cb3ea7684a
commit55d134a7b4upstream. The hugetlb_cma code passes 0 in the order_per_bit argument to cma_declare_contiguous_nid (the alignment, computed using the page order, is correctly passed in). This causes a bit in the cma allocation bitmap to always represent a 4k page, making the bitmaps potentially very large, and slower. It would create bitmaps that would be pretty big. E.g. for a 4k page size on x86, hugetlb_cma=64G would mean a bitmap size of (64G / 4k) / 8 == 2M. With HUGETLB_PAGE_ORDER as order_per_bit, as intended, this would be (64G / 2M) / 8 == 4k. So, that's quite a difference. Also, this restricted the hugetlb_cma area to ((PAGE_SIZE << MAX_PAGE_ORDER) * 8) * PAGE_SIZE (e.g. 128G on x86) , since bitmap_alloc uses normal page allocation, and is thus restricted by MAX_PAGE_ORDER. Specifying anything about that would fail the CMA initialization. So, correctly pass in the order instead. Link: https://lkml.kernel.org/r/20240404162515.527802-2-fvdl@google.com Fixes:cf11e85fc0("mm: hugetlb: optionally allocate gigantic hugepages using cma") Signed-off-by: Frank van der Linden <fvdl@google.com> Acked-by: Roman Gushchin <roman.gushchin@linux.dev> Acked-by: David Hildenbrand <david@redhat.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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.