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David Hildenbrand
5f47adf762
For now, distributions implement advanced udev rules to essentially - Don't online any hotplugged memory (s390x) - Online all memory to ZONE_NORMAL (e.g., most virt environments like hyperv) - Online all memory to ZONE_MOVABLE in case the zone imbalance is taken care of (e.g., bare metal, special virt environments) In summary: All memory is usually onlined the same way, however, the kernel always has to ask user space to come up with the same answer. E.g., Hyper-V always waits for a memory block to get onlined before continuing, otherwise it might end up adding memory faster than onlining it, which can result in strange OOM situations. This waiting slows down adding of a bigger amount of memory. Let's allow to specify a default online_type, not just "online" and "offline". This allows distributions to configure the default online_type when booting up and be done with it. We can now specify "offline", "online", "online_movable" and "online_kernel" via - "memhp_default_state=" on the kernel cmdline - /sys/devices/system/memory/auto_online_blocks just like we are able to specify for a single memory block via /sys/devices/system/memory/memoryX/state Signed-off-by: David Hildenbrand <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Reviewed-by: Wei Yang <[email protected]> Reviewed-by: Baoquan He <[email protected]> Acked-by: Michal Hocko <[email protected]> Acked-by: Pankaj Gupta <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> Cc: Oscar Salvador <[email protected]> Cc: "Rafael J. Wysocki" <[email protected]> Cc: Wei Yang <[email protected]> Cc: Benjamin Herrenschmidt <[email protected]> Cc: Eduardo Habkost <[email protected]> Cc: Haiyang Zhang <[email protected]> Cc: Igor Mammedov <[email protected]> Cc: "K. Y. Srinivasan" <[email protected]> Cc: Michael Ellerman <[email protected]> Cc: Paul Mackerras <[email protected]> Cc: Stephen Hemminger <[email protected]> Cc: Vitaly Kuznetsov <[email protected]> Cc: Wei Liu <[email protected]> Cc: Yumei Huang <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Linus Torvalds <[email protected]>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.