From: Peter Zijlstra <peterz@infradead.org> To: Byungchul Park <byungchul.park@lge.com> Cc: mingo@kernel.org, tglx@linutronix.de, walken@google.com, boqun.feng@gmail.com, kirill@shutemov.name, linux-kernel@vger.kernel.org, linux-mm@kvack.org, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org, willy@infradead.org, npiggin@gmail.com, kernel-team@lge.com Subject: Re: [PATCH v6 05/15] lockdep: Implement crossrelease feature Date: Wed, 19 Apr 2017 16:25:03 +0200 [thread overview] Message-ID: <20170419142503.rqsrgjlc7ump7ijb@hirez.programming.kicks-ass.net> (raw) In-Reply-To: <1489479542-27030-6-git-send-email-byungchul.park@lge.com> On Tue, Mar 14, 2017 at 05:18:52PM +0900, Byungchul Park wrote: > +struct hist_lock { > + /* > + * Each work of workqueue might run in a different context, > + * thanks to concurrency support of workqueue. So we have to > + * distinguish each work to avoid false positive. > + */ > + unsigned int work_id; > }; > @@ -1749,6 +1749,14 @@ struct task_struct { > struct held_lock held_locks[MAX_LOCK_DEPTH]; > gfp_t lockdep_reclaim_gfp; > #endif > +#ifdef CONFIG_LOCKDEP_CROSSRELEASE > +#define MAX_XHLOCKS_NR 64UL > + struct hist_lock *xhlocks; /* Crossrelease history locks */ > + unsigned int xhlock_idx; > + unsigned int xhlock_idx_soft; /* For backing up at softirq entry */ > + unsigned int xhlock_idx_hard; /* For backing up at hardirq entry */ > + unsigned int work_id; > +#endif > #ifdef CONFIG_UBSAN > unsigned int in_ubsan; > #endif > +/* > + * Crossrelease needs to distinguish each work of workqueues. > + * Caller is supposed to be a worker. > + */ > +void crossrelease_work_start(void) > +{ > + if (current->xhlocks) > + current->work_id++; > +} > +/* > + * Only access local task's data, so irq disable is only required. > + */ > +static int same_context_xhlock(struct hist_lock *xhlock) > +{ > + struct task_struct *curr = current; > + > + /* In the case of hardirq context */ > + if (curr->hardirq_context) { > + if (xhlock->hlock.irq_context & 2) /* 2: bitmask for hardirq */ > + return 1; > + /* In the case of softriq context */ > + } else if (curr->softirq_context) { > + if (xhlock->hlock.irq_context & 1) /* 1: bitmask for softirq */ > + return 1; > + /* In the case of process context */ > + } else { > + if (xhlock->work_id == curr->work_id) > + return 1; > + } > + return 0; > +} I still don't like work_id; it doesn't have anything to do with workqueues per se, other than the fact that they end up using it. It's a history generation id; touching it completely invalidates our history. Workqueues need this because they run independent work from the same context. But the same is true for other sites. Last time I suggested lockdep_assert_empty() to denote all suck places (and note we already have lockdep_sys_exit() that hooks into the return to user path).
WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org> To: Byungchul Park <byungchul.park@lge.com> Cc: mingo@kernel.org, tglx@linutronix.de, walken@google.com, boqun.feng@gmail.com, kirill@shutemov.name, linux-kernel@vger.kernel.org, linux-mm@kvack.org, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org, willy@infradead.org, npiggin@gmail.com, kernel-team@lge.com Subject: Re: [PATCH v6 05/15] lockdep: Implement crossrelease feature Date: Wed, 19 Apr 2017 16:25:03 +0200 [thread overview] Message-ID: <20170419142503.rqsrgjlc7ump7ijb@hirez.programming.kicks-ass.net> (raw) In-Reply-To: <1489479542-27030-6-git-send-email-byungchul.park@lge.com> On Tue, Mar 14, 2017 at 05:18:52PM +0900, Byungchul Park wrote: > +struct hist_lock { > + /* > + * Each work of workqueue might run in a different context, > + * thanks to concurrency support of workqueue. So we have to > + * distinguish each work to avoid false positive. > + */ > + unsigned int work_id; > }; > @@ -1749,6 +1749,14 @@ struct task_struct { > struct held_lock held_locks[MAX_LOCK_DEPTH]; > gfp_t lockdep_reclaim_gfp; > #endif > +#ifdef CONFIG_LOCKDEP_CROSSRELEASE > +#define MAX_XHLOCKS_NR 64UL > + struct hist_lock *xhlocks; /* Crossrelease history locks */ > + unsigned int xhlock_idx; > + unsigned int xhlock_idx_soft; /* For backing up at softirq entry */ > + unsigned int xhlock_idx_hard; /* For backing up at hardirq entry */ > + unsigned int work_id; > +#endif > #ifdef CONFIG_UBSAN > unsigned int in_ubsan; > #endif > +/* > + * Crossrelease needs to distinguish each work of workqueues. > + * Caller is supposed to be a worker. > + */ > +void crossrelease_work_start(void) > +{ > + if (current->xhlocks) > + current->work_id++; > +} > +/* > + * Only access local task's data, so irq disable is only required. > + */ > +static int same_context_xhlock(struct hist_lock *xhlock) > +{ > + struct task_struct *curr = current; > + > + /* In the case of hardirq context */ > + if (curr->hardirq_context) { > + if (xhlock->hlock.irq_context & 2) /* 2: bitmask for hardirq */ > + return 1; > + /* In the case of softriq context */ > + } else if (curr->softirq_context) { > + if (xhlock->hlock.irq_context & 1) /* 1: bitmask for softirq */ > + return 1; > + /* In the case of process context */ > + } else { > + if (xhlock->work_id == curr->work_id) > + return 1; > + } > + return 0; > +} I still don't like work_id; it doesn't have anything to do with workqueues per se, other than the fact that they end up using it. It's a history generation id; touching it completely invalidates our history. Workqueues need this because they run independent work from the same context. But the same is true for other sites. Last time I suggested lockdep_assert_empty() to denote all suck places (and note we already have lockdep_sys_exit() that hooks into the return to user path). -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2017-04-19 14:25 UTC|newest] Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-03-14 8:18 [PATCH v6 00/15] lockdep: Implement crossrelease feature Byungchul Park 2017-03-14 8:18 ` Byungchul Park 2017-03-14 8:18 ` [PATCH v6 01/15] lockdep: Refactor lookup_chain_cache() Byungchul Park 2017-03-14 8:18 ` Byungchul Park 2017-03-14 8:18 ` [PATCH v6 02/15] lockdep: Add a function building a chain between two classes Byungchul Park 2017-03-14 8:18 ` Byungchul Park 2017-03-14 8:18 ` [PATCH v6 03/15] lockdep: Change the meaning of check_prev_add()'s return value Byungchul Park 2017-03-14 8:18 ` Byungchul Park 2017-03-14 8:18 ` [PATCH v6 04/15] lockdep: Make check_prev_add() able to handle external stack_trace Byungchul Park 2017-03-14 8:18 ` Byungchul Park 2017-03-14 8:18 ` [PATCH v6 05/15] lockdep: Implement crossrelease feature Byungchul Park 2017-03-14 8:18 ` Byungchul Park 2017-04-19 14:25 ` Peter Zijlstra [this message] 2017-04-19 14:25 ` Peter Zijlstra 2017-04-24 5:11 ` Byungchul Park 2017-04-24 5:11 ` Byungchul Park 2017-04-24 10:17 ` Peter Zijlstra 2017-04-24 10:17 ` Peter Zijlstra 2017-04-25 5:40 ` Byungchul Park 2017-04-25 5:40 ` Byungchul Park 2017-05-16 14:18 ` Peter Zijlstra 2017-05-16 14:18 ` Peter Zijlstra 2017-05-18 6:22 ` Byungchul Park 2017-05-18 6:22 ` Byungchul Park 2017-04-19 15:08 ` Peter Zijlstra 2017-04-19 15:08 ` Peter Zijlstra 2017-04-24 4:36 ` Byungchul Park 2017-04-24 4:36 ` Byungchul Park 2017-04-19 17:19 ` Peter Zijlstra 2017-04-19 17:19 ` Peter Zijlstra 2017-04-24 3:04 ` Byungchul Park 2017-04-24 3:04 ` Byungchul Park 2017-04-24 9:30 ` Peter Zijlstra 2017-04-24 9:30 ` Peter Zijlstra 2017-04-25 6:59 ` Byungchul Park 2017-04-25 6:59 ` Byungchul Park 2017-04-19 17:20 ` Peter Zijlstra 2017-04-19 17:20 ` Peter Zijlstra 2017-04-24 3:13 ` Byungchul Park 2017-04-24 3:13 ` Byungchul Park 2017-05-19 8:07 ` Byungchul Park 2017-05-19 8:07 ` Byungchul Park 2017-05-19 10:30 ` Peter Zijlstra 2017-05-19 10:30 ` Peter Zijlstra 2017-05-19 10:56 ` Byungchul Park 2017-05-19 10:56 ` Byungchul Park 2017-03-14 8:18 ` [PATCH v6 06/15] lockdep: Handle non(or multi)-acquisition of a crosslock Byungchul Park 2017-03-14 8:18 ` Byungchul Park 2017-03-14 8:18 ` [PATCH v6 07/15] lockdep: Avoid adding redundant direct links of crosslocks Byungchul Park 2017-03-14 8:18 ` Byungchul Park 2017-03-14 8:18 ` [PATCH v6 08/15] lockdep: Fix incorrect condition to print bug msgs for MAX_LOCKDEP_CHAIN_HLOCKS Byungchul Park 2017-03-14 8:18 ` Byungchul Park 2017-03-14 8:18 ` [PATCH v6 09/15] lockdep: Make print_circular_bug() aware of crossrelease Byungchul Park 2017-03-14 8:18 ` Byungchul Park 2017-03-14 8:18 ` [PATCH v6 10/15] lockdep: Apply crossrelease to completions Byungchul Park 2017-03-14 8:18 ` Byungchul Park 2017-03-14 8:18 ` [PATCH v6 11/15] pagemap.h: Remove trailing white space Byungchul Park 2017-03-14 8:18 ` Byungchul Park 2017-03-14 8:18 ` [PATCH v6 12/15] lockdep: Apply crossrelease to PG_locked locks Byungchul Park 2017-03-14 8:18 ` Byungchul Park 2017-03-14 8:19 ` [PATCH v6 13/15] lockdep: Apply lock_acquire(release) on __Set(__Clear)PageLocked Byungchul Park 2017-03-14 8:19 ` Byungchul Park 2017-03-14 8:19 ` [PATCH v6 14/15] lockdep: Move data of CONFIG_LOCKDEP_PAGELOCK from page to page_ext Byungchul Park 2017-03-14 8:19 ` Byungchul Park 2017-03-14 8:19 ` [PATCH v6 15/15] lockdep: Crossrelease feature documentation Byungchul Park 2017-03-14 8:19 ` Byungchul Park
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