user/sven/linux.git/include/linux/gfp.h, branch v5.4.276

mm, vmscan: prevent infinite loop for costly GFP_NOIO | __GFP_RETRY_MAYFAIL allocations

2024-04-13T10:51:34Z

commit 803de9000f334b771afacb6ff3e78622916668b0 upstream. Sven reports an infinite loop in __alloc_pages_slowpath() for costly order __GFP_RETRY_MAYFAIL allocations that are also GFP_NOIO. Such combination can happen in a suspend/resume context where a GFP_KERNEL allocation can have __GFP_IO masked out via gfp_allowed_mask. Quoting Sven: 1. try to do a "costly" allocation (order > PAGE_ALLOC_COSTLY_ORDER) with __GFP_RETRY_MAYFAIL set. 2. page alloc's __alloc_pages_slowpath tries to get a page from the freelist. This fails because there is nothing free of that costly order. 3. page alloc tries to reclaim by calling __alloc_pages_direct_reclaim, which bails out because a zone is ready to be compacted; it pretends to have made a single page of progress. 4. page alloc tries to compact, but this always bails out early because __GFP_IO is not set (it's not passed by the snd allocator, and even if it were, we are suspending so the __GFP_IO flag would be cleared anyway). 5. page alloc believes reclaim progress was made (because of the pretense in item 3) and so it checks whether it should retry compaction. The compaction retry logic thinks it should try again, because: a) reclaim is needed because of the early bail-out in item 4 b) a zonelist is suitable for compaction 6. goto 2. indefinite stall. (end quote) The immediate root cause is confusing the COMPACT_SKIPPED returned from __alloc_pages_direct_compact() (step 4) due to lack of __GFP_IO to be indicating a lack of order-0 pages, and in step 5 evaluating that in should_compact_retry() as a reason to retry, before incrementing and limiting the number of retries. There are however other places that wrongly assume that compaction can happen while we lack __GFP_IO. To fix this, introduce gfp_compaction_allowed() to abstract the __GFP_IO evaluation and switch the open-coded test in try_to_compact_pages() to use it. Also use the new helper in: - compaction_ready(), which will make reclaim not bail out in step 3, so there's at least one attempt to actually reclaim, even if chances are small for a costly order - in_reclaim_compaction() which will make should_continue_reclaim() return false and we don't over-reclaim unnecessarily - in __alloc_pages_slowpath() to set a local variable can_compact, which is then used to avoid retrying reclaim/compaction for costly allocations (step 5) if we can't compact and also to skip the early compaction attempt that we do in some cases Link: https://lkml.kernel.org/r/20240221114357.13655-2-vbabka@suse.cz Fixes: 3250845d0526 ("Revert "mm, oom: prevent premature OOM killer invocation for high order request"") Signed-off-by: Vlastimil Babka Reported-by: Sven van Ashbrook Closes: https://lore.kernel.org/all/CAG-rBihs_xMKb3wrMO1%2B-%2Bp4fowP9oy1pa_OTkfxBzPUVOZF%2Bg@mail.gmail.com/ Tested-by: Karthikeyan Ramasubramanian Cc: Brian Geffon Cc: Curtis Malainey Cc: Jaroslav Kysela Cc: Mel Gorman Cc: Michal Hocko Cc: Takashi Iwai Cc: Signed-off-by: Andrew Morton Signed-off-by: Vlastimil Babka Signed-off-by: Greg Kroah-Hartman

arch, mm: remove stale mentions of DISCONIGMEM

2024-02-23T07:25:13Z

[ Upstream commit d3c251ab95b69f3dc189c4657baeac1b4c050789 ] There are several places that mention DISCONIGMEM in comments or have stale code guarded by CONFIG_DISCONTIGMEM. Remove the dead code and update the comments. Link: https://lkml.kernel.org/r/20210608091316.3622-7-rppt@kernel.org Signed-off-by: Mike Rapoport Acked-by: Arnd Bergmann Reviewed-by: David Hildenbrand Cc: Geert Uytterhoeven Cc: Ivan Kokshaysky Cc: Jonathan Corbet Cc: Matt Turner Cc: Richard Henderson Cc: Vineet Gupta Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Stable-dep-of: e1a9ae457369 ("mips: Fix max_mapnr being uninitialized on early stages") Signed-off-by: Sasha Levin

net: fix sk_page_frag() recursion from memory reclaim

2019-10-28T23:17:31Z

sk_page_frag() optimizes skb_frag allocations by using per-task skb_frag cache when it knows it's the only user. The condition is determined by seeing whether the socket allocation mask allows blocking - if the allocation may block, it obviously owns the task's context and ergo exclusively owns current->task_frag. Unfortunately, this misses recursion through memory reclaim path. Please take a look at the following backtrace. [2] RIP: 0010:tcp_sendmsg_locked+0xccf/0xe10 ... tcp_sendmsg+0x27/0x40 sock_sendmsg+0x30/0x40 sock_xmit.isra.24+0xa1/0x170 [nbd] nbd_send_cmd+0x1d2/0x690 [nbd] nbd_queue_rq+0x1b5/0x3b0 [nbd] __blk_mq_try_issue_directly+0x108/0x1b0 blk_mq_request_issue_directly+0xbd/0xe0 blk_mq_try_issue_list_directly+0x41/0xb0 blk_mq_sched_insert_requests+0xa2/0xe0 blk_mq_flush_plug_list+0x205/0x2a0 blk_flush_plug_list+0xc3/0xf0 [1] blk_finish_plug+0x21/0x2e _xfs_buf_ioapply+0x313/0x460 __xfs_buf_submit+0x67/0x220 xfs_buf_read_map+0x113/0x1a0 xfs_trans_read_buf_map+0xbf/0x330 xfs_btree_read_buf_block.constprop.42+0x95/0xd0 xfs_btree_lookup_get_block+0x95/0x170 xfs_btree_lookup+0xcc/0x470 xfs_bmap_del_extent_real+0x254/0x9a0 __xfs_bunmapi+0x45c/0xab0 xfs_bunmapi+0x15/0x30 xfs_itruncate_extents_flags+0xca/0x250 xfs_free_eofblocks+0x181/0x1e0 xfs_fs_destroy_inode+0xa8/0x1b0 destroy_inode+0x38/0x70 dispose_list+0x35/0x50 prune_icache_sb+0x52/0x70 super_cache_scan+0x120/0x1a0 do_shrink_slab+0x120/0x290 shrink_slab+0x216/0x2b0 shrink_node+0x1b6/0x4a0 do_try_to_free_pages+0xc6/0x370 try_to_free_mem_cgroup_pages+0xe3/0x1e0 try_charge+0x29e/0x790 mem_cgroup_charge_skmem+0x6a/0x100 __sk_mem_raise_allocated+0x18e/0x390 __sk_mem_schedule+0x2a/0x40 [0] tcp_sendmsg_locked+0x8eb/0xe10 tcp_sendmsg+0x27/0x40 sock_sendmsg+0x30/0x40 ___sys_sendmsg+0x26d/0x2b0 __sys_sendmsg+0x57/0xa0 do_syscall_64+0x42/0x100 entry_SYSCALL_64_after_hwframe+0x44/0xa9 In [0], tcp_send_msg_locked() was using current->page_frag when it called sk_wmem_schedule(). It already calculated how many bytes can be fit into current->page_frag. Due to memory pressure, sk_wmem_schedule() called into memory reclaim path which called into xfs and then IO issue path. Because the filesystem in question is backed by nbd, the control goes back into the tcp layer - back into tcp_sendmsg_locked(). nbd sets sk_allocation to (GFP_NOIO | __GFP_MEMALLOC) which makes sense - it's in the process of freeing memory and wants to be able to, e.g., drop clean pages to make forward progress. However, this confused sk_page_frag() called from [2]. Because it only tests whether the allocation allows blocking which it does, it now thinks current->page_frag can be used again although it already was being used in [0]. After [2] used current->page_frag, the offset would be increased by the used amount. When the control returns to [0], current->page_frag's offset is increased and the previously calculated number of bytes now may overrun the end of allocated memory leading to silent memory corruptions. Fix it by adding gfpflags_normal_context() which tests sleepable && !reclaim and use it to determine whether to use current->task_frag. v2: Eric didn't like gfp flags being tested twice. Introduce a new helper gfpflags_normal_context() and combine the two tests. Signed-off-by: Tejun Heo Cc: Josef Bacik Cc: Eric Dumazet Cc: stable@vger.kernel.org Signed-off-by: David S. Miller

Revert "Revert "Revert "mm, thp: consolidate THP gfp handling into alloc_hugepage_direct_gfpmask""

2019-09-28T21:05:38Z

This reverts commit 92717d429b38e4f9f934eed7e605cc42858f1839. Since commit a8282608c88e ("Revert "mm, thp: restore node-local hugepage allocations"") is reverted in this series, it is better to restore the previous 5.2 behavior between the thp allocation and the page allocator rather than to attempt any consolidation or cleanup for a policy that is now reverted. It's less risky during an rc cycle and subsequent patches in this series further modify the same policy that the pre-5.3 behavior implements. Consolidation and cleanup can be done subsequent to a sane default page allocation strategy, so this patch reverts a cleanup done on a strategy that is now reverted and thus is the least risky option. Signed-off-by: David Rientjes Cc: Andrea Arcangeli Cc: Michal Hocko Cc: Mel Gorman Cc: Vlastimil Babka Cc: Stefan Priebe - Profihost AG Cc: "Kirill A. Shutemov" Cc: Andrew Morton Signed-off-by: Linus Torvalds

Revert "Revert "mm, thp: consolidate THP gfp handling into alloc_hugepage_direct_gfpmask""

2019-08-13T23:06:52Z

Patch series "reapply: relax __GFP_THISNODE for MADV_HUGEPAGE mappings". The fixes for what was originally reported as "pathological THP behavior" we rightfully reverted to be sure not to introduced regressions at end of a merge window after a severe regression report from the kernel bot. We can safely re-apply them now that we had time to analyze the problem. The mm process worked fine, because the good fixes were eventually committed upstream without excessive delay. The regression reported by the kernel bot however forced us to revert the good fixes to be sure not to introduce regressions and to give us the time to analyze the issue further. The silver lining is that this extra time allowed to think more at this issue and also plan for a future direction to improve things further in terms of THP NUMA locality. This patch (of 2): This reverts commit 356ff8a9a78fb35d ("Revert "mm, thp: consolidate THP gfp handling into alloc_hugepage_direct_gfpmask"). So it reapplies 89c83fb539f954 ("mm, thp: consolidate THP gfp handling into alloc_hugepage_direct_gfpmask"). Consolidation of the THP allocation flags at the same place was meant to be a clean up to easier handle otherwise scattered code which is imposing a maintenance burden. There were no real problems observed with the gfp mask consolidation but the reversion was rushed through without a larger consensus regardless. This patch brings the consolidation back because this should make the long term maintainability easier as well as it should allow future changes to be less error prone. [mhocko@kernel.org: changelog additions] Link: http://lkml.kernel.org/r/20190503223146.2312-2-aarcange@redhat.com Signed-off-by: Andrea Arcangeli Acked-by: Michal Hocko Cc: Mel Gorman Cc: Vlastimil Babka Cc: David Rientjes Cc: Zi Yan Cc: Stefan Priebe - Profihost AG Cc: "Kirill A. Shutemov" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

hugetlb: allow to free gigantic pages regardless of the configuration

2019-05-14T16:47:47Z

On systems without CONTIG_ALLOC activated but that support gigantic pages, boottime reserved gigantic pages can not be freed at all. This patch simply enables the possibility to hand back those pages to memory allocator. Link: http://lkml.kernel.org/r/20190327063626.18421-5-alex@ghiti.fr Signed-off-by: Alexandre Ghiti Acked-by: David S. Miller [sparc] Reviewed-by: Mike Kravetz Cc: Andy Lutomirsky Cc: Aneesh Kumar K.V Cc: Benjamin Herrenschmidt Cc: Borislav Petkov Cc: Catalin Marinas Cc: Dave Hansen Cc: Heiko Carstens Cc: "H . Peter Anvin" Cc: Ingo Molnar Cc: Martin Schwidefsky Cc: Michael Ellerman Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Rich Felker Cc: Thomas Gleixner Cc: Vlastimil Babka Cc: Will Deacon Cc: Yoshinori Sato Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: simplify MEMORY_ISOLATION && COMPACTION || CMA into CONTIG_ALLOC

2019-05-14T16:47:47Z

This condition allows to define alloc_contig_range, so simplify it into a more accurate naming. Link: http://lkml.kernel.org/r/20190327063626.18421-4-alex@ghiti.fr Signed-off-by: Alexandre Ghiti Suggested-by: Vlastimil Babka Acked-by: Vlastimil Babka Cc: Andy Lutomirsky Cc: Aneesh Kumar K.V Cc: Benjamin Herrenschmidt Cc: Borislav Petkov Cc: Catalin Marinas Cc: Dave Hansen Cc: David S. Miller Cc: Heiko Carstens Cc: "H . Peter Anvin" Cc: Ingo Molnar Cc: Martin Schwidefsky Cc: Michael Ellerman Cc: Mike Kravetz Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Rich Felker Cc: Thomas Gleixner Cc: Will Deacon Cc: Yoshinori Sato Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: shuffle GFP_* flags

2019-03-06T05:07:16Z

GFP_KERNEL is one of the most used constant but on archs like arm with fixed length instruction some constants are more equal than the others. Constants with tightly packed bits can be injected directly into instruction stream: 0: e3a00d33 mov r0, #3264 ; 0xcc0 Others require multiple instructions or even loading out of instruction stream: 0: e3a000c0 mov r0, #192 ; 0xc0 4: e3400060 movt r0, #96 ; 0x60 Shuffle GFP_* flags so that GFP_KERNEL/GFP_ATOMIC + __GFP_ZERO bits are close to each other. Savings on arm configs are ~0.1%. Link: http://lkml.kernel.org/r/20190109201838.GA9140@avx2 Signed-off-by: Alexey Dobriyan Reviewed-by: Andrew Morton Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

include/linux/gfp.h: fix typo

2018-12-28T20:11:52Z

Fix misspelled "satisfied" Link: http://lkml.kernel.org/r/20181227232354.64562-1-ksspiers@google.com Signed-off-by: Kyle Spiers Reviewed-by: Andrew Morton Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Revert "mm, thp: consolidate THP gfp handling into alloc_hugepage_direct_gfpmask"

2018-12-08T18:26:20Z

This reverts commit 89c83fb539f95491be80cdd5158e6f0ce329e317. This should have been done as part of 2f0799a0ffc0 ("mm, thp: restore node-local hugepage allocations"). The movement of the thp allocation policy from alloc_pages_vma() to alloc_hugepage_direct_gfpmask() was intended to only set __GFP_THISNODE for mempolicies that are not MPOL_BIND whereas the revert could set this regardless of mempolicy. While the check for MPOL_BIND between alloc_hugepage_direct_gfpmask() and alloc_pages_vma() was racy, that has since been removed since the revert. What is left is the possibility to use __GFP_THISNODE in policy_node() when it is unexpected because the special handling for hugepages in alloc_pages_vma() was removed as part of the consolidation. Secondly, prior to 89c83fb539f9, alloc_pages_vma() implemented a somewhat different policy for hugepage allocations, which were allocated through alloc_hugepage_vma(). For hugepage allocations, if the allocating process's node is in the set of allowed nodes, allocate with __GFP_THISNODE for that node (for MPOL_PREFERRED, use that node with __GFP_THISNODE instead). This was changed for shmem_alloc_hugepage() to allow fallback to other nodes in 89c83fb539f9 as it did for new_page() in mm/mempolicy.c which is functionally different behavior and removes the requirement to only allocate hugepages locally. So this commit does a full revert of 89c83fb539f9 instead of the partial revert that was done in 2f0799a0ffc0. The result is the same thp allocation policy for 4.20 that was in 4.19. Fixes: 89c83fb539f9 ("mm, thp: consolidate THP gfp handling into alloc_hugepage_direct_gfpmask") Fixes: 2f0799a0ffc0 ("mm, thp: restore node-local hugepage allocations") Signed-off-by: David Rientjes Acked-by: Vlastimil Babka Cc: Andrea Arcangeli Cc: Mel Gorman Cc: Michal Hocko Cc: Andrew Morton Signed-off-by: Linus Torvalds