kernel.git/mm/cma.c, branch linux-5.7.y

cma: don't quit at first error when activating reserved areas

2020-08-21T11:07:27Z

commit 3a5139f1c5bb76d69756fb8f13fffa173e261153 upstream. The routine cma_init_reserved_areas is designed to activate all reserved cma areas. It quits when it first encounters an error. This can leave some areas in a state where they are reserved but not activated. There is no feedback to code which performed the reservation. Attempting to allocate memory from areas in such a state will result in a BUG. Modify cma_init_reserved_areas to always attempt to activate all areas. The called routine, cma_activate_area is responsible for leaving the area in a valid state. No one is making active use of returned error codes, so change the routine to void. How to reproduce: This example uses kernelcore, hugetlb and cma as an easy way to reproduce. However, this is a more general cma issue. Two node x86 VM 16GB total, 8GB per node Kernel command line parameters, kernelcore=4G hugetlb_cma=8G Related boot time messages, hugetlb_cma: reserve 8192 MiB, up to 4096 MiB per node cma: Reserved 4096 MiB at 0x0000000100000000 hugetlb_cma: reserved 4096 MiB on node 0 cma: Reserved 4096 MiB at 0x0000000300000000 hugetlb_cma: reserved 4096 MiB on node 1 cma: CMA area hugetlb could not be activated # echo 8 > /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] SMP PTI ... Call Trace: bitmap_find_next_zero_area_off+0x51/0x90 cma_alloc+0x1a5/0x310 alloc_fresh_huge_page+0x78/0x1a0 alloc_pool_huge_page+0x6f/0xf0 set_max_huge_pages+0x10c/0x250 nr_hugepages_store_common+0x92/0x120 ? __kmalloc+0x171/0x270 kernfs_fop_write+0xc1/0x1a0 vfs_write+0xc7/0x1f0 ksys_write+0x5f/0xe0 do_syscall_64+0x4d/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fixes: c64be2bb1c6e ("drivers: add Contiguous Memory Allocator") Signed-off-by: Mike Kravetz Signed-off-by: Andrew Morton Reviewed-by: Roman Gushchin Acked-by: Barry Song Cc: Marek Szyprowski Cc: Michal Nazarewicz Cc: Kyungmin Park Cc: Joonsoo Kim Cc: Link: http://lkml.kernel.org/r/20200730163123.6451-1-mike.kravetz@oracle.com Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm/cma.c: use exact_nid true to fix possible per-numa cma leak

2020-07-09T07:39:40Z

commit 40366bd70bbbbf822ca224dfc227a8c8e868c44f upstream. Calling cma_declare_contiguous_nid() with false exact_nid for per-numa reservation can easily cause cma leak and various confusion. For example, mm/hugetlb.c is trying to reserve per-numa cma for gigantic pages. But it can easily leak cma and make users confused when system has memoryless nodes. In case the system has 4 numa nodes, and only numa node0 has memory. if we set hugetlb_cma=4G in bootargs, mm/hugetlb.c will get 4 cma areas for 4 different numa nodes. since exact_nid=false in current code, all 4 numa nodes will get cma successfully from node0, but hugetlb_cma[1 to 3] will never be available to hugepage will only allocate memory from hugetlb_cma[0]. In case the system has 4 numa nodes, both numa node0&2 has memory, other nodes have no memory. if we set hugetlb_cma=4G in bootargs, mm/hugetlb.c will get 4 cma areas for 4 different numa nodes. since exact_nid=false in current code, all 4 numa nodes will get cma successfully from node0 or 2, but hugetlb_cma[1] and [3] will never be available to hugepage as mm/hugetlb.c will only allocate memory from hugetlb_cma[0] and hugetlb_cma[2]. This causes permanent leak of the cma areas which are supposed to be used by memoryless node. Of cource we can workaround the issue by letting mm/hugetlb.c scan all cma areas in alloc_gigantic_page() even node_mask includes node0 only. that means when node_mask includes node0 only, we can get page from hugetlb_cma[1] to hugetlb_cma[3]. But this will cause kernel crash in free_gigantic_page() while it wants to free page by: cma_release(hugetlb_cma[page_to_nid(page)], page, 1 << order) On the other hand, exact_nid=false won't consider numa distance, it might be not that useful to leverage cma areas on remote nodes. I feel it is much simpler to make exact_nid true to make everything clear. After that, memoryless nodes won't be able to reserve per-numa CMA from other nodes which have memory. Fixes: cf11e85fc08c ("mm: hugetlb: optionally allocate gigantic hugepages using cma") Signed-off-by: Barry Song Signed-off-by: Andrew Morton Acked-by: Roman Gushchin Cc: Jonathan Cameron Cc: Aslan Bakirov Cc: Michal Hocko Cc: Andreas Schaufler Cc: Mike Kravetz Cc: Rik van Riel Cc: Joonsoo Kim Cc: Robin Murphy Cc: Link: http://lkml.kernel.org/r/20200628074345.27228-1-song.bao.hua@hisilicon.com Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm: cma: NUMA node interface

2020-04-10T22:36:21Z

I've noticed that there is no interface exposed by CMA which would let me to declare contigous memory on particular NUMA node. This patchset adds the ability to try to allocate contiguous memory on a specific node. It will fallback to other nodes if the specified one doesn't work. Implement a new method for declaring contigous memory on particular node and keep cma_declare_contiguous() as a wrapper. [akpm@linux-foundation.org: build fix] Signed-off-by: Aslan Bakirov Signed-off-by: Roman Gushchin Signed-off-by: Andrew Morton Acked-by: Michal Hocko Cc: Andreas Schaufler Cc: Mike Kravetz Cc: Rik van Riel Cc: Joonsoo Kim Link: http://lkml.kernel.org/r/20200407163840.92263-2-guro@fb.com Signed-off-by: Linus Torvalds

mm/cma.c: switch to bitmap_zalloc() for cma bitmap allocation

2019-12-01T20:59:09Z

kzalloc() is used for cma bitmap allocation in cma_activate_area(), switch to bitmap_zalloc() for clarity. Link: http://lkml.kernel.org/r/895d4627-f115-c77a-d454-c0a196116426@huawei.com Signed-off-by: Yunfeng Ye Reviewed-by: Andrew Morton Cc: Mike Rapoport Cc: Yue Hu Cc: Peng Fan Cc: Andrey Ryabinin Cc: Ryohei Suzuki Cc: Andrey Konovalov Cc: Doug Berger Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/cma.c: fail if fixed declaration can't be honored

2019-07-17T02:23:21Z

The description of cma_declare_contiguous() indicates that if the 'fixed' argument is true the reserved contiguous area must be exactly at the address of the 'base' argument. However, the function currently allows the 'base', 'size', and 'limit' arguments to be silently adjusted to meet alignment constraints. This commit enforces the documented behavior through explicit checks that return an error if the region does not fit within a specified region. Link: http://lkml.kernel.org/r/1561422051-16142-1-git-send-email-opendmb@gmail.com Fixes: 5ea3b1b2f8ad ("cma: add placement specifier for "cma=" kernel parameter") Signed-off-by: Doug Berger Acked-by: Michal Nazarewicz Cc: Yue Hu Cc: Mike Rapoport Cc: Laura Abbott Cc: Peng Fan Cc: Thomas Gleixner Cc: Marek Szyprowski Cc: Andrey Konovalov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/cma.c: fix a typo ("alloc_cma" -> "cma_alloc") in cma_release() comments

2019-07-17T02:23:21Z

A comment referred to a non-existent function alloc_cma(), which should have been cma_alloc(). Link: http://lkml.kernel.org/r/20190712085549.5920-1-ryh.szk.cmnty@gmail.com Signed-off-by: Ryohei Suzuki Reviewed-by: Andrew Morton Cc: Joonsoo Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 98

2019-05-24T15:37:54Z

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your optional any later version of the license extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Richard Fontana Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190520075212.713472955@linutronix.de Signed-off-by: Greg Kroah-Hartman

mm/cma.c: fix crash on CMA allocation if bitmap allocation fails

2019-05-14T16:47:47Z

f022d8cb7ec7 ("mm: cma: Don't crash on allocation if CMA area can't be activated") fixes the crash issue when activation fails via setting cma->count as 0, same logic exists if bitmap allocation fails. Link: http://lkml.kernel.org/r/20190325081309.6004-1-zbestahu@gmail.com Signed-off-by: Yue Hu Reviewed-by: Anshuman Khandual Cc: Joonsoo Kim Cc: Laura Abbott Cc: Mike Rapoport Cc: Randy Dunlap Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/cma.c: fix the bitmap status to show failed allocation reason

2019-05-14T16:47:46Z

Currently one bit in cma bitmap represents number of pages rather than one page, cma->count means cma size in pages. So to find available pages via find_next_zero_bit()/find_next_bit() we should use cma size not in pages but in bits although current free pages number is correct due to zero value of order_per_bit. Once order_per_bit is changed the bitmap status will be incorrect. The size input in cma_debug_show_areas() is not correct. It will affect the available pages at some position to debug the failure issue. This is an example with order_per_bit = 1 Before this change: [ 4.120060] cma: number of available pages: 1@93+4@108+7@121+7@137+7@153+7@169+7@185+7@201+3@213+3@221+3@229+3@237+3@245+3@253+3@261+3@269+3@277+3@285+3@293+3@301+3@309+3@317+3@325+19@333+15@369+512@512=> 638 free of 1024 total pages After this change: [ 4.143234] cma: number of available pages: 2@93+8@108+14@121+14@137+14@153+14@169+14@185+14@201+6@213+6@221+6@229+6@237+6@245+6@253+6@261+6@269+6@277+6@285+6@293+6@301+6@309+6@317+6@325+38@333+30@369=> 252 free of 1024 total pages Obviously the bitmap status before is incorrect. Link: http://lkml.kernel.org/r/20190320060829.9144-1-zbestahu@gmail.com Signed-off-by: Yue Hu Reviewed-by: Andrew Morton Cc: Joonsoo Kim Cc: Ingo Molnar Cc: Vlastimil Babka Cc: Mike Rapoport Cc: Randy Dunlap Cc: Laura Abbott Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

memblock: emphasize that memblock_alloc_range() returns a physical address

2019-03-12T17:04:01Z

Rename memblock_alloc_range() to memblock_phys_alloc_range() to emphasize that it returns a physical address. While on it, remove the 'enum memblock_flags' parameter from this function as its only user anyway sets it to MEMBLOCK_NONE, which is the default for the most of memblock allocations. Link: http://lkml.kernel.org/r/1548057848-15136-6-git-send-email-rppt@linux.ibm.com Signed-off-by: Mike Rapoport Cc: Catalin Marinas Cc: Christophe Leroy Cc: Christoph Hellwig Cc: "David S. Miller" Cc: Dennis Zhou Cc: Geert Uytterhoeven Cc: Greentime Hu Cc: Greg Kroah-Hartman Cc: Guan Xuetao Cc: Guo Ren Cc: Guo Ren [c-sky] Cc: Heiko Carstens Cc: Juergen Gross [Xen] Cc: Mark Salter Cc: Matt Turner Cc: Max Filippov Cc: Michael Ellerman Cc: Michal Simek Cc: Paul Burton Cc: Petr Mladek Cc: Richard Weinberger Cc: Rich Felker Cc: Rob Herring Cc: Rob Herring Cc: Russell King Cc: Stafford Horne Cc: Tony Luck Cc: Vineet Gupta Cc: Yoshinori Sato Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds