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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: 9pfr/T2pHZZVqwbGwqregqoGjVwJAjDQy/7wXoJ4w+kNVSSDklFDzHGPgc60ukUGOiy3bOl1TzXZsYCCsYVONjZw6XvBKYN2e0V3O8PMsmiZy3FMZtKkya46WsPuUpgtwhnAG0VMNv5FF9vEds1guU0buxixkZiug1UwSKqlLy20eZrR1lULBP+FUDKzG2opxveh0Lw13qcqqgWMpBOX0k/bAnhRxBanxPLD/UoOmmisXdnCleB1sGqJg4j4bl4XQb6opoNl8cIryl1I+us/crLHlLawnEgZV70ITQ5/xaWQrednJWjAZhHGxeEeIRpf2U1TX5/osn+qbSjS5F29h0A7C4vnNYnlxjyKfa6GYZlKdE1ELMu0BgnVvOSs/6VViVPcHCW9inBLD3jJboCsqh7mYe1I3p2NWFprel6pQakyZ/eOPnyXkMf6m5RlixQu X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 20 Feb 2026 19:10:01.8390 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: e3982adc-b80b-4a68-7610-08de70b3a5f2 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[satlexmb08.amd.com] X-MS-Exchange-CrossTenant-AuthSource: CH1PEPF0000A348.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH0PR12MB7885 On 2/11/2026 9:22 AM, Dmitry Ilvokhin wrote: > Zone lock contention can significantly impact allocation and > reclaim latency, as it is a central synchronization point in > the page allocator and reclaim paths. Improved visibility into > its behavior is therefore important for diagnosing performance > issues in memory-intensive workloads. > > On some production workloads at Meta, we have observed noticeable > zone lock contention. Deeper analysis of lock holders and waiters > is currently difficult with existing instrumentation. > > While generic lock contention_begin/contention_end tracepoints > cover the slow path, they do not provide sufficient visibility > into lock hold times. In particular, the lack of a release-side > event makes it difficult to identify long lock holders and > correlate them with waiters. As a result, distinguishing between > short bursts of contention and pathological long hold times > requires additional instrumentation. > > This patch series adds dedicated tracepoint instrumentation to > zone lock, following the existing mmap_lock tracing model. > > The goal is to enable detailed holder/waiter analysis and lock > hold time measurements without affecting the fast path when > tracing is disabled. > > The series is structured as follows: > > 1. Introduce zone lock wrappers. > 2. Mechanically convert zone lock users to the wrappers. > 3. Convert compaction to use the wrappers (requires minor > restructuring of compact_lock_irqsave()). > 4. Add zone lock tracepoints. I think you can improve the flow of this series if reorder as follows: 1. Introduce zone lock wrappers 4. Add zone lock tracepoints 2. Mechanically convert zone lock users to the wrappers 3. Convert compaction to use the wrappers... and possibly squash 1 & 4 (though that might be too big of a patch). It's better to introduce the wrappers and their tracepoints together before the reviewer (i.e. me) forgets what was added in patch 1 by the time they get to patch 4. Thanks, Ben