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[109.81.92.77]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-37189849cdbsm3025635f8f.28.2024.08.16.00.19.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 16 Aug 2024 00:19:59 -0700 (PDT) Date: Fri, 16 Aug 2024 09:19:58 +0200 From: Michal Hocko To: Matthew Wilcox Cc: Roman Gushchin , Shakeel Butt , Andrew Morton , Johannes Weiner , Muchun Song , "T . J . Mercier" , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Meta kernel team , cgroups@vger.kernel.org Subject: Re: [PATCH v2] memcg: replace memcg ID idr with xarray Message-ID: References: <20240815155402.3630804-1-shakeel.butt@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: D1FD218001E X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: umu3booxbgpq1zrrfr7f95d3pj65tgo5 X-HE-Tag: 1723792801-844171 X-HE-Meta: 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 zhYVIXq2 3MqF0Ghf27uc6AUeqzOYe2PYTJCEvHbytIfgaJ6VK2faIdFCwIuNPuFNJ1nAUf05gYFyac6rXKW1N1yn9dHspVpTF5dHwf/Ig3vQFb1vxuQVsQqf8NIBEKquQFs7+bytLDXRQX6kcnTleb8uxZgnJmudpfgX0ctQ3Zuq62eaIKTWySWOIqPKNUyWukYYVbDnvJALjblYgcx0/5Zo4wqzMAn3iS5QkiDM/pq5Opw/UNMLguW0dZSFn/L+spM8aBXXzGaTU6P0lOJVjUqf7hBVR2g8rGR6fW4QjiP8q X-Bogosity: Ham, tests=bogofilter, spamicity=0.000001, 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 15-08-24 22:16:27, Matthew Wilcox wrote: > On Thu, Aug 15, 2024 at 07:31:43PM +0000, Roman Gushchin wrote: > > There is another subtle change here: xa_alloc() returns -EBUSY in the case > > of the address space exhaustion, while the old code returned -ENOSPC. > > It's unlikely a big practical problem. > > I decided that EBUSY was the right errno for this situation; > > #define EBUSY 16 /* Device or resource busy */ > #define ENOSPC 28 /* No space left on device */ > > ENOSPC seemed wrong; the device isn't out of space. The thing is that this is observable by userspace - mkdir would return a different and potentially unexpected errno. We can try and see whether anybody complains or just translate the error. -- Michal Hocko SUSE Labs