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From: Qi Zheng In-Reply-To: <20260714101740.1270419-1-usama.arif@linux.dev> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: 8A098A0004 X-Rspam-User: X-Stat-Signature: uqbu7apps8ar8jrnnfntq4xp8kd5dd3m X-Rspamd-Server: rspam03 X-HE-Tag: 1784026408-172065 X-HE-Meta: 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 KqSwBBnh 31LDg/Wja4kStaURaww9y3u48DGJDHuCeTGggUfma7IXz8+GaObVvOsAChNOeBYTTEXfg6dBkHSzh1c9RF1GRdvPXwpERMbdJYXLYgNyD8QNY9eQa0jyOZqApB+jnNio4xz9hXA8tqnEQQ7lD/KWOI1QTRsRFv3zImLEaVPdy2AnYkOegLSfO+jcQYmhKS42xwfLg7Wim04/rwyQlzjx1r5bU20P/rQ+1O1sC62ChJfixKAC1eG8RdZsI+9jaFvCcxR6YowV2yqQJhODHRwqurnYV9w== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 7/14/26 6:17 PM, Usama Arif wrote: > On Tue, 14 Jul 2026 10:09:26 +0800 Qi Zheng wrote: > >> Hi Usama, >> >> On 7/13/26 11:34 PM, Usama Arif wrote: >>> >>> >>> On 13/07/2026 14:12, Qi Zheng wrote: >>>> Hi Usama, >>>> >>>> On 6/9/26 8:30 PM, Usama Arif wrote: >>>>> The super_block shrinker is registered with SHRINKER_MEMCG_AWARE because its >>>>> dentry and inode LRUs are memcg-aware (via list_lru). But the optional >>>>> ->nr_cached_objects() hooks that the shrinker also drives are not memcg-aware: >>>>> btrfs extent maps and xfs inode reclaim operate on filesystem-global >>>>> state, and shmem's unused-huge shrinker walks a per-superblock shrinklist. >>>>> None of them filter by sc->memcg. >>>> >>>> This makes sense for now, but how should we handle this if these >>>> shrinkers are made memcg-aware in the future? >>>> >>>> I've recently been working on making the shmem huge shrinker >>>> memcg-aware, but noticed my changes broke after rebasing onto the latest >>>> tree, which led me to this patch. >>>> >>>> As for the shmem huge shrinker, I can work around this limitation by >>>> making it a separate shrinker. But this feels more like an overall >>>> design decision, effectively meaning that all nr_cached_objects are >>>> precluded from being memcg-aware. >>>> >>>> Thanks, >>>> Qi >>>> >>> >>> >>> Hi Qi, >>> >>> Thanks for raising this. I think the alternative is what I mentioned in >>> https://lore.kernel.org/all/cfdb8620-ea55-4226-98bf-d006820e6270@linux.dev/ >>> move this down to the fs own callbacks instead of here. Would that >>> be better? >> >> Yes, I think this is a better approach. >> >> Later on, shrinkers that are converted to be memcg-aware can lift this >> restriction themselves. >> >> Thanks, >> Qi > > Thanks Qi, I have sent a patch to push it down to filesystems in [1]. > No functional change inteneded in there. You would have to rebase your > patch on top of that one and remove my code in shmem specifically. Thanks! I will rebase my patch once your patch is merged into linux-next. > > [1] https://lore.kernel.org/all/20260714101454.1202449-1-usama.arif@linux.dev/ > >> >>> >>> Thanks, >>> Usama >> >>