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Linux kernel source tree
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By using a few values in the top byte, users of page_type can store up to 24 bits of additional data in page_type. It also reduces the code size as (with replacement of READ_ONCE() with data_race()), the kernel can check just a single byte. eg: ffffffff811e3a79: 8b 47 30 mov 0x30(%rdi),%eax ffffffff811e3a7c: 55 push %rbp ffffffff811e3a7d: 48 89 e5 mov %rsp,%rbp ffffffff811e3a80: 25 00 00 00 82 and $0x82000000,%eax ffffffff811e3a85: 3d 00 00 00 80 cmp $0x80000000,%eax ffffffff811e3a8a: 74 4d je ffffffff811e3ad9 <folio_mapping+0x69> becomes: ffffffff811e3a69: 80 7f 33 f5 cmpb $0xf5,0x33(%rdi) ffffffff811e3a6d: 55 push %rbp ffffffff811e3a6e: 48 89 e5 mov %rsp,%rbp ffffffff811e3a71: 74 4d je ffffffff811e3ac0 <folio_mapping+0x60> replacing three instructions with one. [wangkefeng.wang@huawei.com: fix ubsan warnings] Link: https://lkml.kernel.org/r/2d19c48a-c550-4345-bf36-d05cd303c5de@huawei.com Link: https://lkml.kernel.org/r/20240821173914.2270383-4-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: David Hildenbrand <david@redhat.com> Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Kent Overstreet <kent.overstreet@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| 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 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.