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From: Suren Baghdasaryan <surenb@google.com>
To: akpm@linux-foundation.org
Cc: michel@lespinasse.org, jglisse@google.com, mhocko@suse.com,
	vbabka@suse.cz,  hannes@cmpxchg.org, mgorman@techsingularity.net,
	dave@stgolabs.net,  willy@infradead.org, liam.howlett@oracle.com,
	peterz@infradead.org,  ldufour@linux.ibm.com, paulmck@kernel.org,
	mingo@redhat.com, will@kernel.org,  luto@kernel.org,
	songliubraving@fb.com, peterx@redhat.com, david@redhat.com,
	 dhowells@redhat.com, hughd@google.com, bigeasy@linutronix.de,
	 kent.overstreet@linux.dev, punit.agrawal@bytedance.com,
	lstoakes@gmail.com,  peterjung1337@gmail.com,
	rientjes@google.com, chriscli@google.com,
	 axelrasmussen@google.com, joelaf@google.com, minchan@google.com,
	 rppt@kernel.org, jannh@google.com, shakeelb@google.com,
	tatashin@google.com,  edumazet@google.com, gthelen@google.com,
	gurua@google.com,  arjunroy@google.com, soheil@google.com,
	leewalsh@google.com, posk@google.com,
	 michalechner92@googlemail.com, linux-mm@kvack.org,
	 linux-arm-kernel@lists.infradead.org,
	linuxppc-dev@lists.ozlabs.org,  x86@kernel.org,
	linux-kernel@vger.kernel.org, kernel-team@android.com,
	 Liam Howlett <Liam.Howlett@oracle.com>,
	Suren Baghdasaryan <surenb@google.com>
Subject: [PATCH v4 04/33] maple_tree: remove extra smp_wmb() from mas_dead_leaves()
Date: Mon, 27 Feb 2023 09:36:03 -0800	[thread overview]
Message-ID: <20230227173632.3292573-5-surenb@google.com> (raw)
In-Reply-To: <20230227173632.3292573-1-surenb@google.com>

From: Liam Howlett <Liam.Howlett@oracle.com>

The call to mte_set_dead_node() before the smp_wmb() already calls
smp_wmb() so this is not needed.  This is an optimization for the RCU
mode of the maple tree.

Fixes: 54a611b60590 ("Maple Tree: add new data structure")
Signed-off-by: Liam Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
---
 lib/maple_tree.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 44d6ce30b28e..3d5ab02f981a 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -5517,7 +5517,6 @@ unsigned char mas_dead_leaves(struct ma_state *mas, void __rcu **slots,
 			break;
 
 		mte_set_node_dead(entry);
-		smp_wmb(); /* Needed for RCU */
 		node->type = type;
 		rcu_assign_pointer(slots[offset], node);
 	}
-- 
2.39.2.722.g9855ee24e9-goog



  parent reply	other threads:[~2023-02-27 17:36 UTC|newest]

Thread overview: 72+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-27 17:35 [PATCH v4 00/33] Per-VMA locks Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 01/33] maple_tree: Be more cautious about dead nodes Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 02/33] maple_tree: Detect dead nodes in mas_start() Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 03/33] maple_tree: Fix freeing of nodes in rcu mode Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan [this message]
2023-02-27 17:36 ` [PATCH v4 05/33] maple_tree: Fix write memory barrier of nodes once dead for RCU mode Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 06/33] maple_tree: Add smp_rmb() to dead node detection Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 07/33] maple_tree: Add RCU lock checking to rcu callback functions Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 08/33] mm: Enable maple tree RCU mode by default Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 09/33] mm: introduce CONFIG_PER_VMA_LOCK Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 10/33] mm: rcu safe VMA freeing Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 11/33] mm: move mmap_lock assert function definitions Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 12/33] mm: add per-VMA lock and helper functions to control it Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 13/33] mm: mark VMA as being written when changing vm_flags Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 14/33] mm/mmap: move vma_prepare before vma_adjust_trans_huge Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 15/33] mm/khugepaged: write-lock VMA while collapsing a huge page Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 16/33] mm/mmap: write-lock VMAs in vma_prepare before modifying them Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 17/33] mm/mremap: write-lock VMA while remapping it to a new address range Suren Baghdasaryan
2023-03-01  7:01   ` Hyeonggon Yoo
2023-02-27 17:36 ` [PATCH v4 18/33] mm: write-lock VMAs before removing them from VMA tree Suren Baghdasaryan
2023-03-01  7:43   ` Hyeonggon Yoo
2023-03-01  7:56     ` Hyeonggon Yoo
2023-03-01 18:34       ` Suren Baghdasaryan
2023-03-01 18:42         ` Suren Baghdasaryan
2023-03-02  0:53           ` Hyeonggon Yoo
2023-03-02  2:21             ` Suren Baghdasaryan
2023-03-01 19:07         ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 19/33] mm: conditionally write-lock VMA in free_pgtables Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 20/33] kernel/fork: assert no VMA readers during its destruction Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 21/33] mm/mmap: prevent pagefault handler from racing with mmu_notifier registration Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 22/33] mm: introduce vma detached flag Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 23/33] mm: introduce lock_vma_under_rcu to be used from arch-specific code Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 24/33] mm: fall back to mmap_lock if vma->anon_vma is not yet set Suren Baghdasaryan
2023-03-01  9:54   ` Hyeonggon Yoo
2023-02-27 17:36 ` [PATCH v4 25/33] mm: add FAULT_FLAG_VMA_LOCK flag Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 26/33] mm: prevent do_swap_page from handling page faults under VMA lock Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 27/33] mm: prevent userfaults to be handled under per-vma lock Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 28/33] mm: introduce per-VMA lock statistics Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 29/33] x86/mm: try VMA lock-based page fault handling first Suren Baghdasaryan
2023-06-29 14:40   ` Jiri Slaby
2023-06-29 15:30     ` Suren Baghdasaryan
2023-06-30  6:35       ` Jiri Slaby
2023-06-30  8:28         ` Jiri Slaby
2023-06-30  8:43           ` Jiri Slaby
2023-06-30 17:40             ` Suren Baghdasaryan
2023-07-03 10:47               ` Jiri Slaby
2023-07-03 13:52                 ` Holger Hoffstätte
2023-07-03 14:45                   ` Suren Baghdasaryan
2023-07-03 15:24                     ` Suren Baghdasaryan
2023-07-03 18:28                       ` Suren Baghdasaryan
2023-07-05 22:15                   ` Suren Baghdasaryan
2023-07-05 22:37                     ` Holger Hoffstätte
2023-07-05 22:55                       ` Suren Baghdasaryan
2023-07-06 14:27                         ` Holger Hoffstätte
2023-07-06 16:11                           ` Suren Baghdasaryan
2023-07-07  2:23                             ` Suren Baghdasaryan
2023-07-07  4:40                               ` Suren Baghdasaryan
2023-07-11  6:20                     ` Jiri Slaby
2023-06-29 17:06     ` Linux regression tracking #adding (Thorsten Leemhuis)
2023-07-03  9:58     ` Linux regression tracking (Thorsten Leemhuis)
2023-02-27 17:36 ` [PATCH v4 30/33] arm64/mm: " Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 31/33] powerc/mm: " Suren Baghdasaryan
2023-03-06 15:42   ` [PATCH] powerpc/mm: fix mmap_lock bad unlock Laurent Dufour
2023-03-06 20:25   ` [PATCH v4 31/33] powerc/mm: try VMA lock-based page fault handling first Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 32/33] mm/mmap: free vm_area_struct without call_rcu in exit_mmap Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 33/33] mm: separate vma->lock from vm_area_struct Suren Baghdasaryan
2023-07-11 10:35 ` [PATCH v4 00/33] Per-VMA locks Leon Romanovsky
2023-07-11 10:39   ` Vlastimil Babka
2023-07-11 11:01     ` Leon Romanovsky
2023-07-11 11:09       ` Leon Romanovsky
2023-07-11 16:35         ` Suren Baghdasaryan
2023-07-11 17:14           ` Leon Romanovsky

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