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Fri, 24 Jul 2026 22:30:32 -0700 (PDT) Received: from google.com ([2a00:79e0:2031:6:fbee:e165:c3f8:38a4]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2cfde7bbdacsm4958385ad.47.2026.07.24.22.30.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 24 Jul 2026 22:30:32 -0700 (PDT) Date: Sat, 25 Jul 2026 14:30:27 +0900 From: Sergey Senozhatsky To: "Barry Song (Xiaomi)" Cc: senozhatsky@chromium.org, akpm@linux-foundation.org, haowenchao22@gmail.com, haowenchao@xiaomi.com, joshua.hahnjy@gmail.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, minchan@kernel.org, nphamcs@gmail.com Subject: Re: [PATCH v6 0/4] mm/zsmalloc: reduce lock contention in zs_free() Message-ID: References: <20260725035733.53241-1-baohua@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260725035733.53241-1-baohua@kernel.org> X-Rspamd-Queue-Id: A80191A0006 X-Rspam-User: X-Stat-Signature: 87zxe6b9er1wym9udsxs7gce5ngdnuoq X-Rspamd-Server: rspam04 X-HE-Tag: 1784957433-245680 X-HE-Meta: U2FsdGVkX18GGqjyP6p88tRlDity87iC3g9o7pg9Fp7jCt8lHX9SVTZr4LcuSBYftJSzKYgFpJ97EXbA4SvO+yxaKMsyrigQKbk6qeW8/uwGAinUm+u9Zbm1u/iIFLkOJR8GI7qvMoMCT2anH2fgR9hp/CymxWsqPweLuYEsCtZzndUcyF6NmQ3oujDI7n2YqvbIRWgRKMnzJM6Kp3a3E1KJE4ea9+kT/LeMBp9XFZfLNJAT/UFwQhj6AAcKgfEvzIo1II2QK+NF1QU7eNIgCB5VLSfz+ULy7+zI3cdzPWeFt7bCilJhoqiW8q/1D+8o0+FDBm5COIiYO/8C2JGwJsYHhk98Qbi0dISK4Ocihv8D9UJHLcQx8nC+anI6er23N7nbdFZeHFgH8oRHBHPQt7bqQIVta5E/NzJfDnS15RWWevrPH8Q80Lg4ZO6cXhwoTeXmShJbxmP20mosd/m+XBW+c7PfsdgGiScQr9kcGLaChnWGxrL30lrEkmtF14XGM3jForK6H+sDmCWWYMjwD+xSEQItGMmwO9/7H8/rbN2+5EZfvJ6cyX58IxQGZAlK9hGNkhJZw3PvXrcHthlP1S4gCrB9SlR+zCWQoTtPzfwT1afG33SlTBZOoC1fdbzculUlPQtsY+jUqgQliba0QrONn21ScEXZMaivGvJooE+AwTqu/DmEmNxze+5NEjUY5UqNHW7sWETtQm/NoSdsfgzPiEULRPPexEEigZQLuS2czyCC0SNdyyIXFArSSpYpSrecKl/CXpCh59l/hEgP27H8MP+bw2AjkDP8C8ewRWyXiHBxTK8MVwTa4xiCm/qO0eU6bg7c3yp2pIwMaeXfiT1okxX2sHeJ+AWcs9WT9ubDKOfavzYp/iXrGfaI5YOHW34OAztkopNeoRRqCbtsR3uMx69+1dWbEHCjLDxG4ozelVEUboSzKxR6geI7Wu+cMAY2uBr0p09u0ExbHTs z3jE9hj5 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On (26/07/25 11:57), Barry Song (Xiaomi) wrote: > On Fri, Jul 24, 2026 at 12:55 PM Sergey Senozhatsky wrote: > > > > Apologies for the delay. > > > > On (26/06/27 21:36), Andrew Morton wrote: > > [..] > > > > Raspberry Pi 4B (4-core ARM64 Cortex-A72): > > > > > > > >   mode        Base       Patched     Speedup > > > >   single      59.0ms     56.0ms      1.05x > > > >   multi 2p    94.6ms     66.7ms      1.42x > > > >   multi 4p    202.9ms    110.6ms     1.83x > > > > > > > > x86 (20-core Intel i7-12700, 16 concurrent processes): > > > > > > > >   mode        Base       Patched     Speedup > > > >   single      11.7ms     9.8ms       1.19x > > > >   multi 2p    24.1ms     17.2ms      1.40x > > > >   multi 4p    63.0ms     45.3ms      1.39x > > > > > > Well that's a nice result. > > > > Indeed. > > > > > Sashiko AI review said ....  nothing.  I don't recall seeing that > > > before ;) > > > > grep-ing the code, I wonder if we maybe want to tweak some comments. > > Namely, zs_page_migrate() says: > > > >         The pool migrate_lock protects the race between zpage migration > >         and zs_free > > > > which is not entirely true anymore, as zs_free() has a lockless path > > that doesn't take pool look (when ZS_OBJ_CLASS_BITS permit). > > > > Likewise, __zs_compact() says the following about pool migrate_lock: > > > >         protect the race between zpage migration and zs_free > > > > None of these are critical, very minor. > > Does it look good to you if we squash the below change into patch2/4: Sure, looks good to me!