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Barry Song 9d57090e73 mm: fix swap_read_folio_zeromap() for large folios with partial zeromap
Patch series "mm: enable large folios swap-in support", v9.

Currently, we support mTHP swapout but not swapin.  This means that once
mTHP is swapped out, it will come back as small folios when swapped in. 
This is particularly detrimental for devices like Android, where more than
half of the memory is in swap.

The lack of mTHP swapin functionality makes mTHP a showstopper in
scenarios that heavily rely on swap.  This patchset introduces mTHP
swap-in support.  It starts with synchronous devices similar to zRAM,
aiming to benefit as many users as possible with minimal changes.


This patch (of 3):

There could be a corner case where the first entry is non-zeromap, but a
subsequent entry is zeromap.  In this case, we should not let
swap_read_folio_zeromap() return false since we will still read corrupted
data.

Additionally, the iteration of test_bit() is unnecessary and can be
replaced with bitmap operations, which are more efficient.

We can adopt the style of swap_pte_batch() and folio_pte_batch() to
introduce swap_zeromap_batch() which seems to provide the greatest
flexibility for the caller.  This approach allows the caller to either
check if the zeromap status of all entries is consistent or determine the
number of contiguous entries with the same status.

Since swap_read_folio() can't handle reading a large folio that's
partially zeromap and partially non-zeromap, we've moved the code to
mm/swap.h so that others, like those working on swap-in, can access it.

Link: https://lkml.kernel.org/r/20240908232119.2157-1-21cnbao@gmail.com
Link: https://lkml.kernel.org/r/20240908232119.2157-2-21cnbao@gmail.com
Fixes: 0ca0c24e32 ("mm: store zero pages to be swapped out in a bitmap")
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: Usama Arif <usamaarif642@gmail.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Chuanhua Han <hanchuanhua@oppo.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Gao Xiang <xiang@kernel.org>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kairui Song <ryncsn@gmail.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Kanchana P Sridhar <kanchana.p.sridhar@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-17 01:07:01 -07:00
arch mm: z3fold: deprecate CONFIG_Z3FOLD 2024-09-17 01:07:00 -07:00
block block: fix detection of unsupported WRITE SAME in blkdev_issue_write_zeroes 2024-08-28 08:49:25 -06:00
certs kbuild: use $(src) instead of $(srctree)/$(src) for source directory 2024-05-10 04:34:52 +09:00
crypto crypto: testmgr - generate power-of-2 lengths more often 2024-07-13 11:50:28 +12:00
Documentation zram: support priority parameter in recompression 2024-09-09 16:39:12 -07:00
drivers vfio/pci: implement huge_fault support 2024-09-17 01:07:00 -07:00
fs mm,tmpfs: consider end of file write in shmem_is_huge 2024-09-09 16:39:12 -07:00
include set_memory: add __must_check to generic stubs 2024-09-17 01:07:00 -07:00
init mm: fix typo in Kconfig 2024-09-01 20:25:45 -07:00
io_uring io_uring/kbuf: return correct iovec count from classic buffer peek 2024-08-30 10:45:54 -06:00
ipc ipc/shm, mm: drop do_vma_munmap() 2024-09-03 21:15:52 -07:00
kernel resource, kunit: add test case for region_intersects() 2024-09-17 01:07:00 -07:00
lib resource, kunit: add test case for region_intersects() 2024-09-17 01:07:00 -07:00
LICENSES
mm mm: fix swap_read_folio_zeromap() for large folios with partial zeromap 2024-09-17 01:07:01 -07:00
net Including fixes from bluetooth, wireless and netfilter. 2024-08-30 06:14:39 +12:00
rust Rust fixes for v6.11 2024-08-16 11:24:06 -07:00
samples kmemleak-test: add percpu leak 2024-09-01 20:25:50 -07:00
scripts kasan: simplify and clarify Makefile 2024-09-03 21:15:35 -07:00
security Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging 2024-09-01 09:18:48 +12:00
sound sound fixes for 6.11-rc6 2024-08-28 06:24:22 +12:00
tools selftests/mm: relax test to fail after 100 migration failures 2024-09-09 16:39:05 -07:00
usr initramfs: shorten cmd_initfs in usr/Makefile 2024-07-16 01:07:52 +09:00
virt KVM: use follow_pfnmap API 2024-09-17 01:06:59 -07:00
.clang-format Docs: Move clang-format from process/ to dev-tools/ 2024-06-26 16:36:00 -06:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: add script and target to generate pacman package 2024-07-22 01:24:22 +09:00
.mailmap ARM: SoC fixes for 6.11, part 2 2024-09-01 06:42:13 +12:00
.rustfmt.toml
COPYING
CREDITS tracing: Update of MAINTAINERS and CREDITS file 2024-07-18 14:08:42 -07:00
Kbuild
Kconfig
MAINTAINERS tools: add skeleton code for userland testing of VMA logic 2024-09-01 20:25:55 -07:00
Makefile Linux 6.11-rc6 2024-09-01 19:46:02 +12:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

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 reStructuredText 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.