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b=BOO8mr+KXgLD5vOFopSdSqQmPVPMqQixeSWn9ammwAxW10qXGrLRzOvCc53rBbFDk yiEtT172Lvfllx1jQJbtEjdxQutXpK6P5tm3ZJf6JoQfIxrWABiH0ajqRfoxCbThvl aE5KqK0Rxn2+YMJeqJYgX5QcUJ9yqm5tb5PVCXy1y5q/7rkHJjMw0sg3ypOCCIeEs8 YAKECPLIOb8v97UHaVEzoVqZW2gyo/WOuVlOp22Ay9cWqwx0OHMUd9lz7YW3JnaD2J 9d9txktlBFl/XJMSg4sa1GvdZ2t7TYO4PIomKmOweW3jeX/+qZCyD6GQxn+1QHQL2d /xEaFbsOx7UIg== Message-ID: Date: Thu, 14 May 2026 18:00:06 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [linux-next:master] [mm, slab] 298cdbf5f7: will-it-scale.per_process_ops 6.3% regression Content-Language: en-US From: "Vlastimil Babka (SUSE)" To: kernel test robot , "Harry Yoo (Oracle)" Cc: oe-lkp@lists.linux.dev, lkp@intel.com, Hao Li , linux-mm@kvack.org References: <202605112204.9382cecf-lkp@intel.com> <90bf195e-45fb-423c-b686-49be9cadbd11@kernel.org> In-Reply-To: <90bf195e-45fb-423c-b686-49be9cadbd11@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 04D1F40012 X-Stat-Signature: md9oskt3ysrba85dcaj6xkbztxpjxnrf X-HE-Tag: 1778774410-783471 X-HE-Meta: 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 sYa+jKQ/ lvMzk+/aROv3pBUCYzAXFJSU8AdsWQ0tbS67wbqxRAt/bIaWFSsr1KnuhoLyWINgLKyfXzNKXp8W2aFTO3pA3maBkP2KHII64aVzgGx5XXaGLugEChrmimFrnre8/bH2PFB/1pOP09U+SfUj4iwev1chp5uyGNDMAFcXFjDfnYNYD1kKesfHubO0J8SMZZjRn6MAKyFFq6o4kQq474u0V3lW/xf+vZBl9xNfYEinP1lDAxY38t37cXzHTGXoJUdoDZqzW6zcEuvkTaXNAm1aG68H7HA44bMOXL7i+hVWUSIl7IK9HaJpjvEexZ1g4iVErVHe7t71gvmBR/+Q= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 5/14/26 16:45, Vlastimil Babka (SUSE) wrote: > On 5/11/26 16:45, kernel test robot wrote: >> >> >> Hello, >> >> kernel test robot noticed a 6.3% regression of will-it-scale.per_process_ops on: > > Yay for an optimization that was supposed to have no tradeoffs :) Does this help? I don't expect much, but perhaps... - list_empty(&pc.slabs) is no longer unlikely when it can likely have a slab where we returned part of the freelist - let's ignore s->min_partial when returning slabs, we just pulled them from the list, it's unlikely there are too many free slabs, and unlikely we have free slabs to return. Maybe it will reduce the page alloc/frees and the code is simpler >From 761946747d53b880855ac1e795ae0627be416c3e Mon Sep 17 00:00:00 2001 From: "Vlastimil Babka (SUSE)" Date: Thu, 14 May 2026 17:55:31 +0200 Subject: [PATCH] mm, slab: simplify __refill_objects_node --- mm/slub.c | 12 +----------- 1 file changed, 1 insertion(+), 11 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index 5d867349912b..0cc6c88f11e3 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -7187,26 +7187,16 @@ __refill_objects_node(struct kmem_cache *s, void **p, gfp_t gfp, unsigned int mi break; } - if (unlikely(!list_empty(&pc.slabs))) { + if (!list_empty(&pc.slabs)) { spin_lock_irqsave(&n->list_lock, flags); list_for_each_entry_safe(slab, slab2, &pc.slabs, slab_list) { - if (unlikely(!slab->inuse && n->nr_partial >= s->min_partial)) - continue; - list_del(&slab->slab_list); add_partial(n, slab, ADD_TO_HEAD); } spin_unlock_irqrestore(&n->list_lock, flags); - - /* any slabs left are completely free and for discard */ - list_for_each_entry_safe(slab, slab2, &pc.slabs, slab_list) { - - list_del(&slab->slab_list); - discard_slab(s, slab); - } } return refilled; -- 2.54.0