user/sven/linux.git/include/linux/page_ext.h, branch v5.9.8

mm, page_owner: rename flag indicating that page is allocated

2019-10-14T22:04:00Z

Commit 37389167a281 ("mm, page_owner: keep owner info when freeing the page") has introduced a flag PAGE_EXT_OWNER_ACTIVE to indicate that page is tracked as being allocated. Kirril suggested naming it PAGE_EXT_OWNER_ALLOCATED to make it more clear, as "active is somewhat loaded term for a page". Link: http://lkml.kernel.org/r/20190930122916.14969-4-vbabka@suse.cz Signed-off-by: Vlastimil Babka Suggested-by: Kirill A. Shutemov Cc: Andrey Ryabinin Cc: Dmitry Vyukov Cc: Kirill A. Shutemov Cc: Walter Wu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm, page_owner: fix off-by-one error in __set_page_owner_handle()

2019-10-14T22:04:00Z

Patch series "followups to debug_pagealloc improvements through page_owner", v3. These are followups to [1] which made it to Linus meanwhile. Patches 1 and 3 are based on Kirill's review, patch 2 on KASAN request [2]. It would be nice if all of this made it to 5.4 with [1] already there (or at least Patch 1). This patch (of 3): As noted by Kirill, commit 7e2f2a0cd17c ("mm, page_owner: record page owner for each subpage") has introduced an off-by-one error in __set_page_owner_handle() when looking up page_ext for subpages. As a result, the head page page_owner info is set twice, while for the last tail page, it's not set at all. Fix this and also make the code more efficient by advancing the page_ext pointer we already have, instead of calling lookup_page_ext() for each subpage. Since the full size of struct page_ext is not known at compile time, we can't use a simple page_ext++ statement, so introduce a page_ext_next() inline function for that. Link: http://lkml.kernel.org/r/20190930122916.14969-2-vbabka@suse.cz Fixes: 7e2f2a0cd17c ("mm, page_owner: record page owner for each subpage") Signed-off-by: Vlastimil Babka Reported-by: Kirill A. Shutemov Reported-by: Miles Chen Acked-by: Kirill A. Shutemov Cc: Andrey Ryabinin Cc: Dmitry Vyukov Cc: Walter Wu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm, page_owner: keep owner info when freeing the page

2019-09-24T22:54:08Z

For debugging purposes it might be useful to keep the owner info even after page has been freed, and include it in e.g. dump_page() when detecting a bad page state. For that, change the PAGE_EXT_OWNER flag meaning to "page owner info has been set at least once" and add new PAGE_EXT_OWNER_ACTIVE for tracking whether page is supposed to be currently tracked allocated or free. Adjust dump_page() accordingly, distinguishing free and allocated pages. In the page_owner debugfs file, keep printing only allocated pages so that existing scripts are not confused, and also because free pages are irrelevant for the memory statistics or leak detection that's the typical use case of the file, anyway. Link: http://lkml.kernel.org/r/20190820131828.22684-4-vbabka@suse.cz Signed-off-by: Vlastimil Babka Cc: Kirill A. Shutemov Cc: Matthew Wilcox Cc: Mel Gorman Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm, debug_pagealloc: use a page type instead of page_ext flag

2019-07-12T18:05:43Z

When debug_pagealloc is enabled, we currently allocate the page_ext array to mark guard pages with the PAGE_EXT_DEBUG_GUARD flag. Now that we have the page_type field in struct page, we can use that instead, as guard pages are neither PageSlab nor mapped to userspace. This reduces memory overhead when debug_pagealloc is enabled and there are no other features requiring the page_ext array. Link: http://lkml.kernel.org/r/20190603143451.27353-4-vbabka@suse.cz Signed-off-by: Vlastimil Babka Cc: Joonsoo Kim Cc: Matthew Wilcox Cc: "Kirill A. Shutemov" Cc: Mel Gorman Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/page_ext.c: constify lookup_page_ext() argument

2018-08-17T23:20:28Z

lookup_page_ext() finds 'struct page_ext' for a given page. It requires only read access to the given struct page. Current implemnentation takes 'struct page *' as an argument. It makes compiler complain when 'const struct page *' passed. Change the argument to 'const struct page *'. Link: http://lkml.kernel.org/r/20180531135457.20167-3-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov Reviewed-by: Andrew Morton Cc: Vinayak Menon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

include/linux/page_ext.h: drop definition of unused PAGE_EXT_DEBUG_POISON

2018-08-17T23:20:28Z

After commit bd33ef368135 ("mm: enable page poisoning early at boot") PAGE_EXT_DEBUG_POISON is not longer used. Remove it. Link: http://lkml.kernel.org/r/20180531135457.20167-2-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov Reviewed-by: Vinayak Menon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02T10:10:55Z

Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart Reviewed-by: Philippe Ombredanne Reviewed-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

mm/page_owner: don't define fields on struct page_ext by hard-coding

2016-10-08T01:46:27Z

There is a memory waste problem if we define field on struct page_ext by hard-coding. Entry size of struct page_ext includes the size of those fields even if it is disabled at runtime. Now, extra memory request at runtime is possible so page_owner don't need to define it's own fields by hard-coding. This patch removes hard-coded define and uses extra memory for storing page_owner information in page_owner. Most of code are just mechanical changes. Link: http://lkml.kernel.org/r/1471315879-32294-7-git-send-email-iamjoonsoo.kim@lge.com Signed-off-by: Joonsoo Kim Acked-by: Vlastimil Babka Cc: Minchan Kim Cc: Michal Hocko Cc: Sergey Senozhatsky Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/page_ext: support extra space allocation by page_ext user

2016-10-08T01:46:27Z

Until now, if some page_ext users want to use it's own field on page_ext, it should be defined in struct page_ext by hard-coding. It has a problem that wastes memory in following situation. struct page_ext { #ifdef CONFIG_A int a; #endif #ifdef CONFIG_B int b; #endif }; Assume that kernel is built with both CONFIG_A and CONFIG_B. Even if we enable feature A and doesn't enable feature B at runtime, each entry of struct page_ext takes two int rather than one int. It's undesirable result so this patch tries to fix it. To solve above problem, this patch implements to support extra space allocation at runtime. When need() callback returns true, it's extra memory requirement is summed to entry size of page_ext. Also, offset for each user's extra memory space is returned. With this offset, user can use this extra space and there is no need to define needed field on page_ext by hard-coding. This patch only implements an infrastructure. Following patch will use it for page_owner which is only user having it's own fields on page_ext. Link: http://lkml.kernel.org/r/1471315879-32294-6-git-send-email-iamjoonsoo.kim@lge.com Signed-off-by: Joonsoo Kim Acked-by: Vlastimil Babka Cc: Minchan Kim Cc: Michal Hocko Cc: Sergey Senozhatsky Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/page_owner: use stackdepot to store stacktrace

2016-07-26T23:19:19Z

Currently, we store each page's allocation stacktrace on corresponding page_ext structure and it requires a lot of memory. This causes the problem that memory tight system doesn't work well if page_owner is enabled. Moreover, even with this large memory consumption, we cannot get full stacktrace because we allocate memory at boot time and just maintain 8 stacktrace slots to balance memory consumption. We could increase it to more but it would make system unusable or change system behaviour. To solve the problem, this patch uses stackdepot to store stacktrace. It obviously provides memory saving but there is a drawback that stackdepot could fail. stackdepot allocates memory at runtime so it could fail if system has not enough memory. But, most of allocation stack are generated at very early time and there are much memory at this time. So, failure would not happen easily. And, one failure means that we miss just one page's allocation stacktrace so it would not be a big problem. In this patch, when memory allocation failure happens, we store special stracktrace handle to the page that is failed to save stacktrace. With it, user can guess memory usage properly even if failure happens. Memory saving looks as following. (4GB memory system with page_owner) (before the patch -> after the patch) static allocation: 92274688 bytes -> 25165824 bytes dynamic allocation after boot + kernel build: 0 bytes -> 327680 bytes total: 92274688 bytes -> 25493504 bytes 72% reduction in total. Note that implementation looks complex than someone would imagine because there is recursion issue. stackdepot uses page allocator and page_owner is called at page allocation. Using stackdepot in page_owner could re-call page allcator and then page_owner. That is a recursion. To detect and avoid it, whenever we obtain stacktrace, recursion is checked and page_owner is set to dummy information if found. Dummy information means that this page is allocated for page_owner feature itself (such as stackdepot) and it's understandable behavior for user. [iamjoonsoo.kim@lge.com: mm-page_owner-use-stackdepot-to-store-stacktrace-v3] Link: http://lkml.kernel.org/r/1464230275-25791-6-git-send-email-iamjoonsoo.kim@lge.com Link: http://lkml.kernel.org/r/1466150259-27727-7-git-send-email-iamjoonsoo.kim@lge.com Link: http://lkml.kernel.org/r/1464230275-25791-6-git-send-email-iamjoonsoo.kim@lge.com Signed-off-by: Joonsoo Kim Acked-by: Vlastimil Babka Acked-by: Michal Hocko Cc: Mel Gorman Cc: Minchan Kim Cc: Alexander Potapenko Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds