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Thu, 22 Jan 2026 09:30:44 +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 ehY/JUTucWkoCwAAD6G6ig (envelope-from ); Thu, 22 Jan 2026 09:30:44 +0000 Message-ID: <792c6837-137b-4667-8c4e-fdc988ae8878@suse.cz> Date: Thu, 22 Jan 2026 10:30:44 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 21/21] mm/slub: cleanup and repurpose some stat items Content-Language: en-US To: Hao Li Cc: Harry Yoo , Petr Tesarik , Christoph Lameter , David Rientjes , Roman Gushchin , 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-v3-21-5595cb000772@suse.cz> <5rmxfyxuhloucetufg2qic5elgi6frd7onjzdsosmhtjdqglij@5htmiqrdhkoj> 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: <5rmxfyxuhloucetufg2qic5elgi6frd7onjzdsosmhtjdqglij@5htmiqrdhkoj> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Action: no action X-Stat-Signature: cgmobca89b1emndcggz77dbp5up1ai39 X-Rspamd-Queue-Id: 110EE14000D X-Rspam-User: X-Rspamd-Server: rspam04 X-HE-Tag: 1769074246-631695 X-HE-Meta: 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 V9XyFpr5 8PVbQSTtEAFgh3pvQ4xygShFHf87+zMBeS2mXqbkfAQFWQAO6Ut1fUgafj4SLiQcOVPlyX7q9vPmDXPflgeiatVc1C4bfeTQ4aeP4n0hRfBivBfFxBWrL/AgcyZLz8u1R6b6yXt+6Sn4cPmc9D81HJ08pNJgJMMU2ETOjFXThFFAI3huwIBriTuNKmRKfPTZ0VnPb+xyOtGAF6aq/G2KOPwJCrXuZcKKHTA66SpkfSBa9gcu23eUpb8J6RTcrG9QxaPxLN5wgRAbJvRM= 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 06:52, Hao Li wrote: > On Fri, Jan 16, 2026 at 03:40:41PM +0100, Vlastimil Babka wrote: >> A number of stat items related to cpu slabs became unused, remove them. >> >> Two of those were ALLOC_FASTPATH and FREE_FASTPATH. But instead of >> removing those, use them instead of ALLOC_PCS and FREE_PCS, since >> sheaves are the new (and only) fastpaths, Remove the recently added >> _PCS variants instead. >> >> Change where FREE_SLOWPATH is counted so that it only counts freeing of >> objects by slab users that (for whatever reason) do not go to a percpu >> sheaf, and not all (including internal) callers of __slab_free(). Thus >> flushing sheaves (counted by SHEAF_FLUSH) no longer also increments >> FREE_SLOWPATH. This matches how ALLOC_SLOWPATH doesn't count sheaf >> refills (counted by SHEAF_REFILL). >> >> Reviewed-by: Suren Baghdasaryan >> Signed-off-by: Vlastimil Babka >> --- >> mm/slub.c | 77 +++++++++++++++++---------------------------------------------- >> 1 file changed, 21 insertions(+), 56 deletions(-) >> >> diff --git a/mm/slub.c b/mm/slub.c >> index c12e90cb2fca..d73ad44fa046 100644 >> --- a/mm/slub.c >> +++ b/mm/slub.c >> @@ -330,33 +330,19 @@ enum add_mode { >> }; >> >> enum stat_item { >> - ALLOC_PCS, /* Allocation from percpu sheaf */ >> - ALLOC_FASTPATH, /* Allocation from cpu slab */ >> - ALLOC_SLOWPATH, /* Allocation by getting a new cpu slab */ >> - FREE_PCS, /* Free to percpu sheaf */ >> + ALLOC_FASTPATH, /* Allocation from percpu sheaves */ >> + ALLOC_SLOWPATH, /* Allocation from partial or new slab */ >> FREE_RCU_SHEAF, /* Free to rcu_free sheaf */ >> FREE_RCU_SHEAF_FAIL, /* Failed to free to a rcu_free sheaf */ >> - FREE_FASTPATH, /* Free to cpu slab */ >> - FREE_SLOWPATH, /* Freeing not to cpu slab */ >> + FREE_FASTPATH, /* Free to percpu sheaves */ >> + FREE_SLOWPATH, /* Free to a slab */ > > Nits: Would it make sense to add stat(s, FREE_SLOWPATH) in > free_deferred_objects() as well, since it also calls __slab_free()? Yeah. > Everything else looks good. > > This patchset replaces cpu slab with cpu sheaves and really simplifies the code > overall - I really like the direction and the end result. It's really been a > pleasure reviewing this series. Thanks! > > Reviewed-by: Hao Li Thanks a lot for the thorough review!