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From: "Alex Bennée" <alex.bennee@linaro.org>
To: Emilio Cota <cota@braap.org>
Cc: qemu-devel@nongnu.org, "Paolo Bonzini" <pbonzini@redhat.com>,
	"Philippe Mathieu-Daudé" <philmd@linaro.org>,
	"Richard Henderson" <richard.henderson@linaro.org>
Subject: Re: [PATCH v2 4/5] util/qht: use striped locks under TSAN
Date: Wed, 11 Jan 2023 13:03:53 +0000	[thread overview]
Message-ID: <87v8ldkyt0.fsf@linaro.org> (raw)
In-Reply-To: <Y74h2RC+8J63Nzqj@cota-l14>


Emilio Cota <cota@braap.org> writes:

> On Tue, Jan 10, 2023 at 20:58:01 +0000, Alex Bennée wrote:
>> Emilio Cota <cota@braap.org> writes:
> (snip)
>> > +static inline void qht_do_if_first_in_stripe(const struct qht_map *map,
>> > +                                             struct qht_bucket *b,
>> > +                                             void (*func)(QemuSpin *spin))
>> > +{
>> > +#ifdef CONFIG_TSAN
>> > +    unsigned long bucket_idx = b - map->buckets;
>> > +    bool is_first_in_stripe = (bucket_idx >> QHT_TSAN_BUCKET_LOCKS_BITS) == 0;
>> > +    if (is_first_in_stripe) {
>> > +        unsigned long lock_idx = bucket_idx & (QHT_TSAN_BUCKET_LOCKS - 1);
>> > +        func(&map->tsan_bucket_locks[lock_idx]);
>> 
>> Hmm I ran into an issue with:
>> 
>>      ../util/qht.c:286:10: error: incompatible pointer types passing
>> 'const struct qht_tsan_lock *' to parameter of type 'QemuSpin *'
>> (aka 'struct QemuSpin *') [-Werror,-Wincompatible-pointer-types]
>
> Gaah, sorry. I didn't notice this because of unrelated noise due
> to having to configure with --disable-werror. Fixed now by removing
> a bunch of const's and also using .lock.
>
>> > +static inline void qht_bucket_lock_destroy(const struct qht_map *map,
>> > +                                           struct qht_bucket *b)
>> > +{
>> > +    qht_do_if_first_in_stripe(map, b, qemu_spin_destroy);
>> > +}
>> 
>> Who is meant to be calling this?
>
> Should have been removed in v2; fixed now.
>
> I've uploaded the v3 series to https://github.com/cota/qemu/tree/tsan-v3
>
> Please let me know if you want me to also mail it to the list.

Please do and then I can be sure I'm upto date when I rebuild the PR.

> Thanks,
>
> 		Emilio


-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro


  reply	other threads:[~2023-01-11 13:05 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-09 22:49 [PATCH v2 0/5] tsan fixes Emilio Cota
2023-01-09 22:49 ` [PATCH v2 1/5] cpu: free cpu->tb_jmp_cache with RCU Emilio Cota
2023-01-09 22:49 ` [PATCH v2 2/5] util/qht: add missing atomic_set(hashes[i]) Emilio Cota
2023-01-10  9:08   ` Alex Bennée
2023-01-09 22:49 ` [PATCH v2 3/5] thread: de-const qemu_spin_destroy Emilio Cota
2023-01-10  9:09   ` Alex Bennée
2023-01-09 22:49 ` [PATCH v2 4/5] util/qht: use striped locks under TSAN Emilio Cota
2023-01-10 20:58   ` Alex Bennée
2023-01-11  2:41     ` Emilio Cota
2023-01-11 13:03       ` Alex Bennée [this message]
2023-01-09 22:49 ` [PATCH v2 5/5] plugins: make qemu_plugin_user_exit's locking order consistent with fork_start's Emilio Cota
2023-01-10  7:31   ` Philippe Mathieu-Daudé
2023-01-10 12:55 ` [PATCH v2 0/5] tsan fixes Alex Bennée
2023-01-10 15:50   ` Richard Henderson

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