- 04 Jun, 2020 40 commits
-
-
Baoquan He authored
Because the lowmem reserve protection of a zone can't tell anything if the zone is empty, except of adding one more line in /proc/zoneinfo. Let's remove it from that zone's showing. Signed-off-by:
Baoquan He <bhe@redhat.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200402140113.3696-4-bhe@redhat.comSigned-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
-
Baoquan He authored
When requesting memory allocation from a specific zone is not satisfied, it will fall to lower zone to try allocating memory. In this case, lower zone's ->lowmem_reserve[] will help protect its own memory resource. The higher the relevant ->lowmem_reserve[] is, the harder the upper zone can get memory from this lower zone. However, this protection mechanism should be applied to populated zone, but not an empty zone. So filling ->lowmem_reserve[] for empty zone is not necessary, and may mislead people that it's valid data in that zone. Node 2, zone DMA pages free 0 min 0 low 0 high 0 spanned 0 present 0 managed 0 protection: (0, 0, 1024, 1024) Node 2, zone DMA32 pages free 0 min 0 low 0 high 0 spanned 0 present 0 managed 0 protection: (0, 0, 1024, 1024) Node 2, zone Normal per-node stats nr_inactive_anon 0 nr_active_anon 143 nr_inactive_file 0 nr_active_file 0 nr_unevictable 0 nr_slab_reclaimable 45 nr_slab_unreclaimable 254 Here clear out zone->lowmem_reserve[] if zone is empty. Signed-off-by: -
Baoquan He authored
Patch series "improvements about lowmem_reserve and /proc/zoneinfo", v2. This patch (of 3): When people write to /proc/sys/vm/lowmem_reserve_ratio to change sysctl_lowmem_reserve_ratio[], setup_per_zone_lowmem_reserve() is called to recalculate all ->lowmem_reserve[] for each zone of all nodes as below: static void setup_per_zone_lowmem_reserve(void) { ... for_each_online_pgdat(pgdat) { for (j = 0; j < MAX_NR_ZONES; j++) { ... while (idx) { ... if (sysctl_lowmem_reserve_ratio[idx] < 1) { sysctl_lowmem_reserve_ratio[idx] = 0; lower_zone->lowmem_reserve[j] = 0; } else { ... } } } } Meanwhile, here, sysctl_lowmem_reserve_ratio[idx] will be tuned if its value is smaller than '1'. As we know, sysctl_lowmem_reserve_ratio[] is set for zone without regarding to which node it belongs to. That means the tuning will be done on all nodes, even though it has been done in the first node. And the tuning will be done too even when init_per_zone_wmark_min() calls setup_per_zone_lowmem_reserve(), where actually nobody tries to change sysctl_lowmem_reserve_ratio[]. So now move the tuning into lowmem_reserve_ratio_sysctl_handler(), to make code logic more reasonable. Signed-off-by: -
Baoquan He authored
Since commit 397dc00e ("mips: sgi-ip27: switch from DISCONTIGMEM to SPARSEMEM"), the last caller of free_bootmem_with_active_regions() was gone. Now no user calls it any more. Let's remove it. Signed-off-by:
David Hildenbrand <david@redhat.com> Acked-by:
Michal Hocko <mhocko@suse.com> Link: http://lkml.kernel.org/r/20200402143455.5145-1-bhe@redhat.comSigned-off-by:
-
Roman Gushchin authored
Currently a cma area is barely used by the page allocator because it's used only as a fallback from movable, however kswapd tries hard to make sure that the fallback path isn't used. This results in a system evicting memory and pushing data into swap, while lots of CMA memory is still available. This happens despite the fact that alloc_contig_range is perfectly capable of moving any movable allocations out of the way of an allocation. To effectively use the cma area let's alter the rules: if the zone has more free cma pages than the half of total free pages in the zone, use cma pageblocks first and fallback to movable blocks in the case of failure. [guro@fb.com: ifdef the cma-specific code] Link: http://lkml.kernel.org/r/20200311225832.GA178154@carbon.DHCP.thefacebook.comCo-developed-by:
Rik van Riel <riel@surriel.com> Signed-off-by:
Roman Gushchin <guro@fb.com> Signed-off-by:
Vlastimil Babka <vbabka@suse.cz> Acked-by:
Minchan Kim <minchan@kernel.org> Cc: Qian Cai <cai@lca.pw> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Joonsoo Kim <js1304@gmail.com> Link: http://lkml.kernel.org/r/20200306150102.3e77354b@imladris.surriel.comSigned-off-by:
-
Wei Yang authored
We share similar code in check_[new|free]_page_bad() to get the page's bad reason. Let's extract it and reduce code duplication. Signed-off-by:
Wei Yang <richard.weiyang@gmail.com> Signed-off-by:
-
Wei Yang authored
free_pages_check() is the counterpart of check_new_page(). Rename it to use the same naming convention. Signed-off-by:
-
Wei Yang authored
free_pages_check_bad() is the counterpart of check_new_page_bad(). Rename it to use the same naming convention. Signed-off-by:
-
Wei Yang authored
After commit 5b57b8f2 ("mm/debug.c: always print flags in dump_page()"), page->flags is always printed for a bad page. It is not necessary to have bad_flags any more. Suggested-by:
Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by:
-
Wei Yang authored
Patch series "mm/page_alloc.c: cleanup on check page", v3. This patchset does some cleanup related to check page. 1. Remove unnecessary bad_reason assignment 2. Remove bad_flags to bad_page() 3. Rename function for naming convention 4. Extract common part to check page Thanks for suggestions from David Rientjes and Anshuman Khandual. This patch (of 5): Since function returns directly, bad_[reason|flags] is not used any where. And move this to the first. This is a following cleanup for commit e570f56c ("mm: check_new_page_bad() directly returns in __PG_HWPOISON case") Signed-off-by:
-
Mike Rapoport authored
To reflect the updates to free_area_init() family of functions. Signed-off-by:
Mike Rapoport <rppt@linux.ibm.com> Signed-off-by:
-
Mike Rapoport authored
find_min_pfn_with_active_regions() calls find_min_pfn_for_node() with nid parameter set to MAX_NUMNODES. This makes the find_min_pfn_for_node() traverse all memblock memory regions although the first PFN in the system can be easily found with memblock_start_of_DRAM(). Use memblock_start_of_DRAM() in find_min_pfn_with_active_regions() and drop now unused find_min_pfn_for_node(). Signed-off-by:
-
Mike Rapoport authored
free_area_init_node() now always uses memblock info and the zone PFN limits so it does not need the backwards compatibility functions to calculate the zone spanned and absent pages. The removal of the compat_ versions of zone_{abscent,spanned}_pages_in_node() in turn, makes zone_size and zhole_size parameters unused. The node_start_pfn is determined by get_pfn_range_for_nid(), so there is no need to pass it to free_area_init_node(). As a result, the only required parameter to free_area_init_node() is the node ID, all the rest are removed along with no longer used compat_zone_{abscent,spanned}_pages_in_node() helpers. Signed-off-by: -
Mike Rapoport authored
free_area_init_node() is only used by x86 to initialize a memory-less nodes. Make its name reflect this and drop all the function parameters except node ID as they are anyway zero. Signed-off-by:
-
Mike Rapoport authored
Some architectures (e.g. ARC) have the ZONE_HIGHMEM zone below the ZONE_NORMAL. Allowing free_area_init() parse max_zone_pfn array even it is sorted in descending order allows using free_area_init() on such architectures. Add top -> down traversal of max_zone_pfn array in free_area_init() and use the latter in ARC node/zone initialization. [rppt@kernel.org: ARC fix] Link: http://lkml.kernel.org/r/20200504153901.GM14260@kernel.org [rppt@linux.ibm.com: arc: free_area_init(): take into account PAE40 mode] Link: http://lkml.kernel.org/r/20200507205900.GH683243@linux.ibm.com [akpm@linux-foundation.org: declare arch_has_descending_max_zone_pfns()] Signed-off-by:
-
Mike Rapoport authored
The memmap_init() function was made to iterate over memblock regions and as the result the early_pfn_in_nid() function became obsolete. Since CONFIG_NODES_SPAN_OTHER_NODES is only used to pick a stub or a real implementation of early_pfn_in_nid(), it is also not needed anymore. Remove both early_pfn_in_nid() and the CONFIG_NODES_SPAN_OTHER_NODES. Co-developed-by:
Hoan Tran <Hoan@os.amperecomputing.com> Signed-off-by:
-
Baoquan He authored
When called during boot the memmap_init_zone() function checks if each PFN is valid and actually belongs to the node being initialized using early_pfn_valid() and early_pfn_in_nid(). Each such check may cost up to O(log(n)) where n is the number of memory banks, so for large amount of memory overall time spent in early_pfn*() becomes substantial. Since the information is anyway present in memblock, we can iterate over memblock memory regions in memmap_init() and only call memmap_init_zone() for PFN ranges that are know to be valid and in the appropriate node. [cai@lca.pw: fix a compilation warning from Clang] Link: http://lkml.kernel.org/r/CF6E407F-17DC-427C-8203-21979FB882EF@lca.pw [bhe@redhat.com: fix the incorrect hole in fast_isolate_freepages()] Link: http://lkml.kernel.org/r/8C537EB7-85EE-4DCF-943E-3CC0ED0DF56D@lca.pw Link: http://lkml.kernel.org/r/20200521014407.29690-1-bhe@redhat.comSigned-off-by:
-
Mike Rapoport authored
free_area_init() only requires the definition of maximal PFN for each of the supported zone rater than calculation of actual zone sizes and the sizes of the holes between the zones. After removal of CONFIG_HAVE_MEMBLOCK_NODE_MAP the free_area_init() is available to all architectures. Using this function instead of free_area_init_node() simplifies the zone detection. Signed-off-by:
-
Mike Rapoport authored
free_area_init() only requires the definition of maximal PFN for each of the supported zone rater than calculation of actual zone sizes and the sizes of the holes between the zones. After removal of CONFIG_HAVE_MEMBLOCK_NODE_MAP the free_area_init() is available to all architectures. Using this function instead of free_area_init_node() simplifies the zone detection. Signed-off-by:
-
Mike Rapoport authored
free_area_init() only requires the definition of maximal PFN for each of the supported zone rater than calculation of actual zone sizes and the sizes of the holes between the zones. After removal of CONFIG_HAVE_MEMBLOCK_NODE_MAP the free_area_init() is available to all architectures. Using this function instead of free_area_init_node() simplifies the zone detection. Signed-off-by:
-
Mike Rapoport authored
free_area_init() only requires the definition of maximal PFN for each of the supported zone rater than calculation of actual zone sizes and the sizes of the holes between the zones. After removal of CONFIG_HAVE_MEMBLOCK_NODE_MAP the free_area_init() is available to all architectures. Using this function instead of free_area_init_node() simplifies the zone detection. Signed-off-by:
-
Mike Rapoport authored
free_area_init() only requires the definition of maximal PFN for each of the supported zone rater than calculation of actual zone sizes and the sizes of the holes between the zones. After removal of CONFIG_HAVE_MEMBLOCK_NODE_MAP the free_area_init() is available to all architectures. Using this function instead of free_area_init_node() simplifies the zone detection. Signed-off-by:
-
Mike Rapoport authored
The free_area_init() function only requires the definition of maximal PFN for each of the supported zone rater than calculation of actual zone sizes and the sizes of the holes between the zones. After removal of CONFIG_HAVE_MEMBLOCK_NODE_MAP the free_area_init() is available to all architectures. Using this function instead of free_area_init_node() simplifies the zone detection. Signed-off-by:
-
Mike Rapoport authored
The free_area_init() function only requires the definition of maximal PFN for each of the supported zone rater than calculation of actual zone sizes and the sizes of the holes between the zones. After removal of CONFIG_HAVE_MEMBLOCK_NODE_MAP the free_area_init() is available to all architectures. Using this function instead of free_area_init_node() simplifies the zone detection. Signed-off-by:
Catalin Marinas <catalin.marinas@arm.com> Cc: Baoquan He <bhe@redhat.com> Cc: Brian Cain <bcain@codeaurora.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greentime Hu <green.hu@gmail.com> Cc: Greg Ungerer <gerg@linux-m68k.org> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: Guo Ren <guoren@kernel.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Ley Foon Tan <ley.foon.tan@intel.com> Cc: Mark Salter <msalter@redhat.com> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Simek <monstr@monstr.eu> Cc: Nick Hu <nickhu@andestech.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Weinberger <richard@nod.at> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Stafford Horne <shorne@gmail.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Link: http://lkml.kernel.org/r/20200412194859.12663-9-rppt@kernel.orgSigned-off-by:
-
Mike Rapoport authored
free_area_init() only requires the definition of maximal PFN for each of the supported zone rater than calculation of actual zone sizes and the sizes of the holes between the zones. After removal of CONFIG_HAVE_MEMBLOCK_NODE_MAP the free_area_init() is available to all architectures. Using this function instead of free_area_init_node() simplifies the zone detection. Signed-off-by:
-
Mike Rapoport authored
free_area_init() only requires the definition of maximal PFN for each of the supported zone rater than calculation of actual zone sizes and the sizes of the holes between the zones. After removal of CONFIG_HAVE_MEMBLOCK_NODE_MAP the free_area_init() is available to all architectures. Using this function instead of free_area_init_node() simplifies the zone detection. Signed-off-by:
-
Mike Rapoport authored
free_area_init() has effectively became a wrapper for free_area_init_nodes() and there is no point of keeping it. Still free_area_init() name is shorter and more general as it does not imply necessity to initialize multiple nodes. Rename free_area_init_nodes() to free_area_init(), update the callers and drop old version of free_area_init(). Signed-off-by:
-
Mike Rapoport authored
Currently, architectures that use free_area_init() to initialize memory map and node and zone structures need to calculate zone and hole sizes. We can use free_area_init_nodes() instead and let it detect the zone boundaries while the architectures will only have to supply the possible limits for the zones. Signed-off-by:
-
Mike Rapoport authored
CONFIG_HAVE_MEMBLOCK_NODE_MAP is used to differentiate initialization of nodes and zones structures between the systems that have region to node mapping in memblock and those that don't. Currently all the NUMA architectures enable this option and for the non-NUMA systems we can presume that all the memory belongs to node 0 and therefore the compile time configuration option is not required. The remaining few architectures that use DISCONTIGMEM without NUMA are easily updated to use memblock_add_node() instead of memblock_add() and thus have proper correspondence of memblock regions to NUMA nodes. Still, free_area_init_node() must have a backward compatible version because its semantics with and without CONFIG_HAVE_MEMBLOCK_NODE_MAP is different. Once all the architectures will use the new semantics, the entire compatibility layer can be dropped. To avoid addition of extra run time memory to store node id for architectures that keep memblock but have only a single node, the node id field of the memblock_region is guarded by CONFIG_NEED_MULTIPLE_NODES and the corresponding accessors presume that in those cases it is always 0. Signed-off-by:
-
Mike Rapoport authored
early_pfn_to_nid() and its helper __early_pfn_to_nid() are spread around include/linux/mm.h, include/linux/mmzone.h and mm/page_alloc.c. Drop unused stub for __early_pfn_to_nid() and move its actual generic implementation close to its users. Signed-off-by:
-
Mike Rapoport authored
Patch series "mm: rework free_area_init*() funcitons". After the discussion [1] about removal of CONFIG_NODES_SPAN_OTHER_NODES and CONFIG_HAVE_MEMBLOCK_NODE_MAP options, I took it a bit further and updated the node/zone initialization. Since all architectures have memblock, it is possible to use only the newer version of free_area_init_node() that calculates the zone and node boundaries based on memblock node mapping and architectural limits on possible zone PFNs. The architectures that still determined zone and hole sizes can be switched to the generic code and the old code that took those zone and hole sizes can be simply removed. And, since it all started from the removal of CONFIG_NODES_SPAN_OTHER_NODES, the memmap_init() is now updated to iterate over memblocks and so it does not need to perform early_pfn_to_nid() query for every PFN. [1] https://lore.kernel.org/lkml/1585420282-25630-1-git-send-email-Hoan@os.amperecomputing.com This patch (of 21): There are several places in the code that directly dereference memblock_region.nid despite this field being defined only when CONFIG_HAVE_MEMBLOCK_NODE_MAP=y. Replace these with calls to memblock_get_region_nid() to improve code robustness and to avoid possible breakage when CONFIG_HAVE_MEMBLOCK_NODE_MAP will be removed. Signed-off-by:
-
Michal Hocko authored
It seems that the existing documentation is not explicit about the expected usage and potential risks enough. While it is calls out that users have to free memory when using this flag it is not really apparent that users have to careful to not deplete memory reserves and that they should implement some sort of throttling wrt. freeing process. This is partly based on Neil's explanation [1]. Let's also call out that a pre allocated pool allocator should be considered. [1] http://lkml.kernel.org/r/877dz0yxoa.fsf@notabene.neil.brown.name [akpm@linux-foundation.org: coding style fixes] [mhocko@kernel.org: update] Link: http://lkml.kernel.org/r/20200406070137.GC19426@dhcp22.suse.czSigned-off-by:
-
Daniel Axtens authored
The memcmp KASAN self-test fails on a kernel with both KASAN and FORTIFY_SOURCE. When FORTIFY_SOURCE is on, a number of functions are replaced with fortified versions, which attempt to check the sizes of the operands. However, these functions often directly invoke __builtin_foo() once they have performed the fortify check. Using __builtins may bypass KASAN checks if the compiler decides to inline it's own implementation as sequence of instructions, rather than emit a function call that goes out to a KASAN-instrumented implementation. Why is only memcmp affected? ============================ Of the string and string-like functions that kasan_test tests, only memcmp is replaced by an inline sequence of instructions in my testing on x86 with gcc version 9.2.1 20191008 (Ubuntu 9.2.1-9ubuntu2). I believe this is due to compiler heuristics. For example, if I annotate kmalloc calls with the alloc_size annotation (and disable some fortify compile-time checking!), the compiler will replace every memset except the one in kmalloc_uaf_memset with inline instructions. (I have some WIP patches to add this annotation.) Does this affect other functions in string.h? ============================================= Yes. Anything that uses __builtin_* rather than __real_* could be affected. This looks like: - strncpy - strcat - strlen - strlcpy maybe, under some circumstances? - strncat under some circumstances - memset - memcpy - memmove - memcmp (as noted) - memchr - strcpy Whether a function call is emitted always depends on the compiler. Most bugs should get caught by FORTIFY_SOURCE, but the missed memcmp test shows that this is not always the case. Isn't FORTIFY_SOURCE disabled with KASAN? ========================================- The string headers on all arches supporting KASAN disable fortify with kasan, but only when address sanitisation is _also_ disabled. For example from x86: #if defined(CONFIG_KASAN) && !defined(__SANITIZE_ADDRESS__) /* * For files that are not instrumented (e.g. mm/slub.c) we * should use not instrumented version of mem* functions. */ #define memcpy(dst, src, len) __memcpy(dst, src, len) #define memmove(dst, src, len) __memmove(dst, src, len) #define memset(s, c, n) __memset(s, c, n) #ifndef __NO_FORTIFY #define __NO_FORTIFY /* FORTIFY_SOURCE uses __builtin_memcpy, etc. */ #endif #endif This comes from commit 6974f0c4 ("include/linux/string.h: add the option of fortified string.h functions"), and doesn't work when KASAN is enabled and the file is supposed to be sanitised - as with test_kasan.c I'm pretty sure this is not wrong, but not as expansive it should be: * we shouldn't use __builtin_memcpy etc in files where we don't have instrumentation - it could devolve into a function call to memcpy, which will be instrumented. Rather, we should use __memcpy which by convention is not instrumented. * we also shouldn't be using __builtin_memcpy when we have a KASAN instrumented file, because it could be replaced with inline asm that will not be instrumented. What is correct behaviour? ========================== Firstly, there is some overlap between fortification and KASAN: both provide some level of _runtime_ checking. Only fortify provides compile-time checking. KASAN and fortify can pick up different things at runtime: - Some fortify functions, notably the string functions, could easily be modified to consider sub-object sizes (e.g. members within a struct), and I have some WIP patches to do this. KASAN cannot detect these because it cannot insert poision between members of a struct. - KASAN can detect many over-reads/over-writes when the sizes of both operands are unknown, which fortify cannot. So there are a couple of options: 1) Flip the test: disable fortify in santised files and enable it in unsanitised files. This at least stops us missing KASAN checking, but we lose the fortify checking. 2) Make the fortify code always call out to real versions. Do this only for KASAN, for fear of losing the inlining opportunities we get from __builtin_*. (We can't use kasan_check_{read,write}: because the fortify functions are _extern inline_, you can't include _static_ inline functions without a compiler warning. kasan_check_{read,write} are static inline so we can't use them even when they would otherwise be suitable.) Take approach 2 and call out to real versions when KASAN is enabled. Use __underlying_foo to distinguish from __real_foo: __real_foo always refers to the kernel's implementation of foo, __underlying_foo could be either the kernel implementation or the __builtin_foo implementation. This is sometimes enough to make the memcmp test succeed with FORTIFY_SOURCE enabled. It is at least enough to get the function call into the module. One more fix is needed to make it reliable: see the next patch. Fixes: 6974f0c4 ("include/linux/string.h: add the option of fortified string.h functions") Signed-off-by:
Daniel Axtens <dja@axtens.net> Signed-off-by:
David Gow <davidgow@google.com> Reviewed-by:
Dmitry Vyukov <dvyukov@google.com> Cc: Daniel Micay <danielmicay@gmail.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Link: http://lkml.kernel.org/r/20200423154503.5103-3-dja@axtens.netSigned-off-by:
-
Daniel Axtens authored
Patch series "Fix some incompatibilites between KASAN and FORTIFY_SOURCE", v4. 3 KASAN self-tests fail on a kernel with both KASAN and FORTIFY_SOURCE: memchr, memcmp and strlen. When FORTIFY_SOURCE is on, a number of functions are replaced with fortified versions, which attempt to check the sizes of the operands. However, these functions often directly invoke __builtin_foo() once they have performed the fortify check. The compiler can detect that the results of these functions are not used, and knows that they have no other side effects, and so can eliminate them as dead code. Why are only memchr, memcmp and strlen affected? ================================================ Of string and string-like functions, kasan_test tests: * strchr -> not affected, no fortified version * strrchr -> likewise * strcmp -> likewise * strncmp -> likewise * strnlen -> not affected, the fortify source implementation calls the underlying strnlen implementation which is instrumented, not a builtin * strlen -> affected, the fortify souce implementation calls a __builtin version which the compiler can determine is dead. * memchr -> likewise * memcmp -> likewise * memset -> not affected, the compiler knows that memset writes to its first argument and therefore is not dead. Why does this not affect the functions normally? ================================================ In string.h, these functions are not marked as __pure, so the compiler cannot know that they do not have side effects. If relevant functions are marked as __pure in string.h, we see the following warnings and the functions are elided: lib/test_kasan.c: In function `kasan_memchr': lib/test_kasan.c:606:2: warning: statement with no effect [-Wunused-value] memchr(ptr, '1', size + 1); ^~~~~~~~~~~~~~~~~~~~~~~~~~ lib/test_kasan.c: In function `kasan_memcmp': lib/test_kasan.c:622:2: warning: statement with no effect [-Wunused-value] memcmp(ptr, arr, size+1); ^~~~~~~~~~~~~~~~~~~~~~~~ lib/test_kasan.c: In function `kasan_strings': lib/test_kasan.c:645:2: warning: statement with no effect [-Wunused-value] strchr(ptr, '1'); ^~~~~~~~~~~~~~~~ ... This annotation would make sense to add and could be added at any point, so the behaviour of test_kasan.c should change. The fix ======= Make all the functions that are pure write their results to a global, which makes them live. The strlen and memchr tests now pass. The memcmp test still fails to trigger, which is addressed in the next patch. [dja@axtens.net: drop patch 3] Link: http://lkml.kernel.org/r/20200424145521.8203-2-dja@axtens.net Fixes: 0c96350a ("lib/test_kasan.c: add tests for several string/memory API functions") Signed-off-by: -
John Hubbard authored
Instead of scattering these assertions across the drivers, do this assertion inside the core of get_user_pages_fast*() functions. That also includes pin_user_pages_fast*() routines. Add a might_lock_read(mmap_sem) call to internal_get_user_pages_fast(). Suggested-by:
Matthew Wilcox <willy@infradead.org> Signed-off-by:
John Hubbard <jhubbard@nvidia.com> Signed-off-by:
-
John Hubbard authored
This code was using get_user_pages*(), in a "Case 2" scenario (DMA/RDMA), using the categorization from [1]. That means that it's time to convert the get_user_pages*() + put_page() calls to pin_user_pages*() + unpin_user_pages() calls. There is some helpful background in [2]: basically, this is a small part of fixing a long-standing disconnect between pinning pages, and file systems' use of those pages. [1] Documentation/core-api/pin_user_pages.rst [2] "Explicit pinning of user-space pages": https://lwn.net/Articles/807108/Signed-off-by:Chris Wilson <chris@chris-wilson.co.uk> Cc: Souptick Joarder <jrdr.linux@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: "Joonas Lahtinen" <joonas.lahtinen@linux.intel.com> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: David Airlie <airlied@linux.ie> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Matthew Auld <matthew.auld@intel.com> Link: http://lkml.kernel.org/r/20200519002124.2025955-5-jhubbard@nvidia.comSigned-off-by:
-
John Hubbard authored
This is the FOLL_PIN equivalent of __get_user_pages_fast(), except with a more descriptive name, and gup_flags instead of a boolean "write" in the argument list. Signed-off-by:
-
John Hubbard authored
There were two nearly identical sets of code for gup_fast() style of walking the page tables with interrupts disabled. This has lead to the usual maintenance problems that arise from having duplicated code. There is already a core internal routine in gup.c for gup_fast(), so just enhance it very slightly: allow skipping the fall-back to "slow" (regular) get_user_pages(), via the new FOLL_FAST_ONLY flag. Then, just call internal_get_user_pages_fast() from __get_user_pages_fast(), and adjust the API to match pre-existing API behavior. There is a change in behavior from this refactoring: the nested form of interrupt disabling is used in all gup_fast() variants now. That's because there is only one place that interrupt disabling for page walking is done, and so the safer form is required. This should, if anything, eliminate possible (rare) bugs, because the non-nested form of enabling interrupts was fragile at best. [jhubbard@nvidia.com: fixup] Link: http://lkml.kernel.org/r/20200521233841.1279742-1-jhubbard@nvidia.comSigned-off-by:
-
John Hubbard authored
Patch series "mm/gup, drm/i915: refactor gup_fast, convert to pin_user_pages()", v2. In order to convert the drm/i915 driver from get_user_pages() to pin_user_pages(), a FOLL_PIN equivalent of __get_user_pages_fast() was required. That led to refactoring __get_user_pages_fast(), with the following goals: 1) As above: provide a pin_user_pages*() routine for drm/i915 to call, in place of __get_user_pages_fast(), 2) Get rid of the gup.c duplicate code for walking page tables with interrupts disabled. This duplicate code is a minor maintenance problem anyway. 3) Make it easy for an upcoming patch from Souptick, which aims to convert __get_user_pages_fast() to use a gup_flags argument, instead of a bool writeable arg. Also, if this series looks good, we can ask Souptick to change the name as well, to whatever the consensus is. My initial recommendation is: get_user_pages_fast_only(), to match the new pin_user_pages_only(). This patch (of 4): This is in order to avoid a forward declaration of internal_get_user_pages_fast(), in the next patch. This is code movement only--all generated code should be identical. Signed-off-by:
-
Shakeel Butt authored
Currently reading memory.numa_stat traverses the underlying memcg tree multiple times to accumulate the stats to present the hierarchical view of the memcg tree. However the kernel already maintains the hierarchical view of the stats and use it in memory.stat. Just use the same mechanism in memory.numa_stat as well. I ran a simple benchmark which reads root_mem_cgroup's memory.numa_stat file in the presense of 10000 memcgs. The results are: Without the patch: $ time cat /dev/cgroup/memory/memory.numa_stat > /dev/null real 0m0.700s user 0m0.001s sys 0m0.697s With the patch: $ time cat /dev/cgroup/memory/memory.numa_stat > /dev/null real 0m0.001s user 0m0.001s sys 0m0.000s [akpm@linux-foundation.org: avoid forcing out-of-line code generation] Signed-off-by:
Shakeel Butt <shakeelb@google.com> Signed-off-by:
Johannes Weiner <hannes@cmpxchg.org> Cc: Roman Gushchin <guro@fb.com> Cc: Michal Hocko <mhocko@kernel.org> Link: http://lkml.kernel.org/r/20200304022058.248270-1-shakeelb@google.comSigned-off-by:
-
