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Hugh Dickins 050dcb5c85 huge tmpfs: fix fallocate(vanilla) advance over huge pages
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: 800d8c63b2 ("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>
2021-09-03 09:58:11 -07:00
arch mm/gup: remove try_get_page(), call try_get_compound_head() directly 2021-09-03 09:58:11 -07:00
block block-5.14-2021-08-27 2021-08-27 16:08:29 -07:00
certs
crypto crypto: drbg - select SHA512 2021-07-16 15:49:31 +08:00
Documentation RISC-V Fixes for 5.14-rc7 2021-08-21 11:04:26 -07:00
drivers One hot fix for a NULL pointer deref in the Renesas usb clk driver 2021-08-29 12:52:17 -07:00
fs fs, mm: fix race in unlinking swapfile 2021-09-03 09:58:11 -07:00
include shmem: use raw_spinlock_t for ->stat_lock 2021-09-03 09:58:11 -07:00
init init: Suppress wrong warning for bootconfig cmdline parameter 2021-08-12 13:35:57 -04:00
ipc Merge branch 'akpm' (patches from Andrew) 2021-07-02 12:08:10 -07:00
kernel - Have get_push_task() check whether current has migration disabled and 2021-08-29 10:54:14 -07:00
lib lib: use PFN_PHYS() in devmem_is_allowed() 2021-08-13 14:09:32 -10:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm huge tmpfs: fix fallocate(vanilla) advance over huge pages 2021-09-03 09:58:11 -07:00
net This is a one-liner fix for a serious bug that can cause the server to 2021-08-26 13:26:40 -07:00
samples Networking fixes for 5.14-rc2, including fixes from bpf and netfilter. 2021-07-14 09:24:32 -07:00
scripts Kbuild fixes for v5.14 (2nd) 2021-08-07 10:03:02 -07:00
security bpf: Add lockdown check for probe_write_user helper 2021-08-10 10:10:10 +02:00
sound another sound-fixes for 5.14-rc7 2021-08-20 12:31:10 -07:00
tools Networking fixes for 5.14-rc7, including fixes from bpf, wireless and 2021-08-19 12:33:43 -07:00
usr
virt KVM: Do not leak memory for duplicate debugfs directories 2021-08-04 06:02:03 -04:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap m68k updates for v5.14 2021-06-28 14:01:03 -07:00
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS MAINTAINERS: exfat: update my email address 2021-08-25 12:25:12 -07:00
Makefile Linux 5.14 2021-08-29 15:04:50 -07:00
README

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.