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Wed, 21 Jan 2026 08:12:34 +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 LzYMBnKKcGlibgAAD6G6ig (envelope-from ); Wed, 21 Jan 2026 08:12:34 +0000 Message-ID: <89a3304d-ee46-4498-8a04-fe48d4644b75@suse.cz> Date: Wed, 21 Jan 2026 09:12:33 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 05/21] slab: add sheaves to most caches Content-Language: en-US To: Breno Leitao Cc: Harry Yoo , 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-v3-5-5595cb000772@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-Action: no action X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 9BEB280005 X-Stat-Signature: hnrw1mnqbpdpigbsdg3dtwtz887o9rmd X-Rspam-User: X-HE-Tag: 1768983157-564319 X-HE-Meta: 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 wfmooFsB h4NZjRiSxixP8a+/hn3WhHm/uejF2XY/DH8IJ+H3vhsAK/NifEg0VI7v/rexnBA6efCbRgbSV9J2MtGOUhxN0/f5EavNsr5AFNwNXhjK1MdBkSHdgAr25tmYYOg+xH9uvsPtcu0D/adEJLhonJ5YjzY3md/X/sGsSexmxCvXbu8coAmAIN/+XurUdTEwdZmLBid92gSbAuCPbh6hsidAZ8lrde8RSnL03sZdllteqLUwBS6ESdVN4eemID7S8XcFPyNksFjYq3sIFVl6sTZiBJtB75RqfslM4lKwY 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 1/20/26 19:47, Breno Leitao wrote: > Hello Vlastimil, > > On Fri, Jan 16, 2026 at 03:40:25PM +0100, Vlastimil Babka wrote: >> --- a/mm/slub.c >> +++ b/mm/slub.c >> @@ -7863,6 +7863,48 @@ static void set_cpu_partial(struct kmem_cache *s) >> #endif >> } >> >> +static unsigned int calculate_sheaf_capacity(struct kmem_cache *s, >> + struct kmem_cache_args *args) >> + >> +{ >> + unsigned int capacity; >> + size_t size; >> + >> + >> + if (IS_ENABLED(CONFIG_SLUB_TINY) || s->flags & SLAB_DEBUG_FLAGS) >> + return 0; >> + >> + /* bootstrap caches can't have sheaves for now */ >> + if (s->flags & SLAB_NO_OBJ_EXT) >> + return 0; > > I've been testing this on my arm64 environment with some debug patches, > and the machine became unbootable. > > I am wondering if you should avoid SLAB_NOLEAKTRACE as well. I got the > impression it is hitting this infinite loop: > > -> slab allocation > -> kmemleak_alloc() > -> kmem_cache_alloc(object_cache) > -> alloc_from_pcs() / __pcs_replace_empty_main() > -> alloc_full_sheaf() -> kzalloc() > -> kmemleak_alloc() > -> ... (infinite recursion) > Oops. > What about something as: > > diff --git a/mm/slub.c b/mm/slub.c > index 26804859821a..0a6481aaa744 100644 > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -7445,8 +7445,13 @@ static unsigned int calculate_sheaf_capacity(struct kmem_cache *s, > if (IS_ENABLED(CONFIG_SLUB_TINY) || s->flags & SLAB_DEBUG_FLAGS) > return 0; > > - /* bootstrap caches can't have sheaves for now */ > - if (s->flags & SLAB_NO_OBJ_EXT) > + /* > + * bootstrap caches can't have sheaves for now (SLAB_NO_OBJ_EXT). > + * SLAB_NOLEAKTRACE caches (e.g., kmemleak's object_cache) must not > + * have sheaves to avoid recursion when sheaf allocation triggers > + * kmemleak tracking. > + */ > + if (s->flags & (SLAB_NO_OBJ_EXT | SLAB_NOLEAKTRACE)) > return 0; Yeah that should work, will do. Thanks a lot!