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130e8e09e2
Currently we reach inside the list_head. This is a violation of the layer of abstraction provided by the list_head. It makes the code fragile. More importantly it makes the code wicked hard to understand. The code reaches into the list_head structure to counteract the fact that the list _may_ have been changed during slob_page_alloc(). Instead of this we can add a return parameter to slob_page_alloc() to signal that the list was modified (list_del() called with page->lru to remove page from the freelist). This code is concerned with an optimisation that counters the tendency for first fit allocation algorithm to fragment memory into many small chunks at the front of the memory pool. Since the page is only removed from the list when an allocation uses _all_ the remaining memory in the page then in this special case fragmentation does not occur and we therefore do not need the optimisation. Add a return parameter to slob_page_alloc() to signal that the allocation used up the whole page and that the page was removed from the free list. After calling slob_page_alloc() check the return value just added and only attempt optimisation if the page is still on the list. Use list_head API instead of reaching into the list_head structure to check if sp is at the front of the list. Link: http://lkml.kernel.org/r/20190402230545.2929-3-tobin@kernel.org Signed-off-by: Tobin C. Harding <tobin@kernel.org> Acked-by: Christoph Lameter <cl@linux.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Roman Gushchin <guro@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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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 | ||
| CREDITS | ||
| Kbuild | ||
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| 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.