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Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: cHGAuMmC2ySh4FxR6N+nJkupnIXTxZG21IpH5UnnXrlU9lez5fOAHph7Z0iw83EvdRQ7Uzoc9TjREF7rR/XyCA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM4PR12MB7621 X-Rspam-User: X-Rspamd-Queue-Id: 217931C0009 X-Stat-Signature: xu3smz3yatqahtx5jgbdgozwcfs39k47 X-Rspamd-Server: rspam06 X-HE-Tag: 1779316584-908686 X-HE-Meta: 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 i1aydqaj 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2026-05-20 at 21:57 +1000, Li Zhe wrote... > On Wed, 20 May 2026 09:20:18 +0300, rppt@kernel.org wrote: > > > On Mon, May 18, 2026 at 04:57:00PM +0800, Li Zhe wrote: > > > On Mon, 18 May 2026 09:23:33 +0300, rppt@kernel.org wrote: > > > > On Fri, May 15, 2026 at 04:20:41PM +0800, Li Zhe wrote: > > > > > > > > > > Performance > > > > > =========== > > > > > nd_pmem rebind, 100 GB fsdax namespace, map=dev > > > > > Base(v7.1-rc3): > > > > > First binding: 1486 ms > > > > > Average of subsequent rebinds: 273.52 ms > > > > > Full series: > > > > > First binding: 1272 ms > > > > > Average of subsequent rebinds: 104.59 ms > > > > > > > > > > dax_pmem rebind, 100 GB devdax namespace, align=2097152 > > > > > Base(v7.1-rc3): > > > > > First binding: 1515 ms > > > > > Average of subsequent rebinds: 313.45 ms > > > > > Full series: > > > > > First binding: 1286 ms > > > > > Average of subsequent rebinds: 116.93 ms > > > > > > > > This is really good improvement! > > > > > > > > It would be also interesting to see how the template approach would improve > > > > "normal" memory map initialization. > > > > > > I also experimented with this approach earlier. Unfortunately, in the > > > normal memory map initialization path, functions such as > > > deferred_free_pages() are invoked shortly after struct page > > > initialization, and this function performs both read and write accesses > > > to members of the struct page. > > > > > > Non-temporal stores via MOVNTI are primarily beneficial for streaming > > > write operations, where the cache lines written are not expected to be > > > reused by the CPU in the near future. In this case, however, data > > > written using MOVNTI is immediately accessed again through regular load > > > and store instructions. This results in an access pattern that resembles > > > a write-then-reuse workload rather than a pure streaming store. > > > > > > Consequently, non-temporal stores do not deliver the expected reduction > > > in cache pollution, and using MOVNTI provides no measurable performance > > > benefit for this particular workload. > > > > We can split initialization and freeing into separate loops if there is > > overall benefit, but this needs to be verified on other major architectures > > as well. > > I agree with your point. > > > > That said, a template-based approach can still accelerate initialization. > > > Based on measurements from this patchset, it should improve performance > > > on the generic path by roughly 10%. I would appreciate feedback on > > > whether such an optimization is still considered useful. > > > > Improving the memory map initialization by 10% is valuable. Agree with that - GPUs have to hotplug 100's GB of ZONE_DEVICE memory so any improvement here is valuable. Thanks for looking at it. - Alistair > Thank you for your feedback. I will try the optimization after finishing > the current patchset. > > Thanks, > Zhe >