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b=OxWk/8aR8YyKI0IIfNPcT4oBKAxRHkK1+iD2RM21iDHXttBrR1xZWBs1bxljrhvOr OVQNmvsw34sGqurJl9ObDE98Dp3jHjBPbgBBKMfki9/5PmN/FqsoO6onTPSk/Y0ipq dCYGajcSSKfIKix9f5sM4Zo6YXJ+rgfcAVOrJ49I= Date: Thu, 17 Jul 2025 15:46:49 -0700 From: Andrew Morton To: Davidlohr Bueso Cc: Roman Gushchin , mhocko@kernel.org, hannes@cmpxchg.org, shakeel.butt@linux.dev, yosryahmed@google.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 4/4] mm: introduce per-node proactive reclaim interface Message-Id: <20250717154649.796cca17cf422783a79b4e5a@linux-foundation.org> In-Reply-To: <20250717162637.xz77hsj2byamivgm@offworld> References: <20250623185851.830632-1-dave@stgolabs.net> <20250623185851.830632-5-dave@stgolabs.net> <87qzyfr0u6.fsf@linux.dev> <20250717162637.xz77hsj2byamivgm@offworld> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Stat-Signature: go14iqhpf1phsue9rgpnmsu65xbtqgcc X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 993CA40007 X-Rspam-User: X-HE-Tag: 1752792411-286565 X-HE-Meta: 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 KRfshfc8 Z50NdnwxBAp6er1n9MdbVwbwMrSSYMwzQ/q16sdkpLxJR3rjGpL2ofCsADxX5P+Jfdqby7tLYNgALuGrvgktEamQgR8nzJRI6Ho7ilyKb6NXRsP8EEhHISOl3WO4S3hYovZPHL5mtZh03P8IsiphLJ8VkT3ehZ9OBahyZDazP/Jxu9Hpfbw18SXBNaKf0jmcY+meddCqV+/PQJOKxDrntZ0RPl8Gsxjo+ZQQLl9Q9DH3wO1Sn9OwHQ/6Nv22lAuNy0/qBCO7sz88aJO2QyZELu6tje8zCSg/51bM1bnB2JmhqrV3hXpySIGY3EgbATNAH+Esmca1BGJnnbRiJ3FOMR8x4IvAV/eCkIvR+FJ24VqwxsmSgal/zAepDEvu1JDbMaaCvvZdB16wgpwCxUQkJLj3ZB4RAI23WPjWmGXKZ4URUeUvKuJz28Yy6O3ZAHKxYJPaqozjajrW77dEK2E+F/YLodw== 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 Thu, 17 Jul 2025 09:26:37 -0700 Davidlohr Bueso wrote: > >> + if (test_and_set_bit_lock(PGDAT_RECLAIM_LOCKED, > >> + &pgdat->flags)) > >> + return -EAGAIN; > > > >Isn't EBUSY a better choice here? > >At least to distinguish between no reclaimable memory left and > >somebody else is abusing the same interface cases. > > Yes, I agree. From: Andrew Morton Subject: mm-introduce-per-node-proactive-reclaim-interface-fix Date: Thu Jul 17 03:44:14 PM PDT 2025 user_proactive_reclaim(): return -EBUSY on PGDAT_RECLAIM_LOCKED contention, per Roman Cc: Davidlohr Bueso Cc: Johannes Weiner Cc: Michal Hocko Cc: Roman Gushchin Cc: Shakeel Butt Cc: Yosry Ahmed Signed-off-by: Andrew Morton --- mm/vmscan.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/vmscan.c~mm-introduce-per-node-proactive-reclaim-interface-fix +++ a/mm/vmscan.c @@ -7818,7 +7818,7 @@ int user_proactive_reclaim(char *buf, if (test_and_set_bit_lock(PGDAT_RECLAIM_LOCKED, &pgdat->flags)) - return -EAGAIN; + return -EBUSY; reclaimed = __node_reclaim(pgdat, gfp_mask, batch_size, &sc); _