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b=Z/Hz3X/TPQ0VoTzcd2HVktVxCuT0+EELVKLXuVhqWF0qfgtYpRR8npVrrzrappR8f 00mMnKynMXuAHrUaW2FohSrbnYznm493AVwronQ3ivtE33wY+oED7oGy+unHEwy8qf BdlcAOQeLpKhu+CAAz145Splmlihk/eXwRsxQ1wc1kqv8VmSktzz/PbDS4i1cnmDs+ ZqjHVGbRcXwKaL+SD4O9SpU0TA4ZA+6OphJYEHSWi9C4dcYbm8M+yQjCa9QkRO362X ihE4Ymkcn7Q/AOM9ALUlfbwUN1y0I9lSBawZbWDRoBAZYnbnTTj+SQ0yRIxgGvvi1j 5EDNrKl0hTY8A== From: SeongJae Park To: Bijan Tabatabai Cc: SeongJae Park , damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, akpm@linux-foundation.org, corbet@lwn.net, joshua.hahnjy@gmail.com, bijantabatab@micron.com, venkataravis@micron.com, emirakhur@micron.com, ajayjoshi@micron.com, vtavarespetr@micron.com, Ravi Shankar Jonnalagadda Subject: Re: [RFC PATCH v3 11/13] mm/damon/vaddr: Use damos->migrate_dests in migrate_{hot,cold} Date: Wed, 2 Jul 2025 17:32:29 -0700 Message-Id: <20250703003229.57429-1-sj@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250702201337.5780-12-bijan311@gmail.com> References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 4ECA7140002 X-Stat-Signature: x89birydzdsknh7jgotze9b4gnby3cso X-HE-Tag: 1751502753-978091 X-HE-Meta: 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 GTw3eeNW Gs5SNlRazz637p6IAx4OwrFi8+ufozfyG8n1OXRsNY9I+w9uhcg0Qn1AWfZYTeqb4Jfs0Si2e8epFtWUHvdJJ0n/9JhcaJ5Hfal93USaCfcszxCgV815eE+9RPC06nEm/fjkoXl6PlJmQHe/Aj1J1fj1mb/LjRGvrPiEhPUxh298OOYlniPJndL7baA9iahIVa5jRSwv9VY63AmJtV9SPvlFkG7iLd6U4rAvRAqjG+u+vO6CLu/Jg+cR5SQ8ZiBzzPzJzPbziB07RI+3yblB45Fjgy698OAtefDSz9KrS63VhqOEKD4JKu1Al87ykeoTEyq3f2J5rC6hcKe+clRX8wHcRwva5WNGa8Ry42jV8DvgZx5EBpV/C7KXsKl3eQXtX2IpJdJk8dSVPQcdCfapiUcQIV771kaL+vIIzp8c8PTvJH1zcKqQkh1ry+XhKEUZLYeiN 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 Wed, 2 Jul 2025 15:13:34 -0500 Bijan Tabatabai wrote: > From: Bijan Tabatabai > > damos->migrate_dests provides a list of nodes the migrate_{hot,cold} > actions should migrate to, as well as the weights which specify the > ratio pages should be migrated to each destination node. > > This patch interleaves pages in the migrate_{hot,cold} actions according > to the information provided in damos->migrate_dests if it is used. The > interleaving algorithm used is similar to the one used in > weighted_interleave_nid(). If damos->migration_dests is not provided, the > actions migrate pages to the node specified in damos->target_nid as > before. > > Co-developed-by: Ravi Shankar Jonnalagadda > Signed-off-by: Ravi Shankar Jonnalagadda > Signed-off-by: Bijan Tabatabai > --- > mm/damon/vaddr.c | 114 ++++++++++++++++++++++++++++++++++++++++------- > 1 file changed, 97 insertions(+), 17 deletions(-) > > diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c > index 5cdfdc47c5ff..5f230a427fdc 100644 > --- a/mm/damon/vaddr.c > +++ b/mm/damon/vaddr.c > @@ -611,11 +611,76 @@ static unsigned int damon_va_check_accesses(struct damon_ctx *ctx) > return max_nr_accesses; > } > > +struct damos_va_migrate_private { > + struct list_head *migration_lists; > + struct damos *scheme; > +}; > + > +/* > + * Place the given folio in the migration_list corresponding to where the folio > + * should be migrated. > + * > + * The algorithm used here is similar to weighted_interleave_nid() > + */ > +static void damos_va_migrate_folio(struct folio *folio, > + struct vm_area_struct *vma, unsigned long addr, > + struct damos_migrate_dests *dests, > + struct list_head *migration_lists) Based on the name, I was thinking the function may do the real migration. What about using more self-introductory name, say, damos_va_migrate_dests_add()? > +{ > + pgoff_t ilx; > + int order; > + unsigned int target; > + unsigned int weight_total = 0; > + int i; > + > + /* > + * If dests is empty, there is only one migration list corresponding > + * to s->target_nid. > + */ > + if (!dests->nr_dests) { > + i = 0; > + goto isolate; > + } > + > + order = folio_order(folio); > + ilx = vma->vm_pgoff >> order; > + ilx += (addr - vma->vm_start) >> (PAGE_SHIFT + order); > + > + for (i = 0; i < dests->nr_dests; i++) > + weight_total += dests->weight_arr[i]; > + > + /* If the total weights are somehow 0, don't migrate at all */ > + if (!weight_total) > + return; > + > + target = ilx % weight_total; > + for (i = 0; i < dests->nr_dests; i++) { > + if (target < dests->weight_arr[i]) > + break; > + target -= dests->weight_arr[i]; > + } > + > + /* No index being chosen indicates a mistake in the algorithm */ > + if (i == dests->nr_dests) { > + WARN_ONCE(1, "Error determining target interleave node"); > + return; > + } This cannot happen, right? Let's just remove this. > + > +isolate: > + if (!folio_isolate_lru(folio)) > + return; > + > + list_add(&folio->lru, &migration_lists[i]); > +} > + > #ifdef CONFIG_TRANSPARENT_HUGEPAGE > static int damos_va_migrate_pmd_entry(pmd_t *pmd, unsigned long addr, > unsigned long next, struct mm_walk *walk) > { > - struct list_head *migration_list = walk->private; > + struct damos_va_migrate_private *priv = walk->private; > + struct damos *s = priv->scheme; > + struct list_head *migration_lists = priv->migration_lists; > + struct damos_migrate_dests *dests = &s->migrate_dests; Seems priv->sheme is only a carrier of ->migrate_dests. Why don't you add that in damos_va_migrate_private directly? > struct folio *folio; > spinlock_t *ptl; > pmd_t pmde; > @@ -630,12 +695,8 @@ static int damos_va_migrate_pmd_entry(pmd_t *pmd, unsigned long addr, > if (!folio) > goto unlock; > > - if (!folio_isolate_lru(folio)) > - goto put_folio; > - > - list_add(&folio->lru, migration_list); > + damos_va_migrate_folio(folio, walk->vma, addr, dests, migration_lists); > > -put_folio: > folio_put(folio); > unlock: > spin_unlock(ptl); > @@ -648,7 +709,10 @@ static int damos_va_migrate_pmd_entry(pmd_t *pmd, unsigned long addr, > static int damos_va_migrate_pte_entry(pte_t *pte, unsigned long addr, > unsigned long enxt, struct mm_walk *walk) > { > - struct list_head *migration_list = walk->private; > + struct damos_va_migrate_private *priv = walk->private; > + struct damos *s = priv->scheme; > + struct list_head *migration_lists = priv->migration_lists; > + struct damos_migrate_dests *dests = &s->migrate_dests; > struct folio *folio; > pte_t ptent; > > @@ -660,12 +724,8 @@ static int damos_va_migrate_pte_entry(pte_t *pte, unsigned long addr, > if (!folio) > return 0; > > - if (!folio_isolate_lru(folio)) > - goto out; > - > - list_add(&folio->lru, migration_list); > + damos_va_migrate_folio(folio, walk->vma, addr, dests, migration_lists); > > -out: > folio_put(folio); > return 0; > } > @@ -717,34 +777,54 @@ static unsigned long damos_va_migrate(struct damon_target *target, > struct damon_region *r, struct damos *s, > unsigned long *sz_filter_passed) > { > - LIST_HEAD(folio_list); > + struct damos_va_migrate_private priv; > struct task_struct *task; > struct mm_struct *mm; > + int nr_dests; > + int nid; > + bool use_target_nid; > unsigned long applied = 0; > + struct damos_migrate_dests *dests = &s->migrate_dests; > struct mm_walk_ops walk_ops = { > .pmd_entry = damos_va_migrate_pmd_entry, > .pte_entry = damos_va_migrate_pte_entry, > .walk_lock = PGWALK_RDLOCK, > }; > > + use_target_nid = dests->nr_dests == 0; > + nr_dests = use_target_nid ? 1 : dests->nr_dests; > + priv.scheme = s; > + priv.migration_lists = kmalloc_array(nr_dests, > + sizeof(struct list_head), GFP_KERNEL); sizeof(*priv.migration_lists)? > + if (!priv.migration_lists) > + return 0; > + > + for (int i = 0; i < nr_dests; i++) > + INIT_LIST_HEAD(&priv.migration_lists[i]); > + > task = damon_get_task_struct(target); > if (!task) > - return 0; > + goto free_lists; > > mm = damon_get_mm(target); > if (!mm) > goto put_task; > > mmap_read_lock(mm); > - walk_page_range(mm, r->ar.start, r->ar.end, &walk_ops, &folio_list); > + walk_page_range(mm, r->ar.start, r->ar.end, &walk_ops, &priv); > mmap_read_unlock(mm); > mmput(mm); > > - applied = damon_migrate_pages(&folio_list, s->target_nid); > - cond_resched(); > + for (int i = 0; i < nr_dests; i++) { > + nid = use_target_nid ? s->target_nid : dests->node_id_arr[i]; > + applied += damon_migrate_pages(&priv.migration_lists[i], nid); > + cond_resched(); > + } > > put_task: > put_task_struct(task); > +free_lists: > + kfree(priv.migration_lists); > return applied * PAGE_SIZE; > } > > -- > 2.43.5 > > Thanks, SJ