b5bade978e
Patch series "Improve the migration stats". According to talk with Zi Yan [1], this patch set changes the return value of migrate_pages() to avoid returning a number which is larger than the number of pages the users tried to migrate by move_pages() syscall. Also fix the hugetlb migration stats and migration stats in trace_mm_compaction_migratepages(). [1] https://lore.kernel.org/linux-mm/7E44019D-2A5D-4BA7-B4D5-00D4712F1687@nvidia.com/ This patch (of 3): As Zi Yan pointed out, the syscall move_pages() can return a non-migrated number larger than the number of pages the users tried to migrate, when a THP page is failed to migrate. This is confusing for users. Since other migration scenarios do not care about the actual non-migrated number of pages except the memory compaction migration which will fix in following patch. Thus we can change the return value to return the number of {normal page, THP, hugetlb} instead to avoid this issue, and the number of THP splits will be considered as the number of non-migrated THP, no matter how many subpages of the THP are migrated successfully. Meanwhile we should still keep the migration counters using the number of normal pages. Link: https://lkml.kernel.org/r/cover.1636275127.git.baolin.wang@linux.alibaba.com Link: https://lkml.kernel.org/r/6486fabc3e8c66ff613e150af25e89b3147977a6.1636275127.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Signed-off-by: Zi Yan <ziy@nvidia.com> Co-developed-by: Zi Yan <ziy@nvidia.com> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@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.