Linaro-mm-sig June 2026

linaro-mm-sig@lists.linaro.org

135 participants
487 discussions

[PATCH v18 00/42] DEPT(DEPendency Tracker)

by Byungchul Park

I'm happy to see that DEPT reported real problems in practice: https://lore.kernel.org/lkml/6383cde5-cf4b-facf-6e07-1378a485657d@I-love.SA… https://lore.kernel.org/lkml/1674268856-31807-1-git-send-email-byungchul.pa… https://lore.kernel.org/all/b6e00e77-4a8c-4e05-ab79-266bf05fcc2d@igalia.com/ I’ve added documentation describing DEPT — this should help you understand what DEPT is and how it works. You can use DEPT simply by enabling CONFIG_DEPT and checking dmesg at runtime. --- Hi Linus and folks, I’ve been developing a tool to detect deadlock possibilities by tracking waits/events — rather than lock acquisition order — to cover all the synchronization mechanisms. To summarize the design rationale, starting from the problem statement, through analysis, to the solution: CURRENT STATUS -------------- Lockdep tracks lock acquisition order to identify deadlock conditions. Additionally, it tracks IRQ state changes — via {en,dis}able — to detect cases where locks are acquired unintentionally during interrupt handling. PROBLEM ------- Waits and their associated events that are never reachable can eventually lead to deadlocks. However, since Lockdep focuses solely on lock acquisition order, it has inherent limitations when handling waits and events. Moreover, by tracking only lock acquisition order, Lockdep cannot properly handle read locks or cross-event scenarios — such as wait_for_completion() and complete() — making it increasingly inadequate as a general-purpose deadlock detection tool. SOLUTION -------- Once again, waits and their associated events that are never reachable can eventually lead to deadlocks. The new solution, DEPT, focuses directly on waits and events. DEPT monitors waits and events, and reports them when any become unreachable. DEPT provides: * Correct handling of read locks. * Support for general waits and events. * Continuous operation, even after multiple reports. * Simple, intuitive annotation APIs. There are still false positives, and some are already being worked on for suppression. Especially splitting the folio class into several appropriate classes e.g. block device mapping class and regular file mapping class, is currently under active development by me and Yeoreum Yun. Anyway, these efforts will need to continue for a while, as we’ve seen with lockdep over two decades. DEPT is tagged as EXPERIMENTAL in Kconfig — meaning it’s not yet suitable for use as an automation tool. However, for those who are interested in using DEPT to analyze complex synchronization patterns and extract dependency insights, DEPT would be a great tool for the purpose. Thanks for your support and contributions to: Harry Yoo <harry.yoo(a)oracle.com> Gwan-gyeong Mun <gwan-gyeong.mun(a)intel.com> Yunseong Kim <ysk(a)kzalloc.com> Yeoreum Yun <yeoreum.yun(a)arm.com> FAQ --- Q. Is this the first attempt to solve this problem? A. No. The cross-release feature (commit b09be676e0ff2) attempted to address it — as a Lockdep extension. It was merged, but quickly reverted, because: While it uncovered valuable hidden issues, it also introduced false positives. Since these false positives mask further real problems with Lockdep — and developers strongly dislike them — the feature was rolled back. Q. Why wasn’t DEPT built as a Lockdep extension? A. Lockdep is the result of years of work by kernel developers — and is now very stable. But I chose to build DEPT separately, because: While reusing BFS(Breadth First Search) and Lockdep’s hashing is beneficial, the rest of the system must be rebuilt from scratch to align with DEPT’s wait-event model — since Lockdep was originally designed for tracking lock acquisition orders, not wait-event dependencies. Q. Do you plan to replace Lockdep entirely? A. Not at all — Lockdep still plays a vital role in validating correct lock usage. While its dependency-checking logic should eventually be superseded by DEPT, the rest of its functionality should stay. Q. Should we replace the dependency check immediately? A. Absolutely not. Lockdep’s stability is the result of years of hard work by kernel developers. Lockdep and DEPT should run side by side until DEPT matures. Q. Stronger detection often leads to more false positives — which was a major pain point when cross-release was added. Is DEPT designed to handle this? A. Yes. DEPT’s simple, generalized design enables flexible reporting — so while false positives still need fixing, they’re far less disruptive than they were under the Lockdep extension, cross-release. Q. Why not fix all false positives out-of-tree before merging? A. Since the affected subsystems span the entire kernel, like Lockdep, which has relied on annotations to avoid false positives over the last two decades, DEPT too will require the annotation efforts. Performing annotation work within the mainline will help us add annotations more appropriately and will also make DEPT a useful tool for a wider range of users more quickly. CONFIG_DEPT is marked EXPERIMENTAL, so it’s opt-in. Some users are already interested in using DEPT to analyze complex synchronization patterns and extract dependency insights. Byungchul --- Changes from v17: 1. Rebase on the mainline as of 2025 Dec 5. 2. Convert the documents' format from txt to rst. (feedbacked by Jonathan Corbet and Bagas Sanjaya) 3. Move the documents from 'Documentation/dependency' to 'Documentation/dev-tools'. (feedbakced by Jonathan Corbet) 4. Improve the documentation. (feedbacked by NeilBrown) 5. Use a common function, enter_from_user_mode(), instead of arch specific code, to notice context switch from user mode. (feedbacked by Dave Hansen, Mark Rutland, and Mark Brown) 6. Resolve the header dependency issue by using dept's internal header, instead of relocating 'struct llist_{head,node}' to another header. (feedbacked by Greg KH) 7. Improve page(or folio) usage type APIs. 8. Add rust helper for wait_for_completion(). (feedbacked by Guangbo Cui, Boqun Feng, and Danilo Krummrich) 9. Refine some commit messages. Changes from v16: 1. Rebase on v6.17. 2. Fix a false positive from rcu (by Yunseong Kim) 3. Introduce APIs to set page's usage, dept_set_page_usage() and dept_reset_page_usage() to avoid false positives. 4. Consider lock_page() as a potential wait unconditionally. 5. Consider folio_lock_killable() as a potential wait unconditionally. 6. Add support for tracking PG_writeback waits and events. 7. Fix two build errors due to the additional debug information added by dept. (by Yunseong Kim) Changes from v15: 1. Fix typo and improve comments and commit messages (feedbacked by ALOK TIWARI, Waiman Long, and kernel test robot). 2. Do not stop dept on detection of cicular dependency of recover event, allowing to keep reporting. 3. Add SK hynix to copyright. 4. Consider folio_lock() as a potential wait unconditionally. 5. Fix Kconfig dependency bug (feedbacked by kernel test rebot). 6. Do not suppress reports that involve classes even that have already involved in other reports, allowing to keep reporting. Changes from v14: 1. Rebase on the current latest, v6.15-rc6. 2. Refactor dept code. 3. With multi event sites for a single wait, even if an event forms a circular dependency, the event can be recovered by other event(or wake up) paths. Even though informing the circular dependency is worthy but it should be suppressed once informing it, if it doesn't lead an actual deadlock. So introduce APIs to annotate the relationship between event site and recover site, that are, event_site() and dept_recover_event(). 4. wait_for_completion() worked with dept map embedded in struct completion. However, it generates a few false positves since all the waits using the instance of struct completion, share the map and key. To avoid the false positves, make it not to share the map and key but each wait_for_completion() caller have its own key by default. Of course, external maps also can be used if needed. 5. Fix a bug about hardirq on/off tracing. 6. Implement basic unit test for dept. 7. Add more supports for dma fence synchronization. 8. Add emergency stop of dept e.g. on panic(). 9. Fix false positives by mmu_notifier_invalidate_*(). 10. Fix recursive call bug by DEPT_WARN_*() and DEPT_STOP(). 11. Fix trivial bugs in DEPT_WARN_*() and DEPT_STOP(). 12. Fix a bug that a spin lock, dept_pool_spin, is used in both contexts of irq disabled and enabled without irq disabled. 13. Suppress reports with classes, any of that already have been reported, even though they have different chains but being barely meaningful. 14. Print stacktrace of the wait that an event is now waking up, not only stacktrace of the event. 15. Make dept aware of lockdep_cmp_fn() that is used to avoid false positives in lockdep so that dept can also avoid them. 16. Do do_event() only if there are no ecxts have been delimited. 17. Fix a bug that was not synchronized for stage_m in struct dept_task, using a spin lock, dept_task()->stage_lock. 18. Fix a bug that dept didn't handle the case that multiple ttwus for a single waiter can be called at the same time e.i. a race issue. 19. Distinguish each kernel context from others, not only by system call but also by user oriented fault so that dept can work with more accuracy information about kernel context. That helps to avoid a few false positives. 20. Limit dept's working to x86_64 and arm64. Changes from v13: 1. Rebase on the current latest version, v6.9-rc7. 2. Add 'dept' documentation describing dept APIs. Changes from v12: 1. Refine the whole document for dept. 2. Add 'Interpret dept report' section in the document, using a deadlock report obtained in practice. Hope this version of document helps guys understand dept better. https://lore.kernel.org/lkml/6383cde5-cf4b-facf-6e07-1378a485657d@I-love.SA… https://lore.kernel.org/lkml/1674268856-31807-1-git-send-email-byungchul.pa… Changes from v11: 1. Add 'dept' documentation describing the concept of dept. 2. Rewrite the commit messages of the following commits for using weaker lockdep annotation, for better description. fs/jbd2: Use a weaker annotation in journal handling cpu/hotplug: Use a weaker annotation in AP thread (feedbacked by Thomas Gleixner) Changes from v10: 1. Fix noinstr warning when building kernel source. 2. dept has been reporting some false positives due to the folio lock's unfairness. Reflect it and make dept work based on dept annotaions instead of just wait and wake up primitives. 3. Remove the support for PG_writeback while working on 2. I will add the support later if needed. 4. dept didn't print stacktrace for [S] if the participant of a deadlock is not lock mechanism but general wait and event. However, it made hard to interpret the report in that case. So add support to print stacktrace of the requestor who asked the event context to run - usually a waiter of the event does it just before going to wait state. 5. Give up tracking raw_local_irq_{disable,enable}() since it totally messed up dept's irq tracking. So make it work in the same way as lockdep does. I will consider it once any false positives by those are observed again. 6. Change the manual rwsem_acquire_read(->j_trans_commit_map) annotation in fs/jbd2/transaction.c to the try version so that it works as much as it exactly needs. 7. Remove unnecessary 'inline' keyword in dept.c and add '__maybe_unused' to a needed place. Changes from v9: 1. Fix a bug. SDT tracking didn't work well because of my big mistake that I should've used waiter's map to indentify its class but it had been working with waker's one. FYI, PG_locked and PG_writeback weren't affected. They still worked well. (reported by YoungJun) Changes from v8: 1. Fix build error by adding EXPORT_SYMBOL(PG_locked_map) and EXPORT_SYMBOL(PG_writeback_map) for kernel module build - appologize for that. (reported by kernel test robot) 2. Fix build error by removing header file's circular dependency that was caused by "atomic.h", "kernel.h" and "irqflags.h", which I introduced - appolgize for that. (reported by kernel test robot) Changes from v7: 1. Fix a bug that cannot track rwlock dependency properly, introduced in v7. (reported by Boqun and lockdep selftest) 2. Track wait/event of PG_{locked,writeback} more aggressively assuming that when a bit of PG_{locked,writeback} is cleared there might be waits on the bit. (reported by Linus, Hillf and syzbot) 3. Fix and clean bad style code e.i. unnecessarily introduced a randome pattern and so on. (pointed out by Linux) 4. Clean code for applying dept to wait_for_completion(). Changes from v6: 1. Tie to task scheduler code to track sleep and try_to_wake_up() assuming sleeps cause waits, try_to_wake_up()s would be the events that those are waiting for, of course with proper dept annotations, sdt_might_sleep_weak(), sdt_might_sleep_strong() and so on. For these cases, class is classified at sleep entrance rather than the synchronization initialization code. Which would extremely reduce false alarms. 2. Remove the dept associated instance in each page struct for tracking dependencies by PG_locked and PG_writeback thanks to the 1. work above. 3. Introduce CONFIG_dept_AGGRESIVE_TIMEOUT_WAIT to suppress reports that waits with timeout set are involved, for those who don't like verbose reporting. 4. Add a mechanism to refill the internal memory pools on running out so that dept could keep working as long as free memory is available in the system. 5. Re-enable tracking hashed-waitqueue wait. That's going to no longer generate false positives because class is classified at sleep entrance rather than the waitqueue initailization. 6. Refactor to make it easier to port onto each new version of the kernel. 7. Apply dept to dma fence. 8. Do trivial optimizaitions. Changes from v5: 1. Use just pr_warn_once() rather than WARN_ONCE() on the lack of internal resources because WARN_*() printing stacktrace is too much for informing the lack. (feedback from Ted, Hyeonggon) 2. Fix trivial bugs like missing initializing a struct before using it. 3. Assign a different class per task when handling onstack variables for waitqueue or the like. Which makes dept distinguish between onstack variables of different tasks so as to prevent false positives. (reported by Hyeonggon) 4. Make dept aware of even raw_local_irq_*() to prevent false positives. (reported by Hyeonggon) 5. Don't consider dependencies between the events that might be triggered within __schedule() and the waits that requires __schedule(), real ones. (reported by Hyeonggon) 6. Unstage the staged wait that has prepare_to_wait_event()'ed *and* yet to get to __schedule(), if we encounter __schedule() in-between for another sleep, which is possible if e.g. a mutex_lock() exists in 'condition' of ___wait_event(). 7. Turn on CONFIG_PROVE_LOCKING when CONFIG_DEPT is on, to rely on the hardirq and softirq entrance tracing to make dept more portable for now. Changes from v4: 1. Fix some bugs that produce false alarms. 2. Distinguish each syscall context from another *for arm64*. 3. Make it not warn it but just print it in case dept ring buffer gets exhausted. (feedback from Hyeonggon) 4. Explicitely describe "EXPERIMENTAL" and "dept might produce false positive reports" in Kconfig. (feedback from Ted) Changes from v3: 1. dept shouldn't create dependencies between different depths of a class that were indicated by *_lock_nested(). dept normally doesn't but it does once another lock class comes in. So fixed it. (feedback from Hyeonggon) 2. dept considered a wait as a real wait once getting to __schedule() even if it has been set to TASK_RUNNING by wake up sources in advance. Fixed it so that dept doesn't consider the case as a real wait. (feedback from Jan Kara) 3. Stop tracking dependencies with a map once the event associated with the map has been handled. dept will start to work with the map again, on the next sleep. Changes from v2: 1. Disable dept on bit_wait_table[] in sched/wait_bit.c reporting a lot of false positives, which is my fault. Wait/event for bit_wait_table[] should've been tagged in a higher layer for better work, which is a future work. (feedback from Jan Kara) 2. Disable dept on crypto_larval's completion to prevent a false positive. Changes from v1: 1. Fix coding style and typo. (feedback from Steven) 2. Distinguish each work context from another in workqueue. 3. Skip checking lock acquisition with nest_lock, which is about correct lock usage that should be checked by lockdep. Changes from RFC(v0): 1. Prevent adding a wait tag at prepare_to_wait() but __schedule(). (feedback from Linus and Matthew) 2. Use try version at lockdep_acquire_cpus_lock() annotation. 3. Distinguish each syscall context from another. Byungchul Park (41): dept: implement DEPT(DEPendency Tracker) dept: add single event dependency tracker APIs dept: add lock dependency tracker APIs dept: tie to lockdep and IRQ tracing dept: add proc knobs to show stats and dependency graph dept: distinguish each kernel context from another dept: distinguish each work from another dept: add a mechanism to refill the internal memory pools on running out dept: record the latest one out of consecutive waits of the same class dept: apply sdt_might_sleep_{start,end}() to wait_for_completion()/complete() dept: apply sdt_might_sleep_{start,end}() to swait dept: apply sdt_might_sleep_{start,end}() to waitqueue wait dept: apply sdt_might_sleep_{start,end}() to hashed-waitqueue wait dept: apply sdt_might_sleep_{start,end}() to dma fence dept: track timeout waits separately with a new Kconfig dept: apply timeout consideration to wait_for_completion()/complete() dept: apply timeout consideration to swait dept: apply timeout consideration to waitqueue wait dept: apply timeout consideration to hashed-waitqueue wait dept: apply timeout consideration to dma fence wait dept: make dept able to work with an external wgen dept: track PG_locked with dept dept: print staged wait's stacktrace on report locking/lockdep: prevent various lockdep assertions when lockdep_off()'ed dept: add documents for dept cpu/hotplug: use a weaker annotation in AP thread dept: assign dept map to mmu notifier invalidation synchronization dept: assign unique dept_key to each distinct dma fence caller dept: make dept aware of lockdep_set_lock_cmp_fn() annotation dept: make dept stop from working on debug_locks_off() dept: assign unique dept_key to each distinct wait_for_completion() caller completion, dept: introduce init_completion_dmap() API dept: introduce a new type of dependency tracking between multi event sites dept: add module support for struct dept_event_site and dept_event_site_dep dept: introduce event_site() to disable event tracking if it's recoverable dept: implement a basic unit test for dept dept: call dept_hardirqs_off() in local_irq_*() regardless of irq state dept: introduce APIs to set page usage and use subclasses_evt for the usage dept: track PG_writeback with dept SUNRPC: relocate struct rcu_head to the first field of struct rpc_xprt mm: percpu: increase PERCPU_DYNAMIC_SIZE_SHIFT on DEPT and large PAGE_SIZE Yunseong Kim (1): rcu/update: fix same dept key collision between various types of RCU Documentation/dev-tools/dept.rst | 778 ++++++ Documentation/dev-tools/dept_api.rst | 125 + drivers/dma-buf/dma-fence.c | 23 +- include/asm-generic/vmlinux.lds.h | 13 +- include/linux/completion.h | 124 +- include/linux/dept.h | 402 +++ include/linux/dept_ldt.h | 78 + include/linux/dept_sdt.h | 68 + include/linux/dept_unit_test.h | 67 + include/linux/dma-fence.h | 74 +- include/linux/hardirq.h | 3 + include/linux/irq-entry-common.h | 4 + include/linux/irqflags.h | 21 +- include/linux/local_lock_internal.h | 1 + include/linux/lockdep.h | 105 +- include/linux/lockdep_types.h | 3 + include/linux/mm_types.h | 4 + include/linux/mmu_notifier.h | 26 + include/linux/module.h | 5 + include/linux/mutex.h | 1 + include/linux/page-flags.h | 217 +- include/linux/pagemap.h | 37 +- include/linux/percpu-rwsem.h | 2 +- include/linux/percpu.h | 4 + include/linux/rcupdate_wait.h | 13 +- include/linux/rtmutex.h | 1 + include/linux/rwlock_types.h | 1 + include/linux/rwsem.h | 1 + include/linux/sched.h | 118 + include/linux/seqlock.h | 2 +- include/linux/spinlock_types_raw.h | 3 + include/linux/srcu.h | 2 +- include/linux/sunrpc/xprt.h | 9 +- include/linux/swait.h | 3 + include/linux/wait.h | 3 + include/linux/wait_bit.h | 3 + init/init_task.c | 2 + init/main.c | 2 + kernel/Makefile | 1 + kernel/cpu.c | 2 +- kernel/dependency/Makefile | 5 + kernel/dependency/dept.c | 3499 ++++++++++++++++++++++++++ kernel/dependency/dept_hash.h | 10 + kernel/dependency/dept_internal.h | 314 +++ kernel/dependency/dept_object.h | 13 + kernel/dependency/dept_proc.c | 94 + kernel/dependency/dept_unit_test.c | 173 ++ kernel/exit.c | 1 + kernel/fork.c | 2 + kernel/locking/lockdep.c | 33 + kernel/module/main.c | 19 + kernel/rcu/rcu.h | 1 + kernel/rcu/update.c | 5 +- kernel/sched/completion.c | 62 +- kernel/sched/core.c | 9 + kernel/workqueue.c | 3 + lib/Kconfig.debug | 48 + lib/debug_locks.c | 2 + lib/locking-selftest.c | 2 + mm/filemap.c | 38 + mm/mm_init.c | 3 + mm/mmu_notifier.c | 31 +- rust/helpers/completion.c | 5 + 63 files changed, 6602 insertions(+), 121 deletions(-) create mode 100644 Documentation/dev-tools/dept.rst create mode 100644 Documentation/dev-tools/dept_api.rst create mode 100644 include/linux/dept.h create mode 100644 include/linux/dept_ldt.h create mode 100644 include/linux/dept_sdt.h create mode 100644 include/linux/dept_unit_test.h create mode 100644 kernel/dependency/Makefile create mode 100644 kernel/dependency/dept.c create mode 100644 kernel/dependency/dept_hash.h create mode 100644 kernel/dependency/dept_internal.h create mode 100644 kernel/dependency/dept_object.h create mode 100644 kernel/dependency/dept_proc.c create mode 100644 kernel/dependency/dept_unit_test.c base-commit: 43dfc13ca972988e620a6edb72956981b75ab6b0 -- 2.17.1

1 month

Unlocking Wordplay: A Guide to the Connections Game

by profound.cheetah.kect＠hidingmail.net

In a world brimming with complex video games and immersive online experiences, sometimes the most satisfying entertainment comes from a simple yet brilliant word puzzle. The Connections Game, a daily online brain-teaser, offers just that – a delightful challenge that tests your vocabulary, logic, and lateral thinking. If you’re looking for a fresh way to engage your mind and expand your word association skills, then stepping into the world of Connections Game is a fantastic choice. https://connectionsgamefree.com What is Connections Game? At its heart, Connections is a game about finding hidden relationships between words. Each day, you're presented with 16 seemingly disparate words. Your task is to group these words into four sets of four, with each set sharing a common thread or category. The categories can be anything from "Types of Fruit" to "Words that Rhyme with 'Blue'" or even more abstract connections that require a bit of outside-the-box thinking. The beauty of the game lies in its simplicity and the sheer satisfaction of uncovering those clever links. You can experience it firsthand at Connections Game. The Gameplay Unpacked When you open the game, you'll see all 16 words laid out before you. To play, you simply click on four words you believe belong together. Once you’ve selected your quartet, you hit the "Submit" button. Correct Guess: If your four words form a valid category, they will disappear, and the category will be revealed. You'll then move on to the remaining words. Incorrect Guess: If your guess is wrong, the words will remain on the board, and you'll lose one of your four allowed mistakes. That's right – you only get four incorrect attempts before the game ends! This adds a delicious layer of pressure and strategic thinking. The categories are color-coded, ranging from "Yellow" (easiest) to "Purple" (most difficult/obscure). Often, the trickiest part is recognizing "red herrings" – words that seem to fit into multiple categories, making you second-guess your initial assumptions. Tips for Success To truly master the Connections Game, here are a few friendly tips: Read All the Words First: Before clicking anything, take a moment to scan all 16 words. Look for obvious groupings first. Are there any four words that immediately jump out as being related? Look for Obvious Categories: Sometimes, one or two categories will be relatively straightforward. Tackling these first can clear up the board and make the remaining words easier to analyze. Consider Different Meanings: Many words have multiple meanings. Don't get stuck on just one interpretation. For example, "bat" could refer to a flying mammal or a piece of sports equipment. Think About Wordplay and Sounds: Categories aren't always about literal definitions. They can involve synonyms, antonyms, rhyming words, or even words that form a phrase when combined. Utilize Your Mistakes Wisely: Remember, you only have four chances. If you’re unsure, it’s often better to hold off on a guess until you have a stronger conviction. Sometimes, eliminating other categories can clarify ambiguous words. Don't Be Afraid to Rearrange: Mentally (or even physically, if you're playing on a device that allows it) rearrange the words. Seeing them in a different order can sometimes spark new connections. Conclusion The Connections Game is more than just a pastime; it's a daily brain workout that's both challenging and incredibly rewarding. It encourages you to think critically, expand your vocabulary, and see the intricate relationships between words. Whether you're a seasoned wordsmith or just looking for a fun new way to pass the time, give it a try – you might just find your new favorite daily ritual! You can access the game daily at Connections Game.

1 month

[PATCH] dma-buf: Split sgl by largest page-aligned chunk

by David Hu

Currently, `fill_sg_entry()` splits the scatterlist using `UINT_MAX`. This creates a non-page-aligned DMA length (`0xFFFFFFFF`) for the first entry, resulting in non-page-aligned DMA addresses for all subsequent entries. While the underlying IOMMU mapping may be contiguous, hardware DMA engines often require explicit address alignment (e.g., page, cacheline, or storage sector boundaries). Passing unaligned addresses and lengths can cause explicit failures in DMA descriptor creation or silent data corruption if lower unaligned bits are truncated. Fix this by splitting the scatterlist by the largest possible page aligned chunk within `UINT_MAX` (`ALIGN_DOWN(UINT_MAX, PAGE_SIZE)`). This ensures all scatterlist DMA addresses and lengths remain page aligned and satisfy hardware constraints. Page-aligned entries allow the system to cleanly chunk payloads into PCIe MaxPayloadSize (MPS) (e.g., 128 bytes, 256 bytes, 512 bytes). As a result, this may help reduce TLP fragmentation in P2P transfers and alleviate potential congestion within a logical PCIe switch partition, especially when Relaxed Ordering is not possible due to hardware constraints. Reported-by: sashiko-bot <sashiko-bot(a)kernel.org> Closes: https://lore.kernel.org/all/20260609165431.778061F00893@smtp.kernel.org/ Fixes: 3aa31a8bb11e ("dma-buf: provide phys_vec to scatter-gather mapping routine") Cc: stable(a)vger.kernel.org Signed-off-by: David Hu <xuehaohu(a)google.com> --- drivers/dma-buf/dma-buf-mapping.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/drivers/dma-buf/dma-buf-mapping.c b/drivers/dma-buf/dma-buf-mapping.c index 794acff2546a..f2bde38fdb1f 100644 --- a/drivers/dma-buf/dma-buf-mapping.c +++ b/drivers/dma-buf/dma-buf-mapping.c @@ -5,6 +5,9 @@ */ #include <linux/dma-buf-mapping.h> #include <linux/dma-resv.h> +#include <linux/align.h> + +#define MAX_ENT_SZ ALIGN_DOWN(UINT_MAX, PAGE_SIZE) static struct scatterlist *fill_sg_entry(struct scatterlist *sgl, size_t length, dma_addr_t addr) @@ -12,9 +15,9 @@ static struct scatterlist *fill_sg_entry(struct scatterlist *sgl, size_t length, unsigned int len, nents; int i; - nents = DIV_ROUND_UP(length, UINT_MAX); + nents = DIV_ROUND_UP(length, MAX_ENT_SZ); for (i = 0; i < nents; i++) { - len = min_t(size_t, length, UINT_MAX); + len = min_t(size_t, length, MAX_ENT_SZ); length -= len; /* * DMABUF abuses scatterlist to create a scatterlist @@ -24,7 +27,7 @@ static struct scatterlist *fill_sg_entry(struct scatterlist *sgl, size_t length, * does not require the CPU list for mapping or unmapping. */ sg_set_page(sgl, NULL, 0, 0); - sg_dma_address(sgl) = addr + (dma_addr_t)i * UINT_MAX; + sg_dma_address(sgl) = addr + (dma_addr_t)i * MAX_ENT_SZ; sg_dma_len(sgl) = len; sgl = sg_next(sgl); } @@ -41,14 +44,14 @@ static unsigned int calc_sg_nents(struct dma_iova_state *state, if (!state || !dma_use_iova(state)) { for (i = 0; i < nr_ranges; i++) - nents += DIV_ROUND_UP(phys_vec[i].len, UINT_MAX); + nents += DIV_ROUND_UP(phys_vec[i].len, MAX_ENT_SZ); } else { /* * In IOVA case, there is only one SG entry which spans * for whole IOVA address space, but we need to make sure * that it fits sg->length, maybe we need more. */ - nents = DIV_ROUND_UP(size, UINT_MAX); + nents = DIV_ROUND_UP(size, MAX_ENT_SZ); } return nents; -- 2.55.0.rc0.738.g0c8ab3ebcc-goog

1 month, 1 week

[PATCH] dma_buf: change unsigned int and int types into size_t

by Shahyan Soltani

The num_fences, count, i, and j variables in dma_fence_dedup_array() and __dma_fence_unwrap_merge() have inconsistent integer types, mixing both unsigned int and int. Use type size_t consistently for these instead, and update the return type of dma_fence_dedup_array() accordingly. Signed-off-by: Shahyan Soltani <shahyan.soltani(a)amd.com> Suggested-by: Philipp Stanner <phasta(a)mailbox.org> --- The rest of the subsystems (dma_resv_reserve_fences, drm_exec, drm_gpuvm, xe, nouveau, etc) uses "unsigned int" for num_fences, for example the amdgpu caller in amdgpu_userq_fence.c. drivers/dma-buf/dma-fence-unwrap.c | 8 ++++---- include/linux/dma-fence-unwrap.h | 6 ++++-- 2 files changed, 8 insertions(+), 6 deletions(-) diff --git a/drivers/dma-buf/dma-fence-unwrap.c b/drivers/dma-buf/dma-fence-unwrap.c index 53bb40e70b27..65e87d263c3a 100644 --- a/drivers/dma-buf/dma-fence-unwrap.c +++ b/drivers/dma-buf/dma-fence-unwrap.c @@ -93,9 +93,9 @@ static int fence_cmp(const void *_a, const void *_b) * * Return: Number of unique fences remaining in the array. */ -int dma_fence_dedup_array(struct dma_fence **fences, int num_fences) +size_t dma_fence_dedup_array(struct dma_fence **fences, size_t num_fences) { - int i, j; + size_t i, j; sort(fences, num_fences, sizeof(*fences), fence_cmp, NULL); @@ -115,14 +115,14 @@ int dma_fence_dedup_array(struct dma_fence **fences, int num_fences) EXPORT_SYMBOL_GPL(dma_fence_dedup_array); /* Implementation for the dma_fence_merge() marco, don't use directly */ -struct dma_fence *__dma_fence_unwrap_merge(unsigned int num_fences, +struct dma_fence *__dma_fence_unwrap_merge(size_t num_fences, struct dma_fence **fences, struct dma_fence_unwrap *iter) { struct dma_fence *tmp, *unsignaled = NULL, **array; struct dma_fence_array *result; ktime_t timestamp; - int i, count; + size_t i, count; count = 0; timestamp = ns_to_ktime(0); diff --git a/include/linux/dma-fence-unwrap.h b/include/linux/dma-fence-unwrap.h index 62df222fe0f1..7bfacdf79de2 100644 --- a/include/linux/dma-fence-unwrap.h +++ b/include/linux/dma-fence-unwrap.h @@ -8,6 +8,8 @@ #ifndef __LINUX_DMA_FENCE_UNWRAP_H #define __LINUX_DMA_FENCE_UNWRAP_H +#include <linux/types.h> + struct dma_fence; /** @@ -48,11 +50,11 @@ struct dma_fence *dma_fence_unwrap_next(struct dma_fence_unwrap *cursor); for (fence = dma_fence_unwrap_first(head, cursor); fence; \ fence = dma_fence_unwrap_next(cursor)) -struct dma_fence *__dma_fence_unwrap_merge(unsigned int num_fences, +struct dma_fence *__dma_fence_unwrap_merge(size_t num_fences, struct dma_fence **fences, struct dma_fence_unwrap *cursors); -int dma_fence_dedup_array(struct dma_fence **array, int num_fences); +size_t dma_fence_dedup_array(struct dma_fence **array, size_t num_fences); /** * dma_fence_unwrap_merge - unwrap and merge fences -- 2.54.0

1 month, 1 week

dma_fence cleanup/rework

by Christian König

In a recent discussion with Philip and Danilo the question came up what was already tried and never finished to cleanup the dma_fence framework. So here are the different ideas I came with but never fully finished, with the patches itself modernized and rebased on top of drm-misc-next. The main goal of those changes is to make it easier to implement dma_fence backends and don't enforce unnecessary constrains on implementations. As first step the locking around the dma_fence_ops.signaled callback is made consistent by removing the dma_fence_is_signaled_locked() function. This was mostly used by backends itself, but if polling the HW is desired the backends can call their own functions for this directly without going through the dma-fence layer. XE actually seems to be the only driver which make use of that for a bit more handling. For all other cases testing the signaled flag should be enough. Then forcefully calling dma_fence_signaled() is removed from the dma-fence layer and moved into the backend implementations. This allows the backend implementations to cleanup after they have signaled the fence. Such cleanup can include removing now signaled fences from lists, dropping references, starting work etc.... Especially nouveau seems to have some really messy workaround because of that involving the DMA_FENCE_FLAG_USER_BITS and installing callbacks because the reference to the context couldn't be dropped directly after signaling. This can now be cleaned up as far as I can see. In the long term this should also allow reworking the error handling, e.g. removing dma_fence_set_error() and instead giving the error as mandatory parameter to dma_fence_signal(). Then the last piece is dropping calling enable_signaling callback with the dma_fence lock held. This makes it possible for backends to acquire locks which are semantically ordered outside of the dma_fence lock. This is necessary to allows using the dma_fence inline lock in more cases, previously backends used some common external lock for their dma_fences to for example make it possible remove fences from linked lists. Please comment and review, Christian.

1 month, 1 week

[PATCH v2] drm/sched: Protect entity->last_scheduled with spinlock

by Philipp Stanner

The entity->last_scheduled field has always been set and read with special RCU functions in addition to memory barriers. There is no obvious reason for that, since the entity lock is available and taken at all places that evaluate the last_scheduled field. The only exception is drm_sched_entity_error(), which is not performance critical in any way. Improve robustness, readability and maintainability by replacing RCU and barriers with the lock. As a preparational step, while at it, also guard spsc_queue_pop() with the lock, since spsc_queue is deprecated and supposed to be replaced with a locked list. Signed-off-by: Philipp Stanner <phasta(a)kernel.org> --- Changes since v1: - Add a helper variable to drop the last_scheduled reference without the entity lock being held; just to be more robust. - Write additional comment to detail the WRITE_ONCE(). --- drivers/gpu/drm/scheduler/sched_entity.c | 58 +++++++++++++----------- include/drm/gpu_scheduler.h | 9 ++-- 2 files changed, 35 insertions(+), 32 deletions(-) diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c index c51101ec70c1..12fd695c6d46 100644 --- a/drivers/gpu/drm/scheduler/sched_entity.c +++ b/drivers/gpu/drm/scheduler/sched_entity.c @@ -135,7 +135,6 @@ int drm_sched_entity_init(struct drm_sched_entity *entity, entity->num_sched_list = num_sched_list; entity->sched_list = num_sched_list > 1 ? sched_list : NULL; entity->rq = &sched_list[0]->rq; - RCU_INIT_POINTER(entity->last_scheduled, NULL); RB_CLEAR_NODE(&entity->rb_tree_node); init_completion(&entity->entity_idle); @@ -201,10 +200,10 @@ int drm_sched_entity_error(struct drm_sched_entity *entity) struct dma_fence *fence; int r; - rcu_read_lock(); - fence = rcu_dereference(entity->last_scheduled); + spin_lock(&entity->lock); + fence = entity->last_scheduled; r = fence ? fence->error : 0; - rcu_read_unlock(); + spin_unlock(&entity->lock); return r; } @@ -288,8 +287,10 @@ void drm_sched_entity_kill(struct drm_sched_entity *entity) wait_for_completion(&entity->entity_idle); /* The entity is guaranteed to not be used by the scheduler */ - prev = rcu_dereference_check(entity->last_scheduled, true); + spin_lock(&entity->lock); + prev = entity->last_scheduled; dma_fence_get(prev); + spin_unlock(&entity->lock); while ((job = drm_sched_entity_queue_pop(entity))) { struct drm_sched_fence *s_fence = job->s_fence; @@ -381,8 +382,12 @@ void drm_sched_entity_fini(struct drm_sched_entity *entity) entity->dependency = NULL; } - dma_fence_put(rcu_dereference_check(entity->last_scheduled, true)); - RCU_INIT_POINTER(entity->last_scheduled, NULL); + dma_fence_put(entity->last_scheduled); + /* + * Normally all users should be gone now, but since drm_sched has + * experienced many layering violations in the past, better be safe. + */ + WRITE_ONCE(entity->last_scheduled, NULL); drm_sched_entity_stats_put(entity->stats); } EXPORT_SYMBOL(drm_sched_entity_fini); @@ -507,6 +512,10 @@ drm_sched_job_dependency(struct drm_sched_job *job, struct drm_sched_job *drm_sched_entity_pop_job(struct drm_sched_entity *entity) { + /* Helper to avoid dropping the reference while the entity lock is held, + * just to have some more robustness. + */ + struct dma_fence *prev_last_scheduled; struct drm_sched_job *sched_job; sched_job = drm_sched_entity_queue_peek(entity); @@ -523,19 +532,20 @@ struct drm_sched_job *drm_sched_entity_pop_job(struct drm_sched_entity *entity) if (entity->guilty && atomic_read(entity->guilty)) dma_fence_set_error(&sched_job->s_fence->finished, -ECANCELED); - dma_fence_put(rcu_dereference_check(entity->last_scheduled, true)); - rcu_assign_pointer(entity->last_scheduled, - dma_fence_get(&sched_job->s_fence->finished)); + spin_lock(&entity->lock); + prev_last_scheduled = entity->last_scheduled; + entity->last_scheduled = dma_fence_get(&sched_job->s_fence->finished); - /* - * If the queue is empty we allow drm_sched_entity_select_rq() to - * locklessly access ->last_scheduled. This only works if we set the - * pointer before we dequeue and if we a write barrier here. + /* A recent rework required taking the spinlock above. Since spsc_queue + * is scheduled for removal as per the DRM-TODO-list, we access it here + * locked already to prepare for that cleanup. + * + * TODO: Fully replace spsc_queue with a locked (h)list. */ - smp_wmb(); - spsc_queue_pop(&entity->job_queue); + spin_unlock(&entity->lock); + dma_fence_put(prev_last_scheduled); drm_sched_rq_pop_entity(entity); /* Jobs and entities might have different lifecycles. Since we're @@ -561,21 +571,15 @@ void drm_sched_entity_select_rq(struct drm_sched_entity *entity) if (spsc_queue_count(&entity->job_queue)) return; - /* - * Only when the queue is empty are we guaranteed that - * drm_sched_run_job_work() cannot change entity->last_scheduled. To - * enforce ordering we need a read barrier here. See - * drm_sched_entity_pop_job() for the other side. - */ - smp_rmb(); - - fence = rcu_dereference_check(entity->last_scheduled, true); + spin_lock(&entity->lock); + fence = entity->last_scheduled; /* stay on the same engine if the previous job hasn't finished */ - if (fence && !dma_fence_is_signaled(fence)) + if (fence && !dma_fence_is_signaled(fence)) { + spin_unlock(&entity->lock); return; + } - spin_lock(&entity->lock); sched = drm_sched_pick_best(entity->sched_list, entity->num_sched_list); rq = sched ? &sched->rq : NULL; if (rq != entity->rq) { diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h index d61c19e78182..176ff1f936cd 100644 --- a/include/drm/gpu_scheduler.h +++ b/include/drm/gpu_scheduler.h @@ -100,7 +100,8 @@ struct drm_sched_entity { * @lock: * * Lock protecting the run-queue (@rq) to which this entity belongs, - * @priority and the list of schedulers (@sched_list, @num_sched_list). + * @priority, @last_scheduled and the list of schedulers (@sched_list, + * @num_sched_list). */ spinlock_t lock; @@ -202,11 +203,9 @@ struct drm_sched_entity { /** * @last_scheduled: * - * Points to the finished fence of the last scheduled job. Only written - * by drm_sched_entity_pop_job(). Can be accessed locklessly from - * drm_sched_job_arm() if the queue is empty. + * Points to the finished fence of the last scheduled job. */ - struct dma_fence __rcu *last_scheduled; + struct dma_fence *last_scheduled; /** * @last_user: last group leader pushing a job into the entity. -- 2.54.0

1 month, 1 week

Wordle Unlimited Game Guide for Endless Word Puzzle Fun

by thoughtless.stork.wxrl＠hidingmail.net

Introduction to Wordle Unlimited Experience Wordle Unlimited is an online word puzzle game that expands the classic word guessing concept into an endless format. Instead of waiting for a daily puzzle, players can enjoy continuous gameplay with unlimited attempts and unlimited rounds. This format makes it appealing for players who enjoy vocabulary challenges, logic thinking, and casual gaming without time restrictions. https://wordleunlimitedgame.org/ The main objective remains simple. Players try to guess a hidden five letter word within a limited number of attempts. After each guess, feedback is provided through color indicators that help narrow down the correct answer. This simple design combined with endless replay value makes Wordle Unlimited highly engaging for both beginners and experienced puzzle players. How Wordle Unlimited Gameplay Works Wordle Unlimited follows a straightforward set of rules that are easy to understand. Each round begins with a hidden word that players must discover. Players enter a five letter word as a guess, and the system responds with color coded hints. Green indicates a correct letter in the correct position. Yellow indicates a correct letter in the wrong position. Gray indicates a letter that is not part of the hidden word. These feedback signals guide players toward the correct answer step by step. Unlike traditional daily word puzzles, Wordle Unlimited allows continuous play without waiting periods. Players can restart instantly after finishing a round, making it suitable for practice, entertainment, or improving vocabulary skills. This unlimited structure also allows experimentation with different guessing strategies. Key Features of Wordle Unlimited One of the most important features of Wordle Unlimited is unlimited gameplay. Players are not restricted to a single puzzle per day, which increases engagement and learning opportunities. This feature is especially useful for users who enjoy repetitive practice or competitive improvement. Another key feature is accessibility. The game runs directly in a web browser, meaning no installation is required. It works on desktop computers, tablets, and mobile devices, making it convenient for users in different environments. Wordle Unlimited also maintains a simple interface. There are no complicated menus or distractions. The focus remains entirely on word solving. This minimal design helps players concentrate and improves the overall puzzle solving experience. Additionally, the game supports learning and vocabulary development. Players are exposed to different word patterns and letter combinations, which can help improve language skills over time. Effective Strategies for Winning Wordle Unlimited A strong strategy in Wordle Unlimited begins with choosing a good starting word. Many players select words that contain common vowels and frequently used consonants. This approach increases the chance of identifying correct letters early in the game. Another effective strategy is to avoid repeating incorrect letters. Once a letter is marked as gray, it is usually best to exclude it from future guesses. This helps narrow down possibilities more efficiently. Players also benefit from analyzing letter placement carefully. When a letter is marked yellow, it should be repositioned in the next guess. This process of elimination is essential for solving puzzles in fewer attempts. It is also helpful to think in word patterns rather than random guesses. English words often follow predictable structures, and recognizing these patterns can significantly improve success rates. Finally, patience plays an important role. Rushing guesses can lead to repeated mistakes. Taking time to evaluate feedback from each attempt leads to more accurate solutions. Benefits of Playing Wordle Unlimited Regularly Playing Wordle Unlimited regularly offers several cognitive benefits. One major advantage is vocabulary improvement. Players are exposed to a wide range of words, which helps expand language knowledge over time. Another benefit is mental exercise. Word puzzle games stimulate logical thinking, pattern recognition, and memory recall. These skills are useful in both academic and professional contexts. Wordle Unlimited also provides stress relief for many players. The simple structure and short gameplay sessions make it a relaxing activity that can be enjoyed during breaks or free time. In addition, the unlimited nature of the game allows continuous practice. This is especially beneficial for players who want to improve performance or challenge themselves with faster solving times. Social interaction is another indirect benefit. Many players enjoy sharing results or competing with friends, which adds a fun and competitive element to the experience. Why Wordle Unlimited Remains Popular The popularity of Wordle Unlimited comes from its balance of simplicity and challenge. It does not require advanced gaming skills, yet it still offers a satisfying mental challenge. This combination makes it accessible to a wide audience. The unlimited format also contributes to its popularity. Players are no longer restricted by daily limits, which means they can engage with the game whenever they want. This flexibility aligns well with modern digital habits. Another reason for its popularity is its quick gameplay loop. Each round can be completed in a short time, making it ideal for casual entertainment. Despite its simplicity, the game continues to offer new challenges with every hidden word. Conclusion on Wordle Unlimited Experience Wordle Unlimited delivers a simple yet highly engaging word puzzle experience that appeals to players of all ages. With unlimited gameplay, easy rules, and strong cognitive benefits, it stands out as an effective and enjoyable word game.

1 month, 1 week

[PATCH] dma-buf/test: add KUnit case for dma_fence_dedup_array() empty input

by Baineng Shou

Add a KUnit case verifying that dma_fence_dedup_array() returns 0, not 1, when called with num_fences == 0. This locks down the contract documented in the kernel-doc and prevents a regression of commit 77a9298741f8 ("dma-fence: Make dma_fence_dedup_array() robust against 0-count input"). Suggested-by: Christian König <christian.koenig(a)amd.com> Signed-off-by: Baineng Shou <shoubaineng(a)gmail.com> --- drivers/dma-buf/st-dma-fence-unwrap.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/dma-buf/st-dma-fence-unwrap.c b/drivers/dma-buf/st-dma-fence-unwrap.c index 4e7ee25372ba..72dea6091d58 100644 --- a/drivers/dma-buf/st-dma-fence-unwrap.c +++ b/drivers/dma-buf/st-dma-fence-unwrap.c @@ -370,6 +370,15 @@ static void test_unwrap_merge_seqno(struct kunit *test) dma_fence_put(f1); } +static void test_dedup_empty(struct kunit *test) +{ + struct dma_fence *fence[1] = { NULL }; + int ret; + + ret = dma_fence_dedup_array(fence, 0); + KUNIT_EXPECT_EQ(test, ret, 0); +} + static void test_unwrap_merge_order(struct kunit *test) { struct dma_fence *fence, *f1, *f2, *a1, *a2, *c1, *c2; @@ -595,6 +604,7 @@ static struct kunit_case dma_fence_unwrap_cases[] = { KUNIT_CASE(test_unwrap_merge_order), KUNIT_CASE(test_unwrap_merge_complex), KUNIT_CASE(test_unwrap_merge_complex_seqno), + KUNIT_CASE(test_dedup_empty), {} }; -- 2.34.1

1 month, 1 week

Bouncing Your Way Through Geometry: What Makes Jump Games So Addictive

by clinical.condor.xuhe＠hidingmail.net

https://geometrydash-pc.com/ Geometry-based jump games have become a phenomenon in casual gaming, and for good reason. There's something deeply satisfying about timing a perfect jump, watching your character soar through geometric obstacles, and finally reaching that "just one more level" feeling at 11 PM on a Tuesday. If you've never experienced this particular brand of digital frustration and joy, let me walk you through what makes these games tick—and why your reflexes might thank you (or curse you) for giving them a try. The Beautiful Simplicity of Jumping Through Shapes At their core, geometry jump games strip gaming down to its essence: move, jump, survive, repeat. Take Geometry Dash as our primary example. The concept sounds almost comically simple—you control a geometric shape (typically a square) and must navigate it through an obstacle course of spikes, platforms, and other hazards, all synchronized to music. That's it. No complex storylines, no resource management, no unnecessary mechanics getting in the way. The genius lies in how this simplicity becomes a foundation for incredible complexity. Early levels ease you in with gentle slopes and straightforward obstacles. But as you progress, the game introduces new mechanics: your shape might transform into a ship that flies and falls with different physics, or a cube that can jump at precise intervals, or a ball that rolls with its own momentum. Each transformation changes how you perceive and interact with the space around you, keeping the experience fresh despite the unchanging core mechanic. What really hooks players is the relationship between gameplay and sound design. In these games, your jumps, movements, and even collisions sync with the background music. This isn't just eye candy—it creates a rhythm that your brain naturally wants to follow. Successfully nailing a sequence of jumps that align with the beat feels almost musical, like you're dancing through geometry rather than simply fighting your way through it. How the Experience Actually Works When you first launch a geometry jump game, you'll notice the visual style leans toward minimalism. Bright colors contrast against dark backgrounds. Obstacles are clearly defined geometric shapes. There's no confusion about what you can and can't touch—a spike is a spike, a platform is a platform. This clarity is crucial because the game demands precision, and it delivers that demand through an uncluttered visual language. The difficulty curve in these games teaches an important lesson about game design. Early levels act as a tutorial without ever pausing to explain things. You learn through doing. You discover that holding the jump button longer makes you jump higher (in certain modes). You realize that some obstacles require split-second timing while others reward patience. The game respects your intelligence enough not to spell everything out, yet supports you enough that progress feels achievable. Progression in these games works differently than traditional level-based structures. Levels often exceed three or four minutes of continuous gameplay. A single mistake near the end sends you back to the beginning. This sounds punishing, and initially it is, but it creates something interesting: players develop the ability to stay focused under pressure. You learn to accept failure as part of the process. That 47th attempt doesn't feel like torture—it feels like you're getting closer. Practical Tips for New Players If you're thinking about diving into a geometry jump experience, here are some things that will make your journey more enjoyable. First, play with sound on (with headphones if possible). The audio design isn't decorative—it's genuinely part of the game. Your brain will start anticipating jumps based on musical cues. Second, accept that you'll fail repeatedly. A lot. This isn't a flaw in game design; it's the entire point. Each failure teaches you something about timing, positioning, or physics. Instead of thinking "I'm bad at this," think "I'm learning." The shift in mindset makes an enormous difference in how frustrating or fun the experience becomes. Third, take breaks when you're stuck. Walk away for 20 minutes, come back fresh, and you'll often breeze through what seemed impossible before. Your muscle memory and spatial reasoning improve even when you're not actively playing—your brain keeps processing those patterns. Finally, don't compare your progress to others immediately. These games feature leaderboards and difficulty ratings that can feel intimidating. Focus on completing the built-in levels first and getting comfortable with the mechanics. Once you're ready, the community has created custom levels at every difficulty level imaginable. The Lasting Appeal What keeps people returning to geometry jump games isn't just the challenge—it's the feeling of growth. You watch your own improvement in real-time. That level that seemed impossible yesterday becomes a warm-up today. Your fingers develop instinctive knowledge of the physics without your brain consciously calculating them. These games also offer something increasingly rare in modern entertainment: they don't demand your attention span be fragmented. They ask for focus, dedication, and patience in exchange for genuine achievement. In a world of endless notifications and distractions, there's something refreshing about a game that simply wants you to jump through some shapes to the beat of good music. Whether you're a casual gamer looking for something satisfying or someone seeking a new challenge, geometry jump games offer an experience that's easy to understand but genuinely difficult to master. And honestly, that's exactly what makes them worth your time.

1 month, 1 week

Geometry Dash Lite: A Rhythm-Based Odyssey in the Palm of Your Hand

by 77nannette＠web-library.net

Ever found yourself yearning for a game that’s easy to pick up but incredibly challenging to master? A game that tests your reflexes, your rhythm, and your patience, all while delivering a surprisingly addictive experience? Look no further than geometry dash lite. This free-to-play mobile sensation, a trimmed-down version of the full Geometry Dash game, offers a fantastic entry point into a world of pulsing electronic music, geometric obstacles, and an almost zen-like focus on timing. Whether you're a seasoned gamer or just looking for a fun way to pass the time, Geometry Dash Lite provides an exhilarating ride. https://geometrylitepc.com/ The Rhythmic Heartbeat: What is Geometry Dash Lite? At its core, Geometry Dash Lite is a rhythm-based platformer. You control a small, customizable icon (usually a square, but you can unlock others) that automatically moves forward through a series of levels. Your sole objective is to navigate these levels, avoiding an onslaught of spikes, sawblades, and other cleverly designed traps, all perfectly synced to an energetic soundtrack. The game's beauty lies in its simplicity: tap to jump. That's it. But within this simple mechanic lies a world of nuanced timing, precise execution, and a surprising amount of strategic thinking. The "Lite" version of the game offers a selection of levels from the full Geometry Dash experience, allowing players to get a taste of what the full game has to offer without any initial commitment. It's a perfect sampler, showcasing the core mechanics, the diverse level design, and the infectious music that defines the series. For those curious to explore further or even play on their PC, you can find more information about Geometry Dash Lite at Geometry Dash Lite Gameplay: A Symphony of Taps and Jumps The gameplay loop of Geometry Dash Lite is incredibly straightforward, yet it offers a satisfying and often frustrating challenge. Your Icon: Your main character is a small geometric shape that continuously moves forward. Its movement speed is constant within a given segment of a level. The Obstacles: Levels are littered with various obstacles, primarily spikes and sawblades, designed to instantly destroy your icon upon contact. The Tap to Jump: Your only control is to tap the screen. A single tap initiates a small jump. Holding down your finger allows for a longer jump. This simple interaction is the key to navigating the complex layouts. Portals and Gravity: As you progress, you'll encounter various portals that change your icon's behavior. These can include: Gravity Portals: These flip your icon's gravity, making it move on the ceiling instead of the floor, or vice versa. Ship Portals: Your icon transforms into a ship, allowing you to fly freely by holding down your finger to ascend and releasing to descend. This introduces a whole new dimension of control. Ball Portals: Your icon becomes a ball, which rolls and can stick to surfaces when you tap, creating unique platforming opportunities. UFO Portals: These transform your icon into a UFO, allowing for a "flappy bird" like tapping mechanic to ascend. Wave Portals: Your icon becomes a wave, moving diagonally up and down with taps, requiring very precise timing. Music Synchronization: Every jump, every obstacle, and every portal change is meticulously synchronized with the background music. This is not just an aesthetic choice; it’s a crucial gameplay element. Learning the rhythm of each level is as important as memorizing its layout. Practice Mode: One of the most player-friendly features is the practice mode. In this mode, you can place checkpoints anywhere in the level, allowing you to repeatedly attempt difficult sections without having to restart from the beginning. This is invaluable for learning and improving. Attempts Counter: A relentless counter at the top of the screen tracks how many attempts it takes you to complete a level. This often fuels a competitive spirit and a desire to achieve fewer attempts. Tips for Conquering the Geometric Gauntlet While Geometry Dash Lite can feel overwhelming at first, a few key strategies can significantly improve your experience and help you conquer even the most daunting levels. 1. Start Slow and Steady: Don't jump into the hardest level immediately. Begin with the introductory levels to get a feel for the controls, the different portal mechanics, and the rhythm. "Stereo Madness" is a classic starting point. 2. Embrace Practice Mode: This cannot be stressed enough. When you hit a wall, switch to practice mode. Break down the level into smaller, manageable segments. Practice each difficult section until you can consistently clear it. 3. Listen to the Music: The music isn't just background noise; it's your guide. Pay close attention to the beats, the drops, and the changes in tempo. Often, the timing of your jumps will align perfectly with the musical cues. 4. Memorization is Key: While reflexes are important, Geometry Dash Lite is also a memory game. As you repeatedly play a level, you'll start to internalize the layout and the sequence of obstacles. 5. Identify Patterns: Many levels feature recurring patterns of obstacles. Once you recognize these patterns, you can apply the same strategy to clear them each time they appear. 6. Don't Get Frustrated (Easily): This game will test your patience. You will die countless times on the same obstacle. Take a break if you feel yourself getting angry. Come back with a fresh perspective. Sometimes, a short break is all it takes to clear a section you were stuck on. 7. Watch Others Play: If you're truly stuck, watching videos of experienced players completing the level can provide valuable insights into optimal timing and strategies. 8. Customize Your Icon: While purely aesthetic, customizing your icon can make the experience feel more personal and enjoyable. Unlock new colors and shapes as you progress. 9. Focus on Small Victories: Don't aim to complete the entire level in one go initially. Celebrate clearing a new section, reaching a further point, or successfully navigating a tricky portal sequence. Conclusion: A Rewarding Test of Skill and Rhythm Geometry Dash Lite is more than just a simple mobile game; it's a testament to the power of straightforward mechanics combined with clever design. It offers a rewarding challenge that, while demanding, never feels truly unfair. The satisfaction of finally completing a difficult level, feeling your fingers dance across the screen in perfect sync with the music, is an experience few other games can replicate. So, if you're looking for a game that will push your reflexes and your rhythm to their limits, all while delivering a surprisingly addictive and fun experience, dive into the world of Geometry Dash Lite. You might just find your next obsession.

1 month, 1 week

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