From: "Garg, Shivank" <shivankg@amd.com>
To: Gregory Price <gourry@gourry.net>
Cc: akpm@linux-foundation.org, david@kernel.org,
lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com,
vbabka@kernel.org, willy@infradead.org, rppt@kernel.org,
surenb@google.com, mhocko@suse.com, ziy@nvidia.com,
matthew.brost@intel.com, joshua.hahnjy@gmail.com,
rakie.kim@sk.com, byungchul@sk.com, ying.huang@linux.alibaba.com,
apopple@nvidia.com, dave@stgolabs.net,
Jonathan.Cameron@huawei.com, rkodsara@amd.com, vkoul@kernel.org,
bharata@amd.com, sj@kernel.org, weixugc@google.com,
dan.j.williams@intel.com, rientjes@google.com,
xuezhengchu@huawei.com, yiannis@zptcorp.com,
dave.hansen@intel.com, hannes@cmpxchg.org, jhubbard@nvidia.com,
peterx@redhat.com, riel@surriel.com, shakeel.butt@linux.dev,
stalexan@redhat.com, tj@kernel.org, nifan.cxl@gmail.com,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Mike Day <michael.day@amd.com>
Subject: Re: [RFC PATCH v4 4/6] mm/migrate: add copy offload registration infrastructure
Date: Tue, 10 Mar 2026 15:37:47 +0530 [thread overview]
Message-ID: <84643d33-66bd-43b7-b3b0-cb6401a134e5@amd.com> (raw)
In-Reply-To: <aa8JTMda9oafjzcf@gourry-fedora-PF4VCD3F>
On 3/9/2026 11:24 PM, Gregory Price wrote:
> On Mon, Mar 09, 2026 at 12:07:29PM +0000, Shivank Garg wrote:
> ... snip ...
>>
>> Only one migrator can be active a time. A second registration returns
>> -EBUSY, and only the active migrator can stop itself. The static_call
>> dispatch is under SRCU so synchronize_srcu() in stop path guarantees
>> no in-flight copy before the module reference is dropped.
>>
> ... snip ...
>
>> @@ -1820,11 +1833,18 @@ static int migrate_pages_batch(struct list_head *from,
>>
>> +#ifdef CONFIG_MIGRATION_COPY_OFFLOAD
>> + /* Check if the offload driver wants to batch for this reason */
>> + if (static_branch_unlikely(&migrate_offload_enabled))
>> + do_batch = static_call(migrate_should_batch)(reason);
>> +#endif
>> +
>
> should the migrate_should_batch call also be done under srcu?
>
> In theory it's an incredibly small window, but there is a race window.
Yes, right.
thanks for pointing this out.
Best regards,
Shivank
next prev parent reply other threads:[~2026-03-10 10:08 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-09 12:07 [RFC PATCH v4 0/6] Accelerate page migration with batch copying and hardware offload Shivank Garg
2026-03-09 12:07 ` [RFC PATCH v4 1/6] mm: introduce folios_mc_copy() for batch folio copying Shivank Garg
2026-03-12 9:41 ` David Hildenbrand (Arm)
2026-03-15 18:09 ` Garg, Shivank
2026-03-09 12:07 ` [RFC PATCH v4 2/6] mm/migrate: skip data copy for already-copied folios Shivank Garg
2026-03-12 9:44 ` David Hildenbrand (Arm)
2026-03-15 18:25 ` Garg, Shivank
2026-03-23 12:20 ` David Hildenbrand (Arm)
2026-03-24 8:22 ` Huang, Ying
2026-04-03 11:08 ` Garg, Shivank
2026-04-07 6:52 ` Huang, Ying
2026-04-23 12:20 ` Garg, Shivank
2026-03-09 12:07 ` [RFC PATCH v4 3/6] mm/migrate: add batch-copy path in migrate_pages_batch Shivank Garg
2026-03-24 8:42 ` Huang, Ying
2026-04-03 11:09 ` Garg, Shivank
2026-03-09 12:07 ` [RFC PATCH v4 4/6] mm/migrate: add copy offload registration infrastructure Shivank Garg
2026-03-09 17:54 ` Gregory Price
2026-03-10 10:07 ` Garg, Shivank [this message]
2026-03-24 10:54 ` Huang, Ying
2026-04-03 11:11 ` Garg, Shivank
2026-04-07 7:40 ` Huang, Ying
2026-04-28 12:10 ` Garg, Shivank
2026-04-30 1:23 ` Huang, Ying
2026-03-09 12:07 ` [RFC PATCH v4 5/6] drivers/migrate_offload: add DMA batch copy driver (dcbm) Shivank Garg
2026-03-09 18:04 ` Gregory Price
2026-03-12 9:33 ` Garg, Shivank
2026-03-24 8:10 ` Huang, Ying
2026-04-03 11:06 ` Garg, Shivank
2026-04-23 12:10 ` Garg, Shivank
2026-04-23 14:13 ` Vinod Koul
2026-04-24 11:26 ` Garg, Shivank
2026-03-09 12:07 ` [RFC PATCH v4 6/6] mm/migrate: adjust NR_MAX_BATCHED_MIGRATION for testing Shivank Garg
2026-03-18 14:29 ` [RFC PATCH v4 0/6] Accelerate page migration with batch copying and hardware offload Garg, Shivank
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