050dcb5c85
Patch series "huge tmpfs: shmem_is_huge() fixes and cleanups". A series of huge tmpfs fixes and cleanups. This patch (of 9): shmem_fallocate() goes to a lot of trouble to leave its newly allocated pages !Uptodate, partly to identify and undo them on failure, partly to leave the overhead of clearing them until later. But the huge page case did not skip to the end of the extent, walked through the tail pages one by one, and appeared to work just fine: but in doing so, cleared and Uptodated the huge page, so there was no way to undo it on failure. And by setting Uptodate too soon, it messed up both its nr_falloced and nr_unswapped counts, so that the intended "time to give up" heuristic did not work at all. Now advance immediately to the end of the huge extent, with a comment on why this is more than just an optimization. But although this speeds up huge tmpfs fallocation, it does leave the clearing until first use, and some users may have come to appreciate slow fallocate but fast first use: if they complain, then we can consider adding a pass to clear at the end. Link: https://lkml.kernel.org/r/da632211-8e3e-6b1-aee-ab24734429a0@google.com Link: https://lkml.kernel.org/r/16201bd2-70e-37e2-e89b-5f929430da@google.com Fixes: 800d8c63b2e9 ("shmem: add huge pages support") Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: Yang Shi <shy828301@gmail.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Rik van Riel <riel@surriel.com> Cc: Matthew Wilcox <willy@infradead.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.