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Chengming Zhou d58a361b03 mm/ksm: don't waste time searching stable tree for fast changing page
The code flow in cmp_and_merge_page() is suboptimal for handling the ksm
page and non-ksm page at the same time.  For example:

- ksm page
 1. Mostly just return if this ksm page is not migrated and this rmap_item
    has been on the rmap hlist. Or we have to fix this rmap_item mapping.
 2. But we absolutely don't need to checksum for this ksm page, since it
    can't change.

- non-ksm page
 1. First don't need to waste time searching stable tree if fast changing.
 2. Should try to merge with zero page before search the stable tree.
 3. Then search stable tree to find mergeable ksm page.

This patch optimizes the code flow so the handling differences between ksm
page and non-ksm page become clearer and more efficient too.

Link: https://lkml.kernel.org/r/20240621-b4-ksm-scan-optimize-v2-2-1c328aa9e30b@linux.dev
Signed-off-by: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Stefan Roesch <shr@devkernel.io>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-04 18:05:50 -07:00
arch kmsan: enable on s390 2024-07-03 19:30:26 -07:00
block block: unmap and free user mapped integrity via submitter 2024-06-12 11:00:50 -06:00
certs kbuild: use $(src) instead of $(srctree)/$(src) for source directory 2024-05-10 04:34:52 +09:00
crypto This push fixes a bug in the new ecc P521 code as well as a buggy 2024-05-20 08:47:54 -07:00
Documentation kmsan: allow disabling KMSAN checks for the current task 2024-07-03 19:30:22 -07:00
drivers s390/irqflags: do not instrument arch_local_irq_*() with KMSAN 2024-07-03 19:30:25 -07:00
fs readahead: drop index argument of page_cache_async_readahead() 2024-07-03 19:30:27 -07:00
include readahead: drop index argument of page_cache_async_readahead() 2024-07-03 19:30:27 -07:00
init gcc: disable '-Warray-bounds' for gcc-9 2024-06-15 10:43:04 -07:00
io_uring io_uring: signal SQPOLL task_work with TWA_SIGNAL_NO_IPI 2024-06-24 19:46:15 -06:00
ipc Mainly singleton patches, documented in their respective changelogs. 2024-05-19 14:02:03 -07:00
kernel ftrace: unpoison ftrace_regs in ftrace_ops_list_func() 2024-07-03 19:30:21 -07:00
lib lib/zlib: unpoison DFLTCC output buffers 2024-07-03 19:30:23 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm/ksm: don't waste time searching stable tree for fast changing page 2024-07-04 18:05:50 -07:00
net NFS client bugfixes for Linux 6.10 2024-06-29 13:48:24 -07:00
rust rust: avoid unused import warning in rusttest 2024-06-11 23:33:28 +02:00
samples kmemleak-test: add missing MODULE_DESCRIPTION() macro 2024-07-03 19:30:04 -07:00
scripts kbuild: scripts/gdb: bring the "abspath" back 2024-06-27 04:20:32 +09:00
security lsm/stable-6.10 PR 20240617 2024-06-17 18:35:12 -07:00
sound ASoC: Fixes for v6.10 2024-06-26 22:02:55 +02:00
tools selftests/damon/damon_nr_regions: test online-tuned max_nr_regions 2024-07-03 19:30:29 -07:00
usr kbuild: use $(src) instead of $(srctree)/$(src) for source directory 2024-05-10 04:34:52 +09:00
virt KVM fixes for 6.10 2024-06-21 08:03:55 -04:00
.clang-format clang-format: Update with v6.7-rc4's for_each macro list 2023-12-08 23:54:38 +01:00
.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: create a list of all built DTB files 2024-02-19 18:20:39 +09:00
.mailmap bpf-for-netdev 2024-06-14 17:57:10 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Drop Gustavo Pimentel as PCI DWC Maintainer 2024-03-27 13:41:02 -05:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS IOMMU Fixes for Linux v6.10-rc5 2024-06-28 09:18:01 -07:00
Makefile Linux 6.10-rc6 2024-06-30 14:40:44 -07:00
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.