* + mm-migration-reduce-the-rcu-lock-duration.patch added to -mm tree
@ 2022-04-25 19:10 Andrew Morton
2022-04-26 7:10 ` ying.huang
0 siblings, 1 reply; 2+ messages in thread
From: Andrew Morton @ 2022-04-25 19:10 UTC (permalink / raw)
To: mm-commits, ying.huang, songmuchun, naoya.horiguchi,
mike.kravetz, mgorman, hch, dhowells, david, cl, linmiaohe, akpm
The patch titled
Subject: mm/migration: reduce the rcu lock duration
has been added to the -mm tree. Its filename is
mm-migration-reduce-the-rcu-lock-duration.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-migration-reduce-the-rcu-lock-duration.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-migration-reduce-the-rcu-lock-duration.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Miaohe Lin <linmiaohe@huawei.com>
Subject: mm/migration: reduce the rcu lock duration
Patch series "A few cleanup and fixup patches for migration", v2.
This series contains a few patches to remove unneeded lock page and
PageMovable check, reduce the rcu lock duration. Also we fix potential
pte_unmap on an not mapped pte. More details can be found in the
respective changelogs.
This patch (of 4):
rcu_read_lock is required by grabbing the task refcount but it's not
needed for ptrace_may_access. So we could release the rcu lock after task
refcount is successfully grabbed to reduce the rcu holding time.
Link: https://lkml.kernel.org/r/20220425132723.34824-1-linmiaohe@huawei.com
Link: https://lkml.kernel.org/r/20220425132723.34824-2-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Huang Ying <ying.huang@intel.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/migrate.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
--- a/mm/migrate.c~mm-migration-reduce-the-rcu-lock-duration
+++ a/mm/migrate.c
@@ -1902,17 +1902,16 @@ static struct mm_struct *find_mm_struct(
return ERR_PTR(-ESRCH);
}
get_task_struct(task);
+ rcu_read_unlock();
/*
* Check if this process has the right to modify the specified
* process. Use the regular "ptrace_may_access()" checks.
*/
if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) {
- rcu_read_unlock();
mm = ERR_PTR(-EPERM);
goto out;
}
- rcu_read_unlock();
mm = ERR_PTR(security_task_movememory(task));
if (IS_ERR(mm))
_
Patches currently in -mm which might be from linmiaohe@huawei.com are
mm-shmem-make-shmem_init-return-void.patch
mm-memcg-remove-unneeded-nr_scanned.patch
mm-mmapc-use-helper-mlock_future_check.patch
mm-mremap-use-helper-mlock_future_check.patch
mm-mremap-avoid-unneeded-do_munmap-call.patch
mm-memory-failurec-minor-cleanup-for-hwpoisonhandlable.patch
mm-memory-failurec-dissolve-truncated-hugetlb-page.patch
mm-vmscan-remove-obsolete-comment-in-get_scan_count.patch
mm-vmscan-fix-comment-for-current_may_throttle.patch
mm-vmscan-fix-comment-for-isolate_lru_pages.patch
mm-z3fold-declare-z3fold_mount-with-__init.patch
mm-z3fold-remove-obsolete-comment-in-z3fold_alloc.patch
mm-z3fold-minor-clean-up-for-z3fold_free.patch
mm-z3fold-remove-unneeded-page_mapcount_reset-and-clearpageprivate.patch
mm-z3fold-remove-confusing-local-variable-l-reassignment.patch
mm-z3fold-move-decrement-of-pool-pages_nr-into-__release_z3fold_page.patch
mm-z3fold-remove-redundant-list_del_init-of-zhdr-buddy-in-z3fold_free.patch
mm-z3fold-remove-unneeded-page_headless-check-in-free_handle.patch
mm-compaction-use-helper-isolation_suitable.patch
drivers-base-nodec-fix-compaction-sysfs-file-leak.patch
mm-mempolicy-clean-up-the-code-logic-in-queue_pages_pte_range.patch
mm-migration-remove-unneeded-local-variable-mapping_locked.patch
mm-migration-remove-unneeded-local-variable-page_lru.patch
mm-migration-use-helper-function-vma_lookup-in-add_page_for_migration.patch
mm-migration-use-helper-macro-min-in-do_pages_stat.patch
mm-migration-avoid-unneeded-nodemask_t-initialization.patch
mm-migration-remove-some-duplicated-codes-in-migrate_pages.patch
mm-migration-fix-potential-page-refcounts-leak-in-migrate_pages.patch
mm-migration-fix-potential-invalid-node-access-for-reclaim-based-migration.patch
mm-migration-fix-possible-do_pages_stat_array-racing-with-memory-offline.patch
mm-madvise-fix-potential-pte_unmap_unlock-pte-error.patch
mm-madvise-free-hwpoison-and-swapin-error-entry-in-madvise_free_pte_range.patch
mm-compaction-remove-unneeded-return-value-of-kcompactd_run.patch
mm-compaction-remove-unneeded-pfn-update.patch
mm-compaction-remove-unneeded-assignment-to-isolate_start_pfn.patch
mm-compaction-clean-up-comment-for-sched-contention.patch
mm-compaction-clean-up-comment-about-suitable-migration-target-recheck.patch
mm-compaction-use-compact_cluster_max-in-compactionc.patch
mm-compaction-use-helper-compound_nr-in-isolate_migratepages_block.patch
mm-compaction-clean-up-comment-about-async-compaction-in-isolate_migratepages.patch
mm-compaction-avoid-possible-null-pointer-dereference-in-kcompactd_cpu_online.patch
mm-compaction-make-compaction_zonelist_suitable-return-false-when-compact_success.patch
mm-compaction-simplify-the-code-in-__compact_finished.patch
mm-compaction-make-sure-highest-is-above-the-min_pfn.patch
mm-swapfile-unuse_pte-can-map-random-data-if-swap-read-fails.patch
mm-swapfile-fix-lost-swap-bits-in-unuse_pte.patch
mm-migration-reduce-the-rcu-lock-duration.patch
mm-migration-remove-unneeded-lock-page-and-pagemovable-check.patch
mm-migration-return-errno-when-isolate_huge_page-failed.patch
mm-migration-fix-potential-pte_unmap-on-an-not-mapped-pte.patch
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: + mm-migration-reduce-the-rcu-lock-duration.patch added to -mm tree
2022-04-25 19:10 + mm-migration-reduce-the-rcu-lock-duration.patch added to -mm tree Andrew Morton
@ 2022-04-26 7:10 ` ying.huang
0 siblings, 0 replies; 2+ messages in thread
From: ying.huang @ 2022-04-26 7:10 UTC (permalink / raw)
To: Andrew Morton, mm-commits, songmuchun, naoya.horiguchi,
mike.kravetz, mgorman, hch, dhowells, david, cl, linmiaohe
Hi, Andrew,
On Mon, 2022-04-25 at 12:10 -0700, Andrew Morton wrote:
> The patch titled
> Subject: mm/migration: reduce the rcu lock duration
> has been added to the -mm tree. Its filename is
> mm-migration-reduce-the-rcu-lock-duration.patch
>
> This patch should soon appear at
> https://ozlabs.org/~akpm/mmots/broken-out/mm-migration-reduce-the-rcu-lock-duration.patch
> and later at
> https://ozlabs.org/~akpm/mmotm/broken-out/mm-migration-reduce-the-rcu-lock-duration.patch
>
> Before you just go and hit "reply", please:
> a) Consider who else should be cc'ed
> b) Prefer to cc a suitable mailing list as well
> c) Ideally: find the original patch on the mailing list and do a
> reply-to-all to that, adding suitable additional cc's
>
> *** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
>
> The -mm tree is included into linux-next and is updated
> there every 3-4 working days
>
> ------------------------------------------------------
> From: Miaohe Lin <linmiaohe@huawei.com>
> Subject: mm/migration: reduce the rcu lock duration
>
> Patch series "A few cleanup and fixup patches for migration", v2.
>
> This series contains a few patches to remove unneeded lock page and
> PageMovable check, reduce the rcu lock duration. Also we fix potential
> pte_unmap on an not mapped pte. More details can be found in the
> respective changelogs.
>
>
> This patch (of 4):
>
> rcu_read_lock is required by grabbing the task refcount but it's not
> needed for ptrace_may_access. So we could release the rcu lock after task
> refcount is successfully grabbed to reduce the rcu holding time.
>
> Link: https://lkml.kernel.org/r/20220425132723.34824-1-linmiaohe@huawei.com
> Link: https://lkml.kernel.org/r/20220425132723.34824-2-linmiaohe@huawei.com
> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
> Reviewed-by: Muchun Song <songmuchun@bytedance.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Cc: Huang Ying <ying.huang@intel.com>
> Cc: David Howells <dhowells@redhat.com>
> Cc: Christoph Lameter <cl@linux.com>
> Cc: Mike Kravetz <mike.kravetz@oracle.com>
> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
> Cc: David Hildenbrand <david@redhat.com>
> Cc: Mel Gorman <mgorman@techsingularity.net>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
I think that there is still a remaining issue to be addressed for this
patch as in the following threads,
https://lore.kernel.org/linux-mm/8735ju7as9.fsf@yhuang6-desk2.ccr.corp.intel.com/
https://lore.kernel.org/lkml/34f3aff7-0111-a8d6-a559-92bf6d0bd62a@huawei.com/
Best Regards,
Huang, Ying
> ---
>
> mm/migrate.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> --- a/mm/migrate.c~mm-migration-reduce-the-rcu-lock-duration
> +++ a/mm/migrate.c
> @@ -1902,17 +1902,16 @@ static struct mm_struct *find_mm_struct(
> return ERR_PTR(-ESRCH);
> }
> get_task_struct(task);
> + rcu_read_unlock();
>
>
>
>
> /*
> * Check if this process has the right to modify the specified
> * process. Use the regular "ptrace_may_access()" checks.
> */
> if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) {
> - rcu_read_unlock();
> mm = ERR_PTR(-EPERM);
> goto out;
> }
> - rcu_read_unlock();
>
>
>
>
> mm = ERR_PTR(security_task_movememory(task));
> if (IS_ERR(mm))
> _
>
> Patches currently in -mm which might be from linmiaohe@huawei.com are
>
> mm-shmem-make-shmem_init-return-void.patch
> mm-memcg-remove-unneeded-nr_scanned.patch
> mm-mmapc-use-helper-mlock_future_check.patch
> mm-mremap-use-helper-mlock_future_check.patch
> mm-mremap-avoid-unneeded-do_munmap-call.patch
> mm-memory-failurec-minor-cleanup-for-hwpoisonhandlable.patch
> mm-memory-failurec-dissolve-truncated-hugetlb-page.patch
> mm-vmscan-remove-obsolete-comment-in-get_scan_count.patch
> mm-vmscan-fix-comment-for-current_may_throttle.patch
> mm-vmscan-fix-comment-for-isolate_lru_pages.patch
> mm-z3fold-declare-z3fold_mount-with-__init.patch
> mm-z3fold-remove-obsolete-comment-in-z3fold_alloc.patch
> mm-z3fold-minor-clean-up-for-z3fold_free.patch
> mm-z3fold-remove-unneeded-page_mapcount_reset-and-clearpageprivate.patch
> mm-z3fold-remove-confusing-local-variable-l-reassignment.patch
> mm-z3fold-move-decrement-of-pool-pages_nr-into-__release_z3fold_page.patch
> mm-z3fold-remove-redundant-list_del_init-of-zhdr-buddy-in-z3fold_free.patch
> mm-z3fold-remove-unneeded-page_headless-check-in-free_handle.patch
> mm-compaction-use-helper-isolation_suitable.patch
> drivers-base-nodec-fix-compaction-sysfs-file-leak.patch
> mm-mempolicy-clean-up-the-code-logic-in-queue_pages_pte_range.patch
> mm-migration-remove-unneeded-local-variable-mapping_locked.patch
> mm-migration-remove-unneeded-local-variable-page_lru.patch
> mm-migration-use-helper-function-vma_lookup-in-add_page_for_migration.patch
> mm-migration-use-helper-macro-min-in-do_pages_stat.patch
> mm-migration-avoid-unneeded-nodemask_t-initialization.patch
> mm-migration-remove-some-duplicated-codes-in-migrate_pages.patch
> mm-migration-fix-potential-page-refcounts-leak-in-migrate_pages.patch
> mm-migration-fix-potential-invalid-node-access-for-reclaim-based-migration.patch
> mm-migration-fix-possible-do_pages_stat_array-racing-with-memory-offline.patch
> mm-madvise-fix-potential-pte_unmap_unlock-pte-error.patch
> mm-madvise-free-hwpoison-and-swapin-error-entry-in-madvise_free_pte_range.patch
> mm-compaction-remove-unneeded-return-value-of-kcompactd_run.patch
> mm-compaction-remove-unneeded-pfn-update.patch
> mm-compaction-remove-unneeded-assignment-to-isolate_start_pfn.patch
> mm-compaction-clean-up-comment-for-sched-contention.patch
> mm-compaction-clean-up-comment-about-suitable-migration-target-recheck.patch
> mm-compaction-use-compact_cluster_max-in-compactionc.patch
> mm-compaction-use-helper-compound_nr-in-isolate_migratepages_block.patch
> mm-compaction-clean-up-comment-about-async-compaction-in-isolate_migratepages.patch
> mm-compaction-avoid-possible-null-pointer-dereference-in-kcompactd_cpu_online.patch
> mm-compaction-make-compaction_zonelist_suitable-return-false-when-compact_success.patch
> mm-compaction-simplify-the-code-in-__compact_finished.patch
> mm-compaction-make-sure-highest-is-above-the-min_pfn.patch
> mm-swapfile-unuse_pte-can-map-random-data-if-swap-read-fails.patch
> mm-swapfile-fix-lost-swap-bits-in-unuse_pte.patch
> mm-migration-reduce-the-rcu-lock-duration.patch
> mm-migration-remove-unneeded-lock-page-and-pagemovable-check.patch
> mm-migration-return-errno-when-isolate_huge_page-failed.patch
> mm-migration-fix-potential-pte_unmap-on-an-not-mapped-pte.patch
>
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2022-04-26 7:11 UTC | newest]
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2022-04-25 19:10 + mm-migration-reduce-the-rcu-lock-duration.patch added to -mm tree Andrew Morton
2022-04-26 7:10 ` ying.huang
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