- 25 Feb, 2021 1 commit
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Linus Torvalds authored
Merge misc updates from Andrew Morton: "A few small subsystems and some of MM. 172 patches. Subsystems affected by this patch series: hexagon, scripts, ntfs, ocfs2, vfs, and mm (slab-generic, slab, slub, debug, pagecache, swap, memcg, pagemap, mprotect, mremap, page-reporting, vmalloc, kasan, pagealloc, memory-failure, hugetlb, vmscan, z3fold, compaction, mempolicy, oom-kill, hugetlbfs, and migration)" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (172 commits) mm/migrate: remove unneeded semicolons hugetlbfs: remove unneeded return value of hugetlb_vmtruncate() hugetlbfs: fix some comment typos hugetlbfs: correct some obsolete comments about inode i_mutex hugetlbfs: make hugepage size conversion more readable hugetlbfs: remove meaningless variable avoid_reserve hugetlbfs: correct obsolete function name in hugetlbfs_read_iter() hugetlbfs: use helper macro default_hstate in init_hugetlbfs_fs hugetlbfs: remove useless BUG_ON(!inode) in hugetlbfs_setattr() hugetlbfs: remove special hugetlbfs_set_page_dirty() mm/hugetlb: change hugetlb_reserve_pages() to type bool mm, oom: fix a comment in dump_task() mm/mempolicy: use helper range_in_vma() in queue_pages_test_walk() numa balancing: migrate on fault among multiple bound nodes mm, compaction: make fast_isolate_freepages() stay within zone mm/compaction: fix misbehaviors of fast_find_migrateblock() mm/compaction: correct deferral logic for proactive compaction mm/compaction: remove duplicated VM_BUG_ON_PAGE !PageLocked mm/compaction: remove rcu_read_lock during page compaction z3fold: simplify the zhdr initialization code in init_z3fold_page() ...
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- 24 Feb, 2021 39 commits
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Chengyang Fan authored
Remove superfluous semicolons after function definitions. Link: https://lkml.kernel.org/r/20210115110131.2359683-1-cy.fan@huawei.comSigned-off-by:
Chengyang Fan <cy.fan@huawei.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Miaohe Lin authored
The function hugetlb_vmtruncate() is guaranteed to always success since commit 7aa91e10 ("hugetlb: allow extending ftruncate on hugetlbfs"). So we should remove the unneeded return value which is always 0. Link: https://lkml.kernel.org/r/20210208084637.47789-1-linmiaohe@huawei.comSigned-off-by:
Miaohe Lin <linmiaohe@huawei.com> Reviewed-by:
Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by:
David Hildenbrand <david@redhat.com> Signed-off-by:
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Miaohe Lin authored
Fix typos reserv to reserve, minimim to minimum. No functional change intended. Link: https://lkml.kernel.org/r/20210130092351.28072-1-linmiaohe@huawei.comSigned-off-by:
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Miaohe Lin authored
Since commit 9902af79 ("parallel lookups: actual switch to rwsem"), i_mutex of inode is converted to i_rwsem. So replace i_mutex with i_rwsem to make comments up to date. Link: https://lkml.kernel.org/r/20210127093111.36672-1-linmiaohe@huawei.comSigned-off-by:
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Miaohe Lin authored
The calculation 1U << (h->order + PAGE_SHIFT - 10) is actually equal to (PAGE_SHIFT << (h->order)) >> 10. So we can make it more readable by replace it with huge_page_size(h) >> 10. Link: https://lkml.kernel.org/r/20210122083141.24548-1-linmiaohe@huawei.comSigned-off-by:
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Miaohe Lin authored
The variable avoid_reserve is meaningless because we never changed its value and just passed it to alloc_huge_page(). So remove it to make code more clear that in hugetlbfs_fallocate, we never avoid reserve when alloc hugepage yet. Also add a comment offered by Mike Kravetz to explain this. Link: https://lkml.kernel.org/r/20210120071508.9078-1-linmiaohe@huawei.comSigned-off-by:
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Miaohe Lin authored
Since commit 36e78914 ("kill do_generic_mapping_read"), the function do_generic_mapping_read() is renamed to do_generic_file_read(). And then commit 47c27bc4 ("fs: pass iocb to do_generic_file_read") renamed it to generic_file_buffered_read(). So replace do_generic_mapping_read() with generic_file_buffered_read() to keep comment uptodate. Link: https://lkml.kernel.org/r/20210118063210.47118-1-linmiaohe@huawei.comSigned-off-by:
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Miaohe Lin authored
Since commit e5ff2159 ("hugetlb: multiple hstates for multiple page sizes"), we can use macro default_hstate to get the struct hstate which we use by default. But init_hugetlbfs_fs() forgot to use it. Link: https://lkml.kernel.org/r/20210116091827.20982-1-linmiaohe@huawei.comSigned-off-by:
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Miaohe Lin authored
When we reach here with inode = NULL, we should have crashed as inode has already been dereferenced via hstate_inode. So this BUG_ON(!inode) does not take effect and should be removed. Link: https://lkml.kernel.org/r/20210118110700.52506-1-linmiaohe@huawei.comSigned-off-by:
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Mike Kravetz authored
Matthew Wilcox noticed that hugetlbfs_set_page_dirty always returns 0. Instead, it should return 1 or 0 depending on the previous state of the dirty bit. In addition, the call to compound_head is redundant as it is also performed in calling routine set_page_dirty. Replace the hugetlbfs specific routine hugetlbfs_set_page_dirty with __set_page_dirty_no_writeback as it addresses both of these issues. Link: https://lkml.kernel.org/r/20201221192542.15732-2-mike.kravetz@oracle.comSigned-off-by:
Matthew Wilcox <willy@infradead.org> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: David Hildenbrand <david@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by:
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Mike Kravetz authored
While reviewing a bug in hugetlb_reserve_pages, it was noticed that all callers ignore the return value. Any failure is considered an ENOMEM error by the callers. Change the function to be of type bool. The function will return true if the reservation was successful, false otherwise. Callers currently assume a zero return code indicates success. Change the callers to look for true to indicate success. No functional change, only code cleanup. Link: https://lkml.kernel.org/r/20201221192542.15732-1-mike.kravetz@oracle.comSigned-off-by:
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Tang Yizhou authored
If p is a kthread, it will be checked in oom_unkillable_task() so we can delete the corresponding comment. Link: https://lkml.kernel.org/r/20210125133006.7242-1-tangyizhou@huawei.comSigned-off-by:
Tang Yizhou <tangyizhou@huawei.com> Acked-by:
David Rientjes <rientjes@google.com> Acked-by:
Michal Hocko <mhocko@suse.com> Signed-off-by:
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Miaohe Lin authored
The helper range_in_vma() is introduced via commit 017b1660 ("mm: migration: fix migration of huge PMD shared pages"). But we forgot to use it in queue_pages_test_walk(). Link: https://lkml.kernel.org/r/20210130091352.20220-1-linmiaohe@huawei.comSigned-off-by:
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Huang Ying authored
Now, NUMA balancing can only optimize the page placement among the NUMA nodes if the default memory policy is used. Because the memory policy specified explicitly should take precedence. But this seems too strict in some situations. For example, on a system with 4 NUMA nodes, if the memory of an application is bound to the node 0 and 1, NUMA balancing can potentially migrate the pages between the node 0 and 1 to reduce cross-node accessing without breaking the explicit memory binding policy. So in this patch, we add MPOL_F_NUMA_BALANCING mode flag to set_mempolicy() when mode is MPOL_BIND. With the flag specified, NUMA balancing will be enabled within the thread to optimize the page placement within the constrains of the specified memory binding policy. With the newly added flag, the NUMA balancing control mechanism becomes, - sysctl knob numa_balancing can enable/disable the NUMA balancing globally. - even if sysctl numa_balancing is enabled, the NUMA balancing will be disabled for the memory areas or applications with the explicit memory policy by default. - MPOL_F_NUMA_BALANCING can be used to enable the NUMA balancing for the applications when specifying the explicit memory policy (MPOL_BIND). Various page placement optimization based on the NUMA balancing can be done with these flags. As the first step, in this patch, if the memory of the application is bound to multiple nodes (MPOL_BIND), and in the hint page fault handler the accessing node are in the policy nodemask, the page will be tried to be migrated to the accessing node to reduce the cross-node accessing. If the newly added MPOL_F_NUMA_BALANCING flag is specified by an application on an old kernel version without its support, set_mempolicy() will return -1 and errno will be set to EINVAL. The application can use this behavior to run on both old and new kernel versions. And if the MPOL_F_NUMA_BALANCING flag is specified for the mode other than MPOL_BIND, set_mempolicy() will return -1 and errno will be set to EINVAL as before. Because we don't support optimization based on the NUMA balancing for these modes. In the previous version of the patch, we tried to reuse MPOL_MF_LAZY for mbind(). But that flag is tied to MPOL_MF_MOVE.*, so it seems not a good API/ABI for the purpose of the patch. And because it's not clear whether it's necessary to enable NUMA balancing for a specific memory area inside an application, so we only add the flag at the thread level (set_mempolicy()) instead of the memory area level (mbind()). We can do that when it become necessary. To test the patch, we run a test case as follows on a 4-node machine with 192 GB memory (48 GB per node). 1. Change pmbench memory accessing benchmark to call set_mempolicy() to bind its memory to node 1 and 3 and enable NUMA balancing. Some related code snippets are as follows, #include <numaif.h> #include <numa.h> struct bitmask *bmp; int ret; bmp = numa_parse_nodestring("1,3"); ret = set_mempolicy(MPOL_BIND | MPOL_F_NUMA_BALANCING, bmp->maskp, bmp->size + 1); /* If MPOL_F_NUMA_BALANCING isn't supported, fall back to MPOL_BIND */ if (ret < 0 && errno == EINVAL) ret = set_mempolicy(MPOL_BIND, bmp->maskp, bmp->size + 1); if (ret < 0) { perror("Failed to call set_mempolicy"); exit(-1); } 2. Run a memory eater on node 3 to use 40 GB memory before running pmbench. 3. Run pmbench with 64 processes, the working-set size of each process is 640 MB, so the total working-set size is 64 * 640 MB = 40 GB. The CPU and the memory (as in step 1.) of all pmbench processes is bound to node 1 and 3. So, after CPU usage is balanced, some pmbench processes run on the CPUs of the node 3 will access the memory of the node 1. 4. After the pmbench processes run for 100 seconds, kill the memory eater. Now it's possible for some pmbench processes to migrate their pages from node 1 to node 3 to reduce cross-node accessing. Test results show that, with the patch, the pages can be migrated from node 1 to node 3 after killing the memory eater, and the pmbench score can increase about 17.5%. Link: https://lkml.kernel.org/r/20210120061235.148637-2-ying.huang@intel.comSigned-off-by:"Huang, Ying" <ying.huang@intel.com> Acked-by:
Mel Gorman <mgorman@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Rik van Riel <riel@surriel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by:
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Vlastimil Babka authored
Compaction always operates on pages from a single given zone when isolating both pages to migrate and freepages. Pageblock boundaries are intersected with zone boundaries to be safe in case zone starts or ends in the middle of pageblock. The use of pageblock_pfn_to_page() protects against non-contiguous pageblocks. The functions fast_isolate_freepages() and fast_isolate_around() don't currently protect the fast freepage isolation thoroughly enough against these corner cases, and can result in freepage isolation operate outside of zone boundaries: - in fast_isolate_freepages() if we get a pfn from the first pageblock of a zone that starts in the middle of that pageblock, 'highest' can be a pfn outside of the zone. If we fail to isolate anything in this function, we may then call fast_isolate_around() on a pfn outside of the zone and there effectively do a set_pageblock_skip(page_to_pfn(highest)) which may currently hit a VM_BUG_ON() in some configurations - fast_isolate_around() checks only the zone end boundary and not beginning, nor that the pageblock is contiguous (with pageblock_pfn_to_page()) so it's possible that we end up calling isolate_freepages_block() on a range of pfn's from two different zones and end up e.g. isolating freepages under the wrong zone's lock. This patch should fix the above issues. Link: https://lkml.kernel.org/r/20210217173300.6394-1-vbabka@suse.cz Fixes: 5a811889 ("mm, compaction: use free lists to quickly locate a migration target") Signed-off-by:
Vlastimil Babka <vbabka@suse.cz> Acked-by:
Mel Gorman <mgorman@techsingularity.net> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Hildenbrand <david@redhat.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by:
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Wonhyuk Yang authored
In the fast_find_migrateblock(), it iterates ocer the freelist to find the proper pageblock. But there are some misbehaviors. First, if the page we found is equal to cc->migrate_pfn, it is considered that we didn't find a suitable pageblock. Secondly, if the loop was terminated because order is less than PAGE_ALLOC_COSTLY_ORDER, it could be considered that we found a suitable one. Thirdly, if the skip bit is set on the page block and we goto continue, it doesn't check nr_scanned. Fourthly, if the page block's skip bit is set, it checks that page block is the last of list, which is unnecessary. Link: https://lkml.kernel.org/r/20210128130411.6125-1-vvghjk1234@gmail.com Fixes: 70b44595 ("mm, compaction: use free lists to quickly locate a migration source") Signed-off-by:
Wonhyuk Yang <vvghjk1234@gmail.com> Acked-by:
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Charan Teja Reddy authored
should_proactive_compact_node() returns true when sum of the weighted fragmentation score of all the zones in the node is greater than the wmark_high of compaction, which then triggers the proactive compaction that operates on the individual zones of the node. But proactive compaction runs on the zone only when its weighted fragmentation score is greater than wmark_low(=wmark_high - 10). This means that the sum of the weighted fragmentation scores of all the zones can exceed the wmark_high but individual weighted fragmentation zone scores can still be less than wmark_low which makes the unnecessary trigger of the proactive compaction only to return doing nothing. Issue with the return of proactive compaction with out even trying is its deferral. It is simply deferred for 1 << COMPACT_MAX_DEFER_SHIFT if the scores across the proactive compaction is same, thinking that compaction didn't make any progress but in reality it didn't even try. With the delay between successive retries for proactive compaction is 500msec, it can result into the deferral for ~30sec with out even trying the proactive compaction. Test scenario is that: compaction_proactiveness=50 thus the wmark_low = 50 and wmark_high = 60. System have 2 zones(Normal and Movable) with sizes 5GB and 6GB respectively. After opening some apps on the android, the weighted fragmentation scores of these zones are 47 and 49 respectively. Since the sum of these fragmentation scores are above the wmark_high which triggers the proactive compaction and there since the individual zones weighted fragmentation scores are below wmark_low, it returns without trying the proactive compaction. As a result the weighted fragmentation scores of the zones are still 47 and 49 which makes the existing logic to defer the compaction thinking that noprogress is made across the compaction. Fix this by checking just zone fragmentation score, not the weighted, in __compact_finished() and use the zones weighted fragmentation score in fragmentation_score_node(). In the test case above, If the weighted average of is above wmark_high, then individual score (not adjusted) of atleast one zone has to be above wmark_high. Thus it avoids the unnecessary trigger and deferrals of the proactive compaction. Link: https://lkml.kernel.org/r/1610989938-31374-1-git-send-email-charante@codeaurora.orgSigned-off-by:
Charan Teja Reddy <charante@codeaurora.org> Suggested-by:
Khalid Aziz <khalid.aziz@oracle.com> Acked-by:
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Miaohe Lin authored
The VM_BUG_ON_PAGE(!PageLocked(page), page) is also done in PageMovable. Remove this explicitly one. Link: https://lkml.kernel.org/r/20210109081420.46030-1-linmiaohe@huawei.comSigned-off-by:
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Alex Shi authored
isolate_migratepages_block() used rcu_read_lock() with the intention of safeguarding against the mem_cgroup being destroyed concurrently; but its TestClearPageLRU already protects against that. Delete the unnecessary rcu_read_lock() and _unlock(). Hugh Dickins helped on commit log polishing, Thanks! Link: https://lkml.kernel.org/r/1608614453-10739-3-git-send-email-alex.shi@linux.alibaba.comSigned-off-by:
Alex Shi <alex.shi@linux.alibaba.com> Acked-by:
Hugh Dickins <hughd@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by:
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Miaohe Lin authored
We can simplify the zhdr initialization by memset() the zhdr first instead of set struct member to zero one by one. This would also make code more compact and clear. Link: https://lkml.kernel.org/r/20210120085851.16159-1-linmiaohe@huawei.comSigned-off-by:
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Miaohe Lin authored
Since commit dcf5aedb ("z3fold: stricter locking and more careful reclaim"), release_z3fold_page() is used again. So we can drop the unused attribute safely. Link: https://lkml.kernel.org/r/20210120084008.58432-1-linmiaohe@huawei.comSigned-off-by:
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Dave Hansen authored
I went to go add a new RECLAIM_* mode for the zone_reclaim_mode sysctl. Like a good kernel developer, I also went to go update the documentation. I noticed that the bits in the documentation didn't match the bits in the #defines. The VM never explicitly checks the RECLAIM_ZONE bit. The bit is, however implicitly checked when checking 'node_reclaim_mode==0'. The RECLAIM_ZONE #define was removed in a cleanup. That, by itself is fine. But, when the bit was removed (bit 0) the _other_ bit locations also got changed. That's not OK because the bit values are documented to mean one specific thing. Users surely do not expect the meaning to change from kernel to kernel. The end result is that if someone had a script that did: sysctl vm.zone_reclaim_mode=1 it would have gone from enabling node reclaim for clean unmapped pages to writing out pages during node reclaim after the commit in question. That's not great. Put the bits back the way they were and add a comment so something like this is a bit harder to do again. Update the documentation to make it clear that the first bit is ignored. Link: https://lkml.kernel.org/r/20210219172555.FF0CDF23@viggo.jf.intel.comSigned-off-by:
Dave Hansen <dave.hansen@linux.intel.com> Fixes: 648b5cf3 ("mm/vmscan: remove unused RECLAIM_OFF/RECLAIM_ZONE") Reviewed-by:
Ben Widawsky <ben.widawsky@intel.com> Reviewed-by:
Oscar Salvador <osalvador@suse.de> Acked-by:
Christoph Lameter <cl@linux.com> Cc: Alex Shi <alex.shi@linux.alibaba.com> Cc: Daniel Wagner <dwagner@suse.de> Cc: "Tobin C. Harding" <tobin@kernel.org> Cc: Christoph Lameter <cl@linux.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Huang Ying <ying.huang@intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Qian Cai <cai@lca.pw> Cc: <stable@vger.kernel.org> Signed-off-by:
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Mike Kravetz authored
Gerald Schaefer reported a panic on s390 in hugepage_subpool_put_pages() with linux-next 5.12.0-20210222. Call trace: hugepage_subpool_put_pages.part.0+0x2c/0x138 __free_huge_page+0xce/0x310 alloc_pool_huge_page+0x102/0x120 set_max_huge_pages+0x13e/0x350 hugetlb_sysctl_handler_common+0xd8/0x110 hugetlb_sysctl_handler+0x48/0x58 proc_sys_call_handler+0x138/0x238 new_sync_write+0x10e/0x198 vfs_write.part.0+0x12c/0x238 ksys_write+0x68/0xf8 do_syscall+0x82/0xd0 __do_syscall+0xb4/0xc8 system_call+0x72/0x98 This is a result of the change which moved the hugetlb page subpool pointer from page->private to page[1]->private. When new pages are allocated from the buddy allocator, the private field of the head page will be cleared, but the private field of subpages is not modified. Therefore, old values may remain. Fix by initializing hugetlb page subpool pointer in prep_new_huge_page(). Link: https://lkml.kernel.org/r/20210223215544.313871-1-mike.kravetz@oracle.com Fixes: f1280272ae4d ("hugetlb: use page.private for hugetlb specific page flags") Signed-off-by:
Gerald Schaefer <gerald.schaefer@linux.ibm.com> Reviewed-by:
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Mike Kravetz authored
Add comments, no functional change. Link: https://lkml.kernel.org/r/62a80585-2a73-10cc-4a2d-5721540d4ad2@oracle.comSigned-off-by:
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Mike Kravetz authored
Use new hugetlb specific HPageFreed flag to replace the PageHugeFreed interfaces. Link: https://lkml.kernel.org/r/20210122195231.324857-6-mike.kravetz@oracle.comSigned-off-by:
Muchun Song <songmuchun@bytedance.com> Acked-by:
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Mike Kravetz authored
Use new hugetlb specific HPageTemporary flag to replace the PageHugeTemporary() interfaces. PageHugeTemporary does contain a PageHuge() check. However, this interface is only used within hugetlb code where we know we are dealing with a hugetlb page. Therefore, the check can be eliminated. Link: https://lkml.kernel.org/r/20210122195231.324857-5-mike.kravetz@oracle.comSigned-off-by:
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Mike Kravetz authored
Use the new hugetlb page specific flag HPageMigratable to replace the page_huge_active interfaces. By it's name, page_huge_active implied that a huge page was on the active list. However, that is not really what code checking the flag wanted to know. It really wanted to determine if the huge page could be migrated. This happens when the page is actually added to the page cache and/or task page table. This is the reasoning behind the name change. The VM_BUG_ON_PAGE() calls in the *_huge_active() interfaces are not really necessary as we KNOW the page is a hugetlb page. Therefore, they are removed. The routine page_huge_active checked for PageHeadHuge before testing the active bit. This is unnecessary in the case where we hold a reference or lock and know it is a hugetlb head page. page_huge_active is also called without holding a reference or lock (scan_movable_pages), and can race with code freeing the page. The extra check in page_huge_active shortened the race window, but did not prevent the race. Offline code calling scan_movable_pages already deals with these races, so removing the check is acceptable. Add comment to racy code. [songmuchun@bytedance.com: remove set_page_huge_active() declaration from include/linux/hugetlb.h] Link: https://lkml.kernel.org/r/CAMZfGtUda+KoAZscU0718TN61cSFwp4zy=y2oZ=+6Z2TAZZwng@mail.gmail.com Link: https://lkml.kernel.org/r/20210122195231.324857-3-mike.kravetz@oracle.comSigned-off-by:
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Mike Kravetz authored
Patch series "create hugetlb flags to consolidate state", v3. While discussing a series of hugetlb fixes in [1], it became evident that the hugetlb specific page state information is stored in a somewhat haphazard manner. Code dealing with state information would be easier to read, understand and maintain if this information was stored in a consistent manner. This series uses page.private of the hugetlb head page for storing a set of hugetlb specific page flags. Routines are priovided for test, set and clear of the flags. [1] https://lore.kernel.org/r/20210106084739.63318-1-songmuchun@bytedance.com This patch (of 4): As hugetlbfs evolved, state information about hugetlb pages was added. One 'convenient' way of doing this was to use available fields in tail pages. Over time, it has become difficult to know the meaning or contents of fields simply by looking at a small bit of code. Sometimes, the naming is just confusing. For example: The PagePrivate flag indicates a huge page reservation was consumed and needs to be restored if an error is encountered and the page is freed before it is instantiated. The page.private field contains the pointer to a subpool if the page is associated with one. In an effort to make the code more readable, use page.private to contain hugetlb specific page flags. These flags will have test, set and clear functions similar to those used for 'normal' page flags. More importantly, an enum of flag values will be created with names that actually reflect their purpose. In this patch, - Create infrastructure for hugetlb specific page flag functions - Move subpool pointer to page[1].private to make way for flags Create routines with meaningful names to modify subpool field - Use new HPageRestoreReserve flag instead of PagePrivate Conversion of other state information will happen in subsequent patches. Link: https://lkml.kernel.org/r/20210122195231.324857-1-mike.kravetz@oracle.com Link: https://lkml.kernel.org/r/20210122195231.324857-2-mike.kravetz@oracle.comSigned-off-by:
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Oscar Salvador authored
The premise of the refault distance is that it can be seen as a deficit of the inactive list space, so that if the inactive list would have had (R - E) more slots, the page would not have been evicted but promoted to the active list instead. However, the way the code is ordered right now set us to be off by one, so the real number of slots would be (R - E) + 1. I stumbled upon this when trying to understand the code and it puzzled me that the comments did not match what the code did. This it not an issue at all since evictions and refaults tend to happen in a number large enough that being off-by-one does not have any impact - and since the compiler and CPUs are free to rearrange the execution sequence anyway. But as Johannes says, it is better to re-arrange the code in the proper order since otherwise would be misleading to somebody who is actively reading and trying to understand the logic of the code - like it happened to me. Link: https://lkml.kernel.org/r/20210201060651.3781-1-osalvador@suse.deSigned-off-by:
Johannes Weiner <hannes@cmpxchg.org> Acked-by:
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Yu Zhao authored
All other references to the function were removed after commit b910718a ("mm: vmscan: detect file thrashing at the reclaim root"). Link: https://lore.kernel.org/linux-mm/20201207220949.830352-11-yuzhao@google.com/ Link: https://lkml.kernel.org/r/20210122220600.906146-11-yuzhao@google.comSigned-off-by:
Yu Zhao <yuzhao@google.com> Reviewed-by:
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Yu Zhao authored
All other references to the function were removed after commit a892cb6b ("mm/vmscan.c: use update_lru_size() in update_lru_sizes()"). Link: https://lore.kernel.org/linux-mm/20201207220949.830352-10-yuzhao@google.com/ Link: https://lkml.kernel.org/r/20210122220600.906146-10-yuzhao@google.comSigned-off-by:
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Yu Zhao authored
We've removed all other references to this function. Link: https://lore.kernel.org/linux-mm/20201207220949.830352-9-yuzhao@google.com/ Link: https://lkml.kernel.org/r/20210122220600.906146-9-yuzhao@google.comSigned-off-by:
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Yu Zhao authored
Move scattered VM_BUG_ONs to two essential places that cover all lru list additions and deletions. Link: https://lore.kernel.org/linux-mm/20201207220949.830352-8-yuzhao@google.com/ Link: https://lkml.kernel.org/r/20210122220600.906146-8-yuzhao@google.comSigned-off-by:
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Yu Zhao authored
Similar to page_off_lru(), the new function does non-atomic clearing of PageLRU() in addition to PageActive() and PageUnevictable(), on a page that has no references left. If PageActive() and PageUnevictable() are both set, refuse to clear either and leave them to bad_page(). This is a behavior change that is meant to help debug. Link: https://lore.kernel.org/linux-mm/20201207220949.830352-7-yuzhao@google.com/ Link: https://lkml.kernel.org/r/20210122220600.906146-7-yuzhao@google.comSigned-off-by:
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Yu Zhao authored
The parameter is redundant in the sense that it can be potentially extracted from the "struct page" parameter by page_lru(). We need to make sure that existing PageActive() or PageUnevictable() remains until the function returns. A few places don't conform, and simple reordering fixes them. This patch may have left page_off_lru() seemingly odd, and we'll take care of it in the next patch. Link: https://lore.kernel.org/linux-mm/20201207220949.830352-6-yuzhao@google.com/ Link: https://lkml.kernel.org/r/20210122220600.906146-6-yuzhao@google.comSigned-off-by:
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Yu Zhao authored
The parameter is redundant in the sense that it can be extracted from the "struct page" parameter by page_lru() correctly. Link: https://lore.kernel.org/linux-mm/20201207220949.830352-5-yuzhao@google.com/ Link: https://lkml.kernel.org/r/20210122220600.906146-5-yuzhao@google.comSigned-off-by:
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Yu Zhao authored
The "enum lru_list" parameter to add_page_to_lru_list() and add_page_to_lru_list_tail() is redundant in the sense that it can be extracted from the "struct page" parameter by page_lru(). A caveat is that we need to make sure PageActive() or PageUnevictable() is correctly set or cleared before calling these two functions. And they are indeed. Link: https://lore.kernel.org/linux-mm/20201207220949.830352-4-yuzhao@google.com/ Link: https://lkml.kernel.org/r/20210122220600.906146-4-yuzhao@google.comSigned-off-by:
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Yu Zhao authored
These functions will call page_lru() in the following patches. Move them below page_lru() to avoid the forward declaration. Link: https://lore.kernel.org/linux-mm/20201207220949.830352-3-yuzhao@google.com/ Link: https://lkml.kernel.org/r/20210122220600.906146-3-yuzhao@google.comSigned-off-by:
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Yu Zhao authored
Patch series "mm: lru related cleanups", v2. The cleanups are intended to reduce the verbosity in lru list operations and make them less error-prone. A typical example would be how the patches change __activate_page(): static void __activate_page(struct page *page, struct lruvec *lruvec) { if (!PageActive(page) && !PageUnevictable(page)) { - int lru = page_lru_base_type(page); int nr_pages = thp_nr_pages(page); - del_page_from_lru_list(page, lruvec, lru); + del_page_from_lru_list(page, lruvec); SetPageActive(page); - lru += LRU_ACTIVE; - add_page_to_lru_list(page, lruvec, lru); + add_page_to_lru_list(page, lruvec); trace_mm_lru_activate(page); There are a few more places like __activate_page() and they are unnecessarily repetitive in terms of figuring out which list a page should be added onto or deleted from. And with the duplicated code removed, they are easier to read, IMO. Patch 1 to 5 basically cover the above. Patch 6 and 7 make code more robust by improving bug reporting. Patch 8, 9 and 10 take care of some dangling helpers left in header files. This patch (of 10): There is add_page_to_lru_list(), and move_pages_to_lru() should reuse it, not duplicate it. Link: https://lkml.kernel.org/r/20210122220600.906146-1-yuzhao@google.com Link: https://lore.kernel.org/linux-mm/20201207220949.830352-2-yuzhao@google.com/ Link: https://lkml.kernel.org/r/20210122220600.906146-2-yuzhao@google.comSigned-off-by:
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