mainlining shenanigans
598162d050
Prior to big pcluster, there was only one compressed page so it'd easy to map this. However, when big pcluster is enabled, more work needs to be done to handle multiple compressed pages. In detail, - (maptype 0) if there is only one compressed page + no need to copy inplace I/O, just map it directly what we did before; - (maptype 1) if there are more compressed pages + no need to copy inplace I/O, vmap such compressed pages instead; - (maptype 2) if inplace I/O needs to be copied, use per-CPU buffers for decompression then. Another thing is how to detect inplace decompression is feasable or not (it's still quite easy for non big pclusters), apart from the inplace margin calculation, inplace I/O page reusing order is also needed to be considered for each compressed page. Currently, if the compressed page is the xth page, it shouldn't be reused as [0 ... nrpages_out - nrpages_in + x], otherwise a full copy will be triggered. Although there are some extra optimization ideas for this, I'd like to make big pcluster work correctly first and obviously it can be further optimized later since it has nothing with the on-disk format at all. Link: https://lore.kernel.org/r/20210407043927.10623-10-xiang@kernel.org Acked-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Gao Xiang <hsiangkao@redhat.com> |
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| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
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| Kbuild | ||
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| 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.