9cd20f3fe0
Highatomic reserves are set to roughly 1% of zone for maximum and a pageblock size for minimum. Encountered a system with the below configuration: Normal free:7728kB boost:0kB min:804kB low:1004kB high:1204kB reserved_highatomic:8192KB managed:49224kB On such systems, even a single pageblock makes highatomic reserves are set to ~8% of the zone memory. This high value can easily exert pressure on the zone. Per discussion with Michal and Mel, it is not much useful to reserve the memory for highatomic allocations on such small systems[1]. Since the minimum size for high atomic reserves is always going to be a pageblock size and if 1% of zone managed pages is going to be below pageblock size, don't reserve memory for high atomic allocations. Thanks Michal for this suggestion[2]. Since no memory is being reserved for high atomic allocations and if respective allocation failures are seen, this patch can be reverted. [1] https://lore.kernel.org/linux-mm/20231117161956.d3yjdxhhm4rhl7h2@techsingularity.net/ [2] https://lore.kernel.org/linux-mm/ZVYRJMUitykepLRy@tiehlicka/ Link: https://lkml.kernel.org/r/c3a2a48e2cfe08176a80eaf01c110deb9e918055.1700821416.git.quic_charante@quicinc.com Signed-off-by: Charan Teja Kalla <quic_charante@quicinc.com> Acked-by: David Rientjes <rientjes@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@suse.com> Cc: Pavankumar Kondeti <quic_pkondeti@quicinc.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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.