 |1
is obsolete|
https://bugzilla.kernel.org/show_bug.cgi?id=213837
Erhard F. (erhar...@mailbox.org) changed:
What|Removed |Added
Attachment #298019|0 |1
is obsolete|
The current partition migration implementation does not freeze the
user space and the user space can continue open VAS windows. So
when migration_in_progress flag is enabled, VAS open window
API returns -EBUSY.
Signed-off-by: Haren Myneni
---
arch/powerpc/platforms/pseries/vas.c | 13
Since the VAS windows belong to the VAS hardware resource, the
hypervisor expects the partition to close them on source partition
and reopen them after the partition migrated on the destination
machine.
This handler is called before pseries_suspend() to close these
windows and again invoked
VAS is a hardware engine stays on the chip. So when the partition
migrates, all VAS windows on the source system have to be closed
and reopen them on the destination after migration.
This patch make changes to the current reconfig_open/close_windows
functions to support migration:
- Set
The coprocessor capabilities struct is used to get default and
QoS capabilities from the hypervisor during init, DLPAR event and
migration. So instead of allocating this struct for each event,
define global struct and reuse it which allows the migration code
to avoid adding an error path.
Also
Virtual Accelerator Switchboard (VAS) is an engine stays on the
chip. So all windows opened on a specific engine belongs to VAS
the chip. The hypervisor expects the partition to close all
active windows on the sources system and reopen them after
migration on the destination machine.
This patch
pseries supports two types of credits - Default (uses normal priority
FIFO) and Qality of service (QoS uses high priority FIFO). The user
decides the number of QoS credits and sets this value with HMC
interface. With the core add/removal, this value can be changed in HMC
which invokes drmgr to
The hypervisor provides the available VAS GZIP capabilities such
as default or QoS window type and the target available credits in
each type. This patch creates sysfs entries and exports the target,
used and the available credits for each feature.
This interface can be used by the user space to
VAS windows can be closed in the hypervisor due to lost credits
when the core is removed and the kernel gets fault for NX
requests on these in-active windows. If these credits are
available later for core add, reopen these windows and set them
active. When the OS sees page faults on these active
The hypervisor assigns vas credits (windows) for each LPAR based
on the number of cores configured in that system. The OS is
expected to release credits when cores are removed, and may
allocate more when cores are added. So there is a possibility of
using excessive credits (windows) in the LPAR
The paste address mapping is done with mmap() after the window is
opened with ioctl. If the window is closed by OS in the hypervisor
due to DLPAR after this mmap(), the paste instruction returns
failure until the OS reopens this window again. But before mmap(),
DLPAR core removal can happen
The VAS window may not be active if the system looses credits and
the NX generates page fault when it receives request on unmap
paste address.
The kernel handles the fault by remap new paste address if the
window is active again, Otherwise return the paste instruction
failure if the executed
The user space opens VAS windows and issues NX requests by pasting
CRB on the corresponding paste address mmap. When the system lost
credits due to core removal, the kernel has to close the window in
the hypervisor and make the window inactive by unmapping this paste
address. Also the OS has to
The kernel sets the VAS window with PID when it is opened in
the hypervisor. During DLPAR operation, windows can be closed and
reopened in the hypervisor when the credit is available. So saves
this PID in pseries_vas_window struct when the window is opened
initially and reuse it later during
nr_total/nr_used_credits provides credits usage to user space
via sysfs and the same interface can be used on PowerNV in
future. Changed with proper naming so that applicable on both
pseries and PowerNV.
Signed-off-by: Haren Myneni
Reviewed-by: Nicholas Piggin
---
PowerPC provides HW compression with NX coprocessor. This feature
is available on both PowerNV and PowerVM and included in Linux.
Since each powerpc chip has one NX coprocessor, the VAS introduces
the concept of windows / credits to manage access to this hardware
resource. On powerVM, these
Hello:
This patch was applied to netdev/net.git (master)
by David S. Miller :
On Thu, 17 Feb 2022 14:35:49 +0100 you wrote:
> All functions defined as static inline in net/checksum.h are
> meant to be inlined for performance reason.
>
> But since commit ac7c3e4ff401 ("compiler: enable
>
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