- 05 Jun, 2020 40 commits
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Arnd Bergmann authored
Clang normally does not warn about certain issues in inline functions when it only happens in an eliminated code path. However if something else goes wrong, it does tend to complain about the definition of hweight_long() on 32-bit targets: include/linux/bitops.h:75:41: error: shift count >= width of type [-Werror,-Wshift-count-overflow] return sizeof(w) == 4 ? hweight32(w) : hweight64(w); ^~~~~~~~~~~~ include/asm-generic/bitops/const_hweight.h:29:49: note: expanded from macro 'hweight64' define hweight64(w) (__builtin_constant_p(w) ? __const_hweight64(w) : __arch_hweight64(w)) ^~~~~~~~~~~~~~~~~~~~ include/asm-generic/bitops/const_hweight.h:21:76: note: expanded from macro '__const_hweight64' define __const_hweight64(w) (__const_hweight32(w) + __const_hweight32((w) >> 32)) ^ ~~ include/asm-generic/bitops/const_hweight.h:20:49: note: expanded from macro '__const_hweight32' define __const_hweight32(w) (__const_hweight16(w) + __const_hweight16((w) >> 16)) ^ include/asm-generic/bitops/const_hweight.h:19:72: note: expanded from macro '__const_hweight16' define __const_hweight16(w) (__const_hweight8(w) + __const_hweight8((w) >> 8 )) ^ include/asm-generic/bitops/const_hweight.h:12:9: note: expanded from macro '__const_hweight8' (!!((w) & (1ULL << 2))) + \ Adding an explicit cast to __u64 avoids that warning and makes it easier to read other output. Signed-off-by:Arnd Bergmann <arnd@arndb.de> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Acked-by:
Christian Brauner <christian.brauner@ubuntu.com> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Nick Desaulniers <ndesaulniers@google.com> Link: http://lkml.kernel.org/r/20200505135513.65265-1-arnd@arndb.deSigned-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Jesse Brandeburg authored
Test some bit clears/sets to make sure assembly doesn't change, and that the set_bit and clear_bit functions work and don't cause sparse warnings. Instruct Kbuild to build this file with extra warning level -Wextra, to catch new issues, and also doesn't hurt to build with C=1. This was used to test changes to arch/x86/include/asm/bitops.h. In particular, sparse (C=1) was very concerned when the last bit before a natural boundary, like 7, or 31, was being tested, as this causes sign extension (0xffffff7f) for instance when clearing bit 7. Recommended usage: make defconfig scripts/config -m CONFIG_TEST_BITOPS make modules_prepare make C=1 W=1 lib/test_bitops.ko objdump -S -d lib/test_bitops.ko insmod lib/test_bitops.ko rmmod lib/test_bitops.ko <check dmesg>, there should be no compiler/sparse warnings and no error messages in log. Link: http://lkml.kernel.org/r/20200310221747.2848474-2-jesse.brandeburg@intel.comSigned-off-by:
Jesse Brandeburg <jesse.brandeburg@intel.com> Reviewed-by:
Andy Shevchenko <andriy.shevchenko@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> CcL Ingo Molnar <mingo@redhat.com> Signed-off-by:
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Tan Hu authored
If the given type has fraction smaller than max_frac/FPROP_FRAC_BASE, the code could be modified to call __fprop_inc_percpu() directly and easier to understand. After this patch, fprop_reflect_period_percpu() will be called twice, and quicky return on pl->period == p->period test, so it would not result to significant downside of performance. Thanks for Jan's guidance. Signed-off-by:
Tan Hu <tan.hu@zte.com.cn> Signed-off-by:
Jan Kara <jack@suse.cz> Cc: <xue.zhihong@zte.com.cn> Cc: Yi Wang <wang.yi59@zte.com.cn> Cc: <wang.liang82@zte.com.cn> Link: http://lkml.kernel.org/r/1589004753-27554-1-git-send-email-tan.hu@zte.com.cnSigned-off-by:
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Joe Perches authored
Remove the trailing newline from the used-once pr_fmt and add it to the single use of pr_<level> in this code to use a more common logging style. Miscellanea: o Use %lu in the pr_debug format and remove the unnecessary cast Signed-off-by:
Joe Perches <joe@perches.com> Signed-off-by:
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Jann Horn authored
The zlib inflate code has an old micro-optimization based on the assumption that for pre-increment memory accesses, the compiler will generate code that fits better into the processor's pipeline than what would be generated for post-increment memory accesses. This optimization was already removed in upstream zlib in 2016: https://github.com/madler/zlib/commit/9aaec95e8211 This optimization causes UB according to C99, which says in section 6.5.6 "Additive operators": "If both the pointer operand and the result point to elements of the same array object, or one past the last element of the array object, the evaluation shall not produce an overflow; otherwise, the behavior is undefined". This UB is not only a theoretical concern, but can also cause trouble for future work on compiler-based sanitizers. According to the zlib commit, this optimization also is not optimal anymore with modern compilers. Replace uses of OFF, PUP and UP_UNALIGNED with their definitions in the POSTINC case, and remove the macro definitions, just like in the upstream patch. Signed-off-by:
Jann Horn <jannh@google.com> Signed-off-by:
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Jason Yan authored
Fix the following sparse warning: lib/test_lockup.c:145:14: warning: symbol 'test_inode' was not declared. Should it be static? Reported-by:
Hulk Robot <hulkci@huawei.com> Signed-off-by:
Jason Yan <yanaijie@huawei.com> Signed-off-by:
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KP Singh authored
When updating a piece of broken logic from using get_user to strncpy_from_user, we noticed that a warning which is expected when calling a function that might fault from an atomic context with pagefaults enabled disappeared. Not having this warning in place can lead to calling strncpy_from_user from an atomic context and eventually kernel crashes/stack corruption. Signed-off-by:
KP Singh <kpsingh@google.com> Signed-off-by:
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Christophe JAILLET authored
pr_xxx() functions usually have a newline at the end of the logging message. Here, this newline is added via the 'pr_fmt' macro. In order to be more consistent with other files, use a more standard convention and put these newlines back in the messages themselves and remove it from the pr_fmt macro. While at it, use __func__ instead of hardcoding a function name in the last message. Signed-off-by:
Christophe JAILLET <christophe.jaillet@wanadoo.fr> Signed-off-by:
Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20200409163234.22830-1-christophe.jaillet@wanadoo.frSigned-off-by:
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Joe Perches authored
get_maintainer behaves differently if there is a double sequential forward slash in a filename because the total number of slashes in a filename is used to match MAINTAINERS file patterns. For example: (with double slash) $ ./scripts/get_maintainer.pl -f drivers/gpu/drm//lima David Airlie <airlied@linux.ie> (maintainer:DRM DRIVERS) Daniel Vetter <daniel@ffwll.ch> (maintainer:DRM DRIVERS,commit_signer:3/42=7%) Qiang Yu <yuq825@gmail.com> (commit_signer:36/42=86%,authored:24/42=57%) Vasily Khoruzhick <anarsoul@gmail.com> (commit_signer:26/42=62%) Krzysztof Kozlowski <krzk@kernel.org> (commit_signer:5/42=12%,authored:5/42=12%) Emil Velikov <emil.velikov@collabora.com> (commit_signer:4/42=10%) dri-devel@lists.freedesktop.org (open list:DRM DRIVERS) linux-kernel@vger.kernel.org (open list) (without double slash) $ ./scripts/get_maintainer.pl -f drivers/gpu/drm/lima Qiang Yu <yuq825@gmail.com> (maintainer:DRM DRIVERS FOR LIMA) David Airlie <airlied@linux.ie> (maintainer:DRM DRIVERS) Daniel Vetter <daniel@ffwll.ch> (maintainer:DRM DRIVERS) dri-devel@lists.freedesktop.org (open list:DRM DRIVERS FOR LIMA) lima@lists.freedesktop.org (moderated list:DRM DRIVERS FOR LIMA) linux-kernel@vger.kernel.org (open list) So reduce consecutive double slashes to a single slash by using File::Spec->canonpath(). from: https://perldoc.perl.org/File/Spec/Unix.html canonpath() No physical check on the filesystem, but a logical cleanup of a path. On UNIX eliminates successive slashes and successive "/.". Reported-by:
Emil Velikov <emil.l.velikov@gmail.com> Signed-off-by:
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Joe Perches authored
.yaml files can contain maintainer/author addresses and it seems unlikely or unnecessary that individual MAINTAINER file section entries for each .yaml file will be created. So add the email addresses found in .yaml files to the default get_maintainer output. The email addresses are marked with "(in file)" when using the "--roles" or "--rolestats" options. Miscellanea: o Change $file_emails to $email_file_emails to avoid visual naming conflicts with @file_emails Signed-off-by:
Sam Ravnborg <sam@ravnborg.org> Acked-by:
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Jason Yan authored
Fix the following sparse warning: kernel/user.c:85:19: warning: symbol 'uidhash_table' was not declared. Should it be static? Reported-by:
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Alexey Dobriyan authored
"catch" is reserved keyword in C++, rename it to something both gcc and g++ accept. Rename "ign" for symmetry. Signed-off-by:
Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by:
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Andy Shevchenko authored
Instead of keeping NULL terminated array switch to use ARRAY_SIZE() which helps to further clean up. Signed-off-by:
Minchan Kim <minchan@kernel.org> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: http://lkml.kernel.org/r/20200508100758.51644-1-andriy.shevchenko@linux.intel.comSigned-off-by:
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Jason Yan authored
Fix the following coccicheck warning: include/linux/mm.h:1371:8-9: WARNING: return of 0/1 in function 'cpupid_pid_unset' with return type bool Signed-off-by:
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Zou Wei authored
Fixes coccicheck warnings: mm/zbud.c:246:1-20: WARNING: Assignment of 0/1 to bool variable mm/mremap.c:777:2-8: WARNING: Assignment of 0/1 to bool variable mm/huge_memory.c:525:9-10: WARNING: return of 0/1 in function 'is_transparent_hugepage' with return type bool Reported-by:
Zou Wei <zou_wei@huawei.com> Signed-off-by:
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Ethon Paul authored
There is a comment in typo, fix it. Signed-off-by:
Ethon Paul <ethp@qq.com> Signed-off-by:
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Ethon Paul authored
There is a typo in comment, fix it. Signed-off-by:
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Ethon Paul authored
There is a typo in comment, fix it. Signed-off-by:
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Ethon Paul authored
There is a typo in comment, fix it. Signed-off-by:
David Rientjes <rientjes@google.com> Link: http://lkml.kernel.org/r/20200411002247.14468-1-ethp@qq.comSigned-off-by:
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Ethon Paul authored
There is a typo in comment, fix it. Signed-off-by:
Ralph Campbell <rcampbell@nvidia.com> Link: http://lkml.kernel.org/r/20200411064723.15855-1-ethp@qq.comSigned-off-by:
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Ethon Paul authored
There are some typos in comment, fix them. s/responsiblity/responsibility s/oflline/offline Signed-off-by:
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Ethon Paul authored
There are some typos in comment, fix them. s/Fortunatly/Fortunately s/taked/taken s/necessory/necessary s/shink/shrink Signed-off-by:
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Ethon Paul authored
There is a typo in comment, fix it. Signed-off-by:
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Ethon Paul authored
There is a typo in comment, fix it. Signed-off-by:
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Ethon Paul authored
There is a typo in commet, fix it. Signed-off-by:
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Ethon Paul authored
There is a typo in comment, fix it. Signed-off-by:
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Ethon Paul authored
There are some typos, fix them. s/regsitration/registration s/santity/sanity s/decremeting/decrementing Signed-off-by:
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Ethon Paul authored
[akpm@linux-foundation.org: coding style fixes] Signed-off-by:
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Ethon Paul authored
There is a typo in comment, fix it. Signed-off-by:
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Ethon Paul authored
There is a typo in comment, fix it. Signed-off-by:
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Ethon Paul authored
There is a typo in comment, fix it. s/recoreded/recorded Signed-off-by:
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chenqiwu authored
The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732 ("cxgb3/l2t: Fix undefined behaviour") [akpm@linux-foundation.org: fix build] Signed-off-by:chenqiwu <chenqiwu@xiaomi.com> Signed-off-by:
Wei Yang <richard.weiyang@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: David Hildenbrand <david@redhat.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Yang Shi <yang.shi@linux.alibaba.com> Cc: Qian Cai <cai@lca.pw> Cc: Baoquan He <bhe@redhat.com> Link: http://lkml.kernel.org/r/1586599916-15456-1-git-send-email-qiwuchen55@gmail.comSigned-off-by:
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Michal Hocko authored
Memory hotlug is broken for 32b systems at least since c6f03e29 ("mm, memory_hotplug: remove zone restrictions") which has considerably reworked how can be memory associated with movable/kernel zones. The same is not really trivial to achieve in 32b where only lowmem is the kernel zone. While we can tweak this immediate problem around there are likely other land mines hidden at other places. It is also quite dubious that there is a real usecase for the memory hotplug on 32b in the first place. Low memory is just too small to be hotplugable (for hot add) and generally unusable for hotremove. Adding more memory to highmem is also dubious because it would increase the low mem or vmalloc space pressure for memmaps. Restrict the functionality to 64b systems. This will help future development to focus on usecases that have real life application. We can remove this restriction in future in presence of a real life usecase of course but until then make it explicit that hotplug on 32b is broken and requires a non trivial amount of work to fix. Robin said: "32-bit Arm doesn't support memory hotplug, and as far as I'm aware there's little likelihood of it ever wanting to. FWIW it looks like SuperH is the only pure-32-bit architecture to have hotplug support at all" Signed-off-by:
Michal Hocko <mhocko@suse.com> Signed-off-by:
David Hildenbrand <david@redhat.com> Acked-by:
Baoquan He <bhe@redhat.com> Cc: Wei Yang <richardw.yang@linux.intel.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Robin Murphy <robin.murphy@arm.com> Cc: Vamshi K Sthambamkadi <vamshi.k.sthambamkadi@gmail.com> Link: http://lkml.kernel.org/r/20200218100532.GA4151@dhcp22.suse.cz Link: https://bugzilla.kernel.org/show_bug.cgi?id=206401Signed-off-by:
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David Hildenbrand authored
Currently, when adding memory, we create entries in /sys/firmware/memmap/ as "System RAM". This will lead to kexec-tools to add that memory to the fixed-up initial memmap for a kexec kernel (loaded via kexec_load()). The memory will be considered initial System RAM by the kexec'd kernel and can no longer be reconfigured. This is not what happens during a real reboot. Let's add our memory via add_memory_driver_managed() now, so we won't create entries in /sys/firmware/memmap/ and indicate the memory as "System RAM (kmem)" in /proc/iomem. This allows everybody (especially kexec-tools) to identify that this memory is special and has to be treated differently than ordinary (hotplugged) System RAM. Before configuring the namespace: [root@localhost ~]# cat /proc/iomem ... 140000000-33fffffff : Persistent Memory 140000000-33fffffff : namespace0.0 3280000000-32ffffffff : PCI Bus 0000:00 After configuring the namespace: [root@localhost ~]# cat /proc/iomem ... 140000000-33fffffff : Persistent Memory 140000000-1481fffff : namespace0.0 148200000-33fffffff : dax0.0 3280000000-32ffffffff : PCI Bus 0000:00 After loading kmem before this change: [root@localhost ~]# cat /proc/iomem ... 140000000-33fffffff : Persistent Memory 140000000-1481fffff : namespace0.0 150000000-33fffffff : dax0.0 150000000-33fffffff : System RAM 3280000000-32ffffffff : PCI Bus 0000:00 After loading kmem after this change: [root@localhost ~]# cat /proc/iomem ... 140000000-33fffffff : Persistent Memory 140000000-1481fffff : namespace0.0 150000000-33fffffff : dax0.0 150000000-33fffffff : System RAM (kmem) 3280000000-32ffffffff : PCI Bus 0000:00 After a proper reboot: [root@localhost ~]# cat /proc/iomem ... 140000000-33fffffff : Persistent Memory 140000000-1481fffff : namespace0.0 148200000-33fffffff : dax0.0 3280000000-32ffffffff : PCI Bus 0000:00 Within the kexec kernel before this change: [root@localhost ~]# cat /proc/iomem ... 140000000-33fffffff : Persistent Memory 140000000-1481fffff : namespace0.0 150000000-33fffffff : System RAM 3280000000-32ffffffff : PCI Bus 0000:00 Within the kexec kernel after this change: [root@localhost ~]# cat /proc/iomem ... 140000000-33fffffff : Persistent Memory 140000000-1481fffff : namespace0.0 148200000-33fffffff : dax0.0 3280000000-32ffffffff : PCI Bus 0000:00 /sys/firmware/memmap/ before this change: 0000000000000000-000000000009fc00 (System RAM) 000000000009fc00-00000000000a0000 (Reserved) 00000000000f0000-0000000000100000 (Reserved) 0000000000100000-00000000bffdf000 (System RAM) 00000000bffdf000-00000000c0000000 (Reserved) 00000000feffc000-00000000ff000000 (Reserved) 00000000fffc0000-0000000100000000 (Reserved) 0000000100000000-0000000140000000 (System RAM) 0000000150000000-0000000340000000 (System RAM) /sys/firmware/memmap/ after a proper reboot: 0000000000000000-000000000009fc00 (System RAM) 000000000009fc00-00000000000a0000 (Reserved) 00000000000f0000-0000000000100000 (Reserved) 0000000000100000-00000000bffdf000 (System RAM) 00000000bffdf000-00000000c0000000 (Reserved) 00000000feffc000-00000000ff000000 (Reserved) 00000000fffc0000-0000000100000000 (Reserved) 0000000100000000-0000000140000000 (System RAM) /sys/firmware/memmap/ after this change: 0000000000000000-000000000009fc00 (System RAM) 000000000009fc00-00000000000a0000 (Reserved) 00000000000f0000-0000000000100000 (Reserved) 0000000000100000-00000000bffdf000 (System RAM) 00000000bffdf000-00000000c0000000 (Reserved) 00000000feffc000-00000000ff000000 (Reserved) 00000000fffc0000-0000000100000000 (Reserved) 0000000100000000-0000000140000000 (System RAM) kexec-tools already seem to basically ignore any System RAM that's not on top level when searching for areas to place kexec images - but also for determining crash areas to dump via kdump. Changing the resource name won't have an impact. Handle unloading of the driver after memory hotremove failed properly, by duplicating the string if necessary. Signed-off-by:
Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Baoquan He <bhe@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Dan Williams <dan.j.williams@intel.com> Link: http://lkml.kernel.org/r/20200508084217.9160-5-david@redhat.comSigned-off-by:
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David Hildenbrand authored
Memory flagged with IORESOURCE_MEM_DRIVER_MANAGED is special - it won't be part of the initial memmap of the kexec kernel and not all memory might be accessible. Don't place any kexec images onto it. Signed-off-by:
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David Hildenbrand authored
Patch series "mm/memory_hotplug: Interface to add driver-managed system ram", v4. kexec (via kexec_load()) can currently not properly handle memory added via dax/kmem, and will have similar issues with virtio-mem. kexec-tools will currently add all memory to the fixed-up initial firmware memmap. In case of dax/kmem, this means that - in contrast to a proper reboot - how that persistent memory will be used can no longer be configured by the kexec'd kernel. In case of virtio-mem it will be harmful, because that memory might contain inaccessible pieces that require coordination with hypervisor first. In both cases, we want to let the driver in the kexec'd kernel handle detecting and adding the memory, like during an ordinary reboot. Introduce add_memory_driver_managed(). More on the samentics are in patch #1. In the future, we might want to make this behavior configurable for dax/kmem- either by configuring it in the kernel (which would then also allow to configure kexec_file_load()) or in kexec-tools by also adding "System RAM (kmem)" memory from /proc/iomem to the fixed-up initial firmware memmap. More on the motivation can be found in [1] and [2]. [1] https://lkml.kernel.org/r/20200429160803.109056-1-david@redhat.com [2] https://lkml.kernel.org/r/20200430102908.10107-1-david@redhat.com This patch (of 3): Some device drivers rely on memory they managed to not get added to the initial (firmware) memmap as system RAM - so it's not used as initial system RAM by the kernel and the driver is under control. While this is the case during cold boot and after a reboot, kexec is not aware of that and might add such memory to the initial (firmware) memmap of the kexec kernel. We need ways to teach kernel and userspace that this system ram is different. For example, dax/kmem allows to decide at runtime if persistent memory is to be used as system ram. Another future user is virtio-mem, which has to coordinate with its hypervisor to deal with inaccessible parts within memory resources. We want to let users in the kernel (esp. kexec) but also user space (esp. kexec-tools) know that this memory has different semantics and needs to be handled differently: 1. Don't create entries in /sys/firmware/memmap/ 2. Name the memory resource "System RAM ($DRIVER)" (exposed via /proc/iomem) ($DRIVER might be "kmem", "virtio_mem"). 3. Flag the memory resource IORESOURCE_MEM_DRIVER_MANAGED /sys/firmware/memmap/ [1] represents the "raw firmware-provided memory map" because "on most architectures that firmware-provided memory map is modified afterwards by the kernel itself". The primary user is kexec on x86-64. Since commit d96ae530 ("memory-hotplug: create /sys/firmware/memmap entry for new memory"), we add all hotplugged memory to that firmware memmap - which makes perfect sense for traditional memory hotplug on x86-64, where real HW will also add hotplugged DIMMs to the firmware memmap. We replicate what the "raw firmware-provided memory map" looks like after hot(un)plug. To keep things simple, let the user provide the full resource name instead of only the driver name - this way, we don't have to manually allocate/craft strings for memory resources. Also use the resource name to make decisions, to avoid passing additional flags. In case the name isn't "System RAM", it's special. We don't have to worry about firmware_map_remove() on the removal path. If there is no entry, it will simply return with -EINVAL. We'll adapt dax/kmem in a follow-up patch. [1] https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-firmware-memmapSigned-off-by:
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David Hildenbrand authored
The comment in add_memory_resource() is stale: hotadd_new_pgdat() will no longer call get_pfn_range_for_nid(), as a hotadded pgdat will simply span no pages at all, until memory is moved to the zone/node via move_pfn_range_to_zone() - e.g., when onlining memory blocks. The only archs that care about memblocks for hotplugged memory (either for iterating over all system RAM or testing for memory validity) are arm64, s390x, and powerpc - due to CONFIG_ARCH_KEEP_MEMBLOCK. Without CONFIG_ARCH_KEEP_MEMBLOCK, we can simply stop messing with memblocks. Signed-off-by:
Mike Rapoport <rppt@linux.ibm.com> Acked-by:
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David Hildenbrand authored
Patch series "mm/memory_hotplug: handle memblocks only with CONFIG_ARCH_KEEP_MEMBLOCK", v1. A hotadded node/pgdat will span no pages at all, until memory is moved to the zone/node via move_pfn_range_to_zone() -> resize_pgdat_range - e.g., when onlining memory blocks. We don't have to initialize the node_start_pfn to the memory we are adding. This patch (of 2): Especially, there is an inconsistency: - Hotplugging memory to a memory-less node with cpus: node_start_pf == 0 - Offlining and removing last memory from a node: node_start_pfn == 0 - Hotplugging memory to a memory-less node without cpus: node_start_pfn != 0 As soon as memory is onlined, node_start_pfn is overwritten with the actual start. E.g., when adding two DIMMs but only onlining one of both, only that DIMM (with online memory blocks) is spanned by the node. Currently, the validity of node_start_pfn really is linked to node_spanned_pages != 0. With node_spanned_pages == 0 (e.g., before onlining memory), it has no meaning. So let's stop setting node_start_pfn, just to be overwritten via move_pfn_range_to_zone(). This avoids confusion when looking at the code, wondering which magic will be performed with the node_start_pfn in this function, when hotadding a pgdat. Signed-off-by:
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David Hildenbrand authored
Fortunately, all users of is_mem_section_removable() are gone. Get rid of it, including some now unnecessary functions. Signed-off-by:
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David Hildenbrand authored
In commit 53cdc1cb ("drivers/base/memory.c: indicate all memory blocks as removable"), the user space interface to compute whether a memory block can be offlined (exposed via /sys/devices/system/memory/memoryX/removable) has effectively been deprecated. We want to remove the leftovers of the kernel implementation. When offlining a memory block (mm/memory_hotplug.c:__offline_pages()), we'll start by: 1. Testing if it contains any holes, and reject if so 2. Testing if pages belong to different zones, and reject if so 3. Isolating the page range, checking if it contains any unmovable pages Using is_mem_section_removable() before trying to offline is not only racy, it can easily result in false positives/negatives. Let's stop manually checking is_mem_section_removable(), and let device_offline() handle it completely instead. We can remove the racy is_mem_section_removable() implementation next. We now take more locks (e.g., memory hotplug lock when offlining and the zone lock when isolating), but maybe we should optimize that implementation instead if this ever becomes a real problem (after all, memory unplug is already an expensive operation). We started using is_mem_section_removable() in commit 51925fb3 ("powerpc/pseries: Implement memory hotplug remove in the kernel"), with the initial hotremove support of lmbs. Signed-off-by:
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