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A mirror of the official Linux kernel repository just in case
77292bb8ca
while sg_nents is 1, which is always true for the current kernel as the only user - zswap is this case, we might have a chance to remove memcpy, thus improve the performance. Though sg_nents is 1, its buffer might cross two pages. If those pages are highmem, we have no cheap way to map them to contiguous virtual address because kmap doesn't support more than one page (kmap single higmem page could be still expensive for tlb) and vmap is expensive. So we also test and enure page is not highmem in order to safely use page_to_virt before removing the memcpy. The good news is that in the most majority of cases, we are lowmem, and we are always lowmem in those modern and popular hardware. Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Barry Song <v-songbaohua@oppo.com> Tested-by: Chengming Zhou <zhouchengming@bytedance.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> |
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| 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 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.