343ab8178f
In case of simultaneous vmalloc allocations, for example it is 1GB and 12 CPUs my system is able to hit "BUG: soft lockup" for !CONFIG_PREEMPT kernel. RIP: 0010:__alloc_pages_bulk+0xa9f/0xbb0 Call Trace: __vmalloc_node_range+0x11c/0x2d0 __vmalloc_node+0x4b/0x70 fix_size_alloc_test+0x44/0x60 [test_vmalloc] test_func+0xe7/0x1f0 [test_vmalloc] kthread+0x11a/0x140 ret_from_fork+0x22/0x30 To address this issue invoke a bulk-allocator many times until all pages are obtained, i.e. do batched page requests adding cond_resched() meanwhile to reschedule. Batched value is hard-coded and is 100 pages per call. Link: https://lkml.kernel.org/r/20210707182639.31282-1-urezki@gmail.com Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Hillf Danton <hdanton@sina.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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.