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Peter Anvin" , Vlastimil Babka , Zi Yan , Mike Rapoport , Dave Hansen , Michal Hocko , David Hildenbrand , Andrew Morton , Thomas Gleixner , Nico Pache , Dev Jain , "Liam R . Howlett" , Jens Axboe , linux-kernel@vger.kernel.org, willy@infradead.org, linux-mm@kvack.org, x86@kernel.org, linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, "Darrick J . Wong" , mcgrof@kernel.org, gost.dev@samsung.com, hch@lst.de, Pankaj Raghav Subject: Re: [PATCH v2 2/5] huge_memory: add huge_zero_page_shrinker_(init|exit) function Message-ID: <2ir5ul6baqj7dk6uw5opwnsxuxfmobtoehyfxglnsadlrcurjs@7akcf3auqink> References: <20250707142319.319642-1-kernel@pankajraghav.com> <20250707142319.319642-3-kernel@pankajraghav.com> <762c0b08-f5a5-4e76-8203-70514de6b5c8@lucifer.local> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <762c0b08-f5a5-4e76-8203-70514de6b5c8@lucifer.local> X-Rspamd-Queue-Id: 9644D1C0013 X-Stat-Signature: dcami8uitkydboayzffjyoc9ynbcmauh X-Rspam-User: X-Rspamd-Server: rspam11 X-HE-Tag: 1752653320-82420 X-HE-Meta: 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 GBbQfTY7 kOJZLnaCr7TY7nVekYDAAi4V39RsYDzKFhA7drOu77En10sGJ46rKLySS0QJOlFk7EfNADvUc7YDi7DzMas4iF3GbXEgEo26y6sszFJjeYTuEAgjeLzKO2ep4JvP8wTSCvsPSwEvscNesVdEokrkroISVxd5jH7lOWqxmk2dzyo6k/hlpbWIb68X/Uq4Z9LfOBBdUxp4/hufzjJQDw17w6ZTxInlfAWYJLGDpOg2bKV7+x8rtGntKD4lbMY98rx3ulF/gkTDolSWkTpkPawdeKZXWYRVxnb3Ii5mw2FRDoFpVAHjLh0ID/bd22GQfVTTQJ78XAgkhT50DrNv7jnBhKPXKXiZm6QHxs62T+3ZOkC/CEqfwFymuCgVjOzlqn4hnkC/7 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Jul 15, 2025 at 03:29:08PM +0100, Lorenzo Stoakes wrote: > Nit on subject, function -> functions. > > On Mon, Jul 07, 2025 at 04:23:16PM +0200, Pankaj Raghav (Samsung) wrote: > > From: Pankaj Raghav > > > > Add huge_zero_page_shrinker_init() and huge_zero_page_shrinker_exit(). > > As shrinker will not be needed when static PMD zero page is enabled, > > these two functions can be a no-op. > > > > This is a preparation patch for static PMD zero page. No functional > > changes. > > This is nitty stuff, but I think this is a little unclear, maybe something > like: > > We will soon be determining whether to use a shrinker depending on > whether a static PMD zero page is available, therefore abstract out > shrink initialisation and teardown such that we can more easily > handle both the shrinker and static PMD zero page cases. > This looks good. I will use add this to the commit message. > > > > Signed-off-by: Pankaj Raghav > > Other than nits, this LGTM, so with those addressed: > > Reviewed-by: Lorenzo Stoakes Thanks. > > #ifdef CONFIG_SYSFS > > static ssize_t enabled_show(struct kobject *kobj, > > @@ -850,33 +868,31 @@ static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) > > > > static int __init thp_shrinker_init(void) > > { > > - huge_zero_page_shrinker = shrinker_alloc(0, "thp-zero"); > > - if (!huge_zero_page_shrinker) > > - return -ENOMEM; > > + int ret = 0; > > Kinda no point in initialising to zero, unless... > > > > > deferred_split_shrinker = shrinker_alloc(SHRINKER_NUMA_AWARE | > > SHRINKER_MEMCG_AWARE | > > SHRINKER_NONSLAB, > > "thp-deferred_split"); > > - if (!deferred_split_shrinker) { > > - shrinker_free(huge_zero_page_shrinker); > > + if (!deferred_split_shrinker) > > return -ENOMEM; > > - } > > - > > - huge_zero_page_shrinker->count_objects = shrink_huge_zero_page_count; > > - huge_zero_page_shrinker->scan_objects = shrink_huge_zero_page_scan; > > - shrinker_register(huge_zero_page_shrinker); > > > > deferred_split_shrinker->count_objects = deferred_split_count; > > deferred_split_shrinker->scan_objects = deferred_split_scan; > > shrinker_register(deferred_split_shrinker); > > > > + ret = huge_zero_page_shrinker_init(); > > + if (ret) { > > + shrinker_free(deferred_split_shrinker); > > + return ret; > > + } > > ... you change this to: > > if (ret) > shrinker_free(deferred_split_shrinker); > > return ret; > > But it's not a big deal. Maybe I'd rename ret -> err if you keep things as > they are (but don't init to 0). Sounds good. -- Pankaj