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Subject: Re: [PATCH v4] mm: cma: support sysfs
From:   Dmitry Osipenko <digetx@gmail.com>
To:     Minchan Kim <minchan@kernel.org>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        linux-mm <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>, joaodias@google.com,
        willy@infradead.org, david@redhat.com, surenb@google.com,
        John Hubbard <jhubbard@nvidia.com>,
        Nicolas Chauvet <kwizart@gmail.com>,
        "linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>
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Message-ID: <f2187cd5-505b-5274-c2a8-706a9c26aa2d@gmail.com>
Date:   Fri, 19 Mar 2021 20:44:09 +0300
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19.03.2021 20:41, Dmitry Osipenko пишет:
> 19.03.2021 20:29, Dmitry Osipenko пишет:
>> +void cma_sysfs_alloc_pages_count(struct cma *cma, size_t count)
>> +{
>> +	atomic64_add(count, &cma->nr_pages_succeeded);
>> +}
>> +
>> +void cma_sysfs_fail_pages_count(struct cma *cma, size_t count)
>> +{
>> +	atomic64_add(count, &cma->nr_pages_failed);
>> +}
> 
> The atomic looks good, but aren't CMA allocations already protected by
> the CMA core? Do we really need to worry about racing here?
> 

Although, please scratch that. I see now that these functions are called
outside of the lock.