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Thu, 22 Jan 2026 08:49:15 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id +qgXCovkcWmFAwAAD6G6ig (envelope-from ); Thu, 22 Jan 2026 08:49:15 +0000 Message-ID: <1e3092b1-23df-441d-8849-84aa0632ee88@suse.cz> Date: Thu, 22 Jan 2026 09:49:14 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 18/21] slab: update overview comments Content-Language: en-US To: Harry Yoo Cc: Petr Tesarik , Christoph Lameter , David Rientjes , Roman Gushchin , Hao Li , Andrew Morton , Uladzislau Rezki , "Liam R. Howlett" , Suren Baghdasaryan , Sebastian Andrzej Siewior , Alexei Starovoitov , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev, bpf@vger.kernel.org, kasan-dev@googlegroups.com References: <20260116-sheaves-for-all-v3-0-5595cb000772@suse.cz> <20260116-sheaves-for-all-v3-18-5595cb000772@suse.cz> From: Vlastimil Babka Autocrypt: addr=vbabka@suse.cz; keydata= xsFNBFZdmxYBEADsw/SiUSjB0dM+vSh95UkgcHjzEVBlby/Fg+g42O7LAEkCYXi/vvq31JTB KxRWDHX0R2tgpFDXHnzZcQywawu8eSq0LxzxFNYMvtB7sV1pxYwej2qx9B75qW2plBs+7+YB 87tMFA+u+L4Z5xAzIimfLD5EKC56kJ1CsXlM8S/LHcmdD9Ctkn3trYDNnat0eoAcfPIP2OZ+ 9oe9IF/R28zmh0ifLXyJQQz5ofdj4bPf8ecEW0rhcqHfTD8k4yK0xxt3xW+6Exqp9n9bydiy tcSAw/TahjW6yrA+6JhSBv1v2tIm+itQc073zjSX8OFL51qQVzRFr7H2UQG33lw2QrvHRXqD Ot7ViKam7v0Ho9wEWiQOOZlHItOOXFphWb2yq3nzrKe45oWoSgkxKb97MVsQ+q2SYjJRBBH4 8qKhphADYxkIP6yut/eaj9ImvRUZZRi0DTc8xfnvHGTjKbJzC2xpFcY0DQbZzuwsIZ8OPJCc LM4S7mT25NE5kUTG/TKQCk922vRdGVMoLA7dIQrgXnRXtyT61sg8PG4wcfOnuWf8577aXP1x 6mzw3/jh3F+oSBHb/GcLC7mvWreJifUL2gEdssGfXhGWBo6zLS3qhgtwjay0Jl+kza1lo+Cv BB2T79D4WGdDuVa4eOrQ02TxqGN7G0Biz5ZLRSFzQSQwLn8fbwARAQABzSBWbGFzdGltaWwg QmFia2EgPHZiYWJrYUBzdXNlLmN6PsLBlAQTAQoAPgIbAwULCQgHAwUVCgkICwUWAgMBAAIe AQIXgBYhBKlA1DSZLC6OmRA9UCJPp+fMgqZkBQJnyBr8BQka0IFQAAoJECJPp+fMgqZkqmMQ AIbGN95ptUMUvo6aAdhxaOCHXp1DfIBuIOK/zpx8ylY4pOwu3GRe4dQ8u4XS9gaZ96Gj4bC+ jwWcSmn+TjtKW3rH1dRKopvC07tSJIGGVyw7ieV/5cbFffA8NL0ILowzVg8w1ipnz1VTkWDr 2zcfslxJsJ6vhXw5/npcY0ldeC1E8f6UUoa4eyoskd70vO0wOAoGd02ZkJoox3F5ODM0kjHu Y97VLOa3GG66lh+ZEelVZEujHfKceCw9G3PMvEzyLFbXvSOigZQMdKzQ8D/OChwqig8wFBmV QCPS4yDdmZP3oeDHRjJ9jvMUKoYODiNKsl2F+xXwyRM2qoKRqFlhCn4usVd1+wmv9iLV8nPs 2Db1ZIa49fJet3Sk3PN4bV1rAPuWvtbuTBN39Q/6MgkLTYHb84HyFKw14Rqe5YorrBLbF3rl M51Dpf6Egu1yTJDHCTEwePWug4XI11FT8lK0LNnHNpbhTCYRjX73iWOnFraJNcURld1jL1nV r/LRD+/e2gNtSTPK0Qkon6HcOBZnxRoqtazTU6YQRmGlT0v+rukj/cn5sToYibWLn+RoV1CE Qj6tApOiHBkpEsCzHGu+iDQ1WT0Idtdynst738f/uCeCMkdRu4WMZjteQaqvARFwCy3P/jpK uvzMtves5HvZw33ZwOtMCgbpce00DaET4y/UzsBNBFsZNTUBCACfQfpSsWJZyi+SHoRdVyX5 J6rI7okc4+b571a7RXD5UhS9dlVRVVAtrU9ANSLqPTQKGVxHrqD39XSw8hxK61pw8p90pg4G /N3iuWEvyt+t0SxDDkClnGsDyRhlUyEWYFEoBrrCizbmahOUwqkJbNMfzj5Y7n7OIJOxNRkB IBOjPdF26dMP69BwePQao1M8Acrrex9sAHYjQGyVmReRjVEtv9iG4DoTsnIR3amKVk6si4Ea X/mrapJqSCcBUVYUFH8M7bsm4CSxier5ofy8jTEa/CfvkqpKThTMCQPNZKY7hke5qEq1CBk2 wxhX48ZrJEFf1v3NuV3OimgsF2odzieNABEBAAHCwXwEGAEKACYCGwwWIQSpQNQ0mSwujpkQ PVAiT6fnzIKmZAUCZ8gcVAUJFhTonwAKCRAiT6fnzIKmZLY8D/9uo3Ut9yi2YCuASWxr7QQZ lJCViArjymbxYB5NdOeC50/0gnhK4pgdHlE2MdwF6o34x7TPFGpjNFvycZqccSQPJ/gibwNA zx3q9vJT4Vw+YbiyS53iSBLXMweeVV1Jd9IjAoL+EqB0cbxoFXvnjkvP1foiiF5r73jCd4PR rD+GoX5BZ7AZmFYmuJYBm28STM2NA6LhT0X+2su16f/HtummENKcMwom0hNu3MBNPUOrujtW khQrWcJNAAsy4yMoJ2Lw51T/5X5Hc7jQ9da9fyqu+phqlVtn70qpPvgWy4HRhr25fCAEXZDp xG4RNmTm+pqorHOqhBkI7wA7P/nyPo7ZEc3L+ZkQ37u0nlOyrjbNUniPGxPxv1imVq8IyycG AN5FaFxtiELK22gvudghLJaDiRBhn8/AhXc642/Z/yIpizE2xG4KU4AXzb6C+o7LX/WmmsWP Ly6jamSg6tvrdo4/e87lUedEqCtrp2o1xpn5zongf6cQkaLZKQcBQnPmgHO5OG8+50u88D9I rywqgzTUhHFKKF6/9L/lYtrNcHU8Z6Y4Ju/MLUiNYkmtrGIMnkjKCiRqlRrZE/v5YFHbayRD dJKXobXTtCBYpLJM4ZYRpGZXne/FAtWNe4KbNJJqxMvrTOrnIatPj8NhBVI0RSJRsbilh6TE m6M14QORSWTLRg== In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: E1B5220006 X-Stat-Signature: 3eb5j3g7i8ed9p5qmkbtqwm6sdy731sg X-Rspam-User: X-HE-Tag: 1769071756-602119 X-HE-Meta: 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 43fwSo+M bmb/fcII6aghQpDzDhqmUAENI+Bs3CbU8eUD5d1u7KaS8EpQAavVENd643v/ekQKHzD1bGC2yuOyJXhFeGFJ3il/2VbbM1c+787wCidOdeD3NvVEkywOujOwFw0cD/L++rCJm5PVds53E+SNXH1iv3S+z6Gmn7Z7r2RMqbsVty+JUQ9tUM5+4TUgYUUPuzJHEpL9iVXzOr2bJbWfORCZvmiMD/O88F0HWbYCFuj6QBDWMvZdugVcrB4ZCCKc8eKmrVFWOcVIQ73GkTP6YbM8rIzrKyNki53xQHX/N9DmsKq1Gypo0Bd729/V71WJVVCZ9kU98jUpou2VL3jSnodTTFaMUYw== 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 1/22/26 07:41, Harry Yoo wrote: > On Fri, Jan 16, 2026 at 03:40:38PM +0100, Vlastimil Babka wrote: >> The changes related to sheaves made the description of locking and other >> details outdated. Update it to reflect current state. >> >> Also add a new copyright line due to major changes. >> >> Reviewed-by: Suren Baghdasaryan >> Signed-off-by: Vlastimil Babka >> --- >> @@ -112,47 +123,46 @@ >> + * node->barn->lock (spinlock) >> * >> - * lockless fastpaths >> + * Lockless freeing >> + * >> + * Objects may have to be freed to their slabs when they are from a remote >> + * node (where we want to avoid filling local sheaves with remote objects) >> + * or when there are too many full sheaves. On architectures supporting >> + * cmpxchg_double this is done by a lockless update of slab's freelist and >> + * counters, otherwise slab_lock is taken. This only needs to take the >> + * list_lock if it's a first free to a full slab, or when there are too many >> + * fully free slabs and some need to be discarded. > > nit: "or when a slab becomes empty after the free"? > because we don't check nr_partial before acquiring list_lock. > > With that addressed, > Reviewed-by: Harry Yoo Good point, thanks!