Re: [PATCH v3 2/2] virtio_balloon: replace oom notifier with shrinker
From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Date: 2018-08-06 13:28:59
On 2018/08/06 21:44, Wang, Wei W wrote:
On Monday, August 6, 2018 6:29 PM, Tetsuo Handa wrote:quoted
On 2018/08/06 18:56, Wei Wang wrote:quoted
On 08/03/2018 08:11 PM, Tetsuo Handa wrote:quoted
On 2018/08/03 17:32, Wei Wang wrote:quoted
+static int virtio_balloon_register_shrinker(struct virtio_balloon +*vb) { + vb->shrinker.scan_objects = virtio_balloon_shrinker_scan; + vb->shrinker.count_objects = virtio_balloon_shrinker_count; + vb->shrinker.batch = 0; + vb->shrinker.seeks = DEFAULT_SEEKS;Why flags field is not set? If vb is allocated by kmalloc(GFP_KERNEL) and is nowhere zero-cleared, KASAN would complain it.Could you point where in the code that would complain it? I only see two shrinker flags (NUMA_AWARE and MEMCG_AWARE), andthey seem not related to that. Where is vb->shrinker.flags initialized?Is that mandatory to be initialized?
Of course. ;-)
I find it's not initialized in most shrinkers (e.g. zs_register_shrinker, huge_zero_page_shrinker).
Because most shrinkers are "statically initialized (which means that unspecified fields are implicitly zero-cleared)" or "dynamically allocated with __GFP_ZERO or zero-cleared using memset() (which means that all fields are once zero-cleared)". And if you once zero-clear vb at allocation time, you will get a bonus that calling unregister_shrinker() without corresponding register_shrinker() is safe (which will simplify initialization failure path). _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization