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Rao's message of "Thu, 14 Aug 2025 19:18:21 +0530") References: <20250814134826.154003-1-bharata@amd.com> <20250814134826.154003-3-bharata@amd.com> Date: Fri, 15 Aug 2025 09:39:59 +0800 Message-ID: <87a541e51s.fsf@DESKTOP-5N7EMDA> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: DB21640004 X-Stat-Signature: 76fyscewi13udcipqa5qh3epds94rg37 X-Rspam-User: X-HE-Tag: 1755222005-877583 X-HE-Meta: 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 sVZVfCoC 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 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: Bharata B Rao writes: > From: Gregory Price > > A common operation in tiering is to migrate multiple pages at once. Is it common now? If so, you can replace some callers of migrate_misplaced_folio() with migrate_misplaced_folios_batch(). > The migrate_misplaced_folio function requires one call for each IMHO, migrate_misplaced_folio() is more concise than migrate_misplaced_folio function. > individual folio. Expose a batch-variant of the same call for use > when doing batch migrations. > > Signed-off-by: Gregory Price > Signed-off-by: Bharata B Rao > --- > include/linux/migrate.h | 6 ++++++ > mm/migrate.c | 31 +++++++++++++++++++++++++++++++ > 2 files changed, 37 insertions(+) > > diff --git a/include/linux/migrate.h b/include/linux/migrate.h > index acadd41e0b5c..0593f5869be8 100644 > --- a/include/linux/migrate.h > +++ b/include/linux/migrate.h > @@ -107,6 +107,7 @@ static inline int migrate_huge_page_move_mapping(struct address_space *mapping, > int migrate_misplaced_folio_prepare(struct folio *folio, > struct vm_area_struct *vma, int node); > int migrate_misplaced_folio(struct folio *folio, int node); > +int migrate_misplaced_folios_batch(struct list_head *foliolist, int node); > #else > static inline int migrate_misplaced_folio_prepare(struct folio *folio, > struct vm_area_struct *vma, int node) > @@ -117,6 +118,11 @@ static inline int migrate_misplaced_folio(struct folio *folio, int node) > { > return -EAGAIN; /* can't migrate now */ > } > +static inline int migrate_misplaced_folios_batch(struct list_head *foliolist, > + int node) > +{ > + return -EAGAIN; /* can't migrate now */ > +} > #endif /* CONFIG_NUMA_BALANCING */ > > #ifdef CONFIG_MIGRATION > diff --git a/mm/migrate.c b/mm/migrate.c > index 7e356c0b1b5a..1268a95eda0e 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -2714,5 +2714,36 @@ int migrate_misplaced_folio(struct folio *folio, int node) > BUG_ON(!list_empty(&migratepages)); > return nr_remaining ? -EAGAIN : 0; > } > + > +/* > + * Batch variant of migrate_misplaced_folio. Attempts to migrate > + * a folio list to the specified destination. > + * > + * Caller is expected to have isolated the folios by calling > + * migrate_misplaced_folio_prepare(), which will result in an > + * elevated reference count on the folio. > + * > + * This function will un-isolate the folios, dereference them, and > + * remove them from the list before returning. > + */ > +int migrate_misplaced_folios_batch(struct list_head *folio_list, int node) In addition to working on a list of folios instead of single folio, I found there are some difference about memcg counting between migrate_misplaced_folios_batch() and migrate_misplace_folio(). Why? And, can we merge the implementation of two functions to reduce code duplication? > +{ > + pg_data_t *pgdat = NODE_DATA(node); > + unsigned int nr_succeeded; > + int nr_remaining; > + > + nr_remaining = migrate_pages(folio_list, alloc_misplaced_dst_folio, > + NULL, node, MIGRATE_ASYNC, > + MR_NUMA_MISPLACED, &nr_succeeded); > + if (nr_remaining) > + putback_movable_pages(folio_list); > + > + if (nr_succeeded) { > + count_vm_numa_events(NUMA_PAGE_MIGRATE, nr_succeeded); > + mod_node_page_state(pgdat, PGPROMOTE_SUCCESS, nr_succeeded); > + } > + BUG_ON(!list_empty(folio_list)); > + return nr_remaining ? -EAGAIN : 0; > +} > #endif /* CONFIG_NUMA_BALANCING */ > #endif /* CONFIG_NUMA */ --- Best Regards, Huang, Ying