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b=oyWy87D2HsyvaSuz6Y7G6vhv6Mfp81D3sIv50QRIaDaq19WokIWz8vhdH+0htZQp0 DQO4apVKJ7BW8j1BmtfvA45GttkH13CJeuE1yF6LVnbNZgH08Pjt2Gcm7BxyDYDLpA aJAmesjjc7A9bECK4kXjIRnavfGJ2YW5NMY6z166RU+cxn/fNM/kQ3qXTjaU0KAbRH paqPiSdjGCpBzj4OfohAU9A7k74IZcdZY3VG22Pu5Jyzq0lkNxP/5d7cdGrGrHFIzP F+xIO8pz4wrHUjFR+jnbWJN27CNEmegtOb73cAI8f4+0DVdic/y3tBlKpd812MEMwx 3hIxSHQOQxyRw== From: SJ Park To: SJ Park Cc: Aveline Noir , Andrew Morton , damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Bijan Tabatabai , Bijan Tabatabai Subject: Re: [PATCH] mm/damon: skip folios already on the migration target node Date: Wed, 28 Oct 2026 18:06:10 -0700 Message-ID: <20261029010611.170686-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20261029010144.169906-1-sj@kernel.org> References: X-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 3844E20003 X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=4.0.1 X-Stat-Signature: ky5kq6gdy6cpdyxzr8woj8u4dijx7nbg X-HE-Tag: 1793235979-274093 X-HE-Meta: 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 4Kk9SGPw 4UGunfD1wNI2y3ODmrNmSoTInTnbffwRAS9vvFqxj7FZ4ojOZTAqVuiM8zI3nWalA0fT6/9SUd8a6sw7g4pUr8xNbtg5ilDymUfD6FABanAF5Lsa9OPOpTX7CkMIiEgw/A1ASJSuD4mCRp/Hx3mmSPYBNb+MWvPkc/ckDCMypPrEL+SLpplHzmu8liwozOiPBU7VHcSG1G3OxROeDWLnk0XoryXmU09IHhKHuMAj8BjzYPG3pxipUooakLxrtx9opigTlseSzvooDCqGGIWD13xyW5g== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 One more trivial nit. Let's use 'mm/damon/{p,v}addr:' as the subject prefix. On Wed, 28 Oct 2026 18:01:43 -0700 SJ Park wrote: > On Thu, 29 Oct 2026 00:05:46 +1100 Aveline Noir wrote: > > > While measuring DAMOS migration overhead, I found that the target_nid > > path isolates folios already on the target node, then puts them back on > > the LRU without migrating them. > > > > Skip them before isolation in vaddr and paddr, as the vaddr explicit > > destinations path already does. > > Nice catch! > > > > > Signed-off-by: Aveline Noir > > Other than below trivial nit, > > Reviewed-by: SJ Park > > > > > --- > > DAMON KUnit and selftests all passed. In a synthetic same-node fvaddr > > test on a two-node x86-64 KVM guest (8 interleaved runs per kernel), > > guest-kernel cycles fell by about 29% > > with 4 KiB regions and 90% with 16 MiB regions. Median kdamond CPU > > time fell by about 76% with 16 MiB regions, with no clear change > > with 4 KiB regions. > > Thank you for sharing the test result. We don't want to add too much test > results in the commit message. But the performance part above is informative > and concise, so I think it deserves to be in the commit message. > > > --- > > mm/damon/paddr.c | 2 ++ > > mm/damon/vaddr.c | 22 ++++++++++++---------- > > 2 files changed, 14 insertions(+), 10 deletions(-) > [...] > > @@ -858,8 +860,8 @@ static int damos_va_migrate_pmd_entry(pmd_t *pmd, unsigned long addr, > > goto huge_out; > > if (damos_va_filter_out(s, folio, walk->vma, addr, NULL, pmd)) > > goto huge_out; > > - damos_va_migrate_dests_add(folio, walk->vma, addr, dests, > > - migration_lists); > > + damos_va_migrate_dests_add(folio, walk->vma, addr, s, > > + migration_lists); > > Let's not align parameters on parentheses but just give two tabs indentation. > > > huge_out: > > spin_unlock(ptl); > > return 0; > > @@ -883,8 +885,8 @@ static int damos_va_migrate_pmd_entry(pmd_t *pmd, unsigned long addr, > > continue; > > if (damos_va_filter_out(s, folio, walk->vma, addr, pte, NULL)) > > continue; > > - damos_va_migrate_dests_add(folio, walk->vma, addr, dests, > > - migration_lists); > > + damos_va_migrate_dests_add(folio, walk->vma, addr, s, > > + migration_lists); > > Ditto. > > Assuming you accept my humble suggestions above, I applied this patch to > damon/next [1] tree, together with my above suggestions. I will repost it for > mm.git inclusion within a week. So, no action from your side is needed for > now. Let me know if you think changes to the plan or discussions are needed. I also added the suggested subject prefix in damon/next tree. Please feel free to let me know if you have an opinion. > > [1] https://origin.kernel.org/doc/html/latest/mm/damon/maintainer-profile.html#scm-trees Thanks, SJ [...]