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).
next prev parent reply other threads:[~2017-04-19 14:25 UTC|newest]
Thread overview: 33+ 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 ` [PATCH v6 01/15] lockdep: Refactor lookup_chain_cache() 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 ` [PATCH v6 03/15] lockdep: Change the meaning of check_prev_add()'s return value 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 ` [PATCH v6 05/15] lockdep: Implement crossrelease feature Byungchul Park
2017-04-19 14:25 ` Peter Zijlstra [this message]
2017-04-24 5:11 ` Byungchul Park
2017-04-24 10:17 ` Peter Zijlstra
2017-04-25 5:40 ` Byungchul Park
2017-05-16 14:18 ` Peter Zijlstra
2017-05-18 6:22 ` Byungchul Park
2017-04-19 15:08 ` Peter Zijlstra
2017-04-24 4:36 ` Byungchul Park
2017-04-19 17:19 ` Peter Zijlstra
2017-04-24 3:04 ` Byungchul Park
2017-04-24 9:30 ` Peter Zijlstra
2017-04-25 6:59 ` Byungchul Park
2017-04-19 17:20 ` Peter Zijlstra
2017-04-24 3:13 ` Byungchul Park
2017-05-19 8:07 ` Byungchul Park
2017-05-19 10:30 ` Peter Zijlstra
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 ` [PATCH v6 07/15] lockdep: Avoid adding redundant direct links of crosslocks 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 ` [PATCH v6 09/15] lockdep: Make print_circular_bug() aware of crossrelease Byungchul Park
2017-03-14 8:18 ` [PATCH v6 10/15] lockdep: Apply crossrelease to completions Byungchul Park
2017-03-14 8:18 ` [PATCH v6 11/15] pagemap.h: Remove trailing white space Byungchul Park
2017-03-14 8:18 ` [PATCH v6 12/15] lockdep: Apply crossrelease to PG_locked locks 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 ` [PATCH v6 14/15] lockdep: Move data of CONFIG_LOCKDEP_PAGELOCK from page to page_ext Byungchul Park
2017-03-14 8:19 ` [PATCH v6 15/15] lockdep: Crossrelease feature documentation Byungchul Park
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