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client-ip=165.204.84.17; helo=satlexmb07.amd.com; pr=C Received: from satlexmb07.amd.com (165.204.84.17) by BN1PEPF00004683.mail.protection.outlook.com (10.167.243.89) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.382.8 via Frontend Transport; Wed, 2 Sep 2026 10:53:10 +0000 Received: from [127.0.1.1] (10.180.168.240) by satlexmb07.amd.com (10.181.42.216) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.46; Wed, 2 Sep 2026 05:52:56 -0500 From: Shivank Garg Date: Wed, 2 Sep 2026 10:52:16 +0000 Subject: [PATCH RFC 02/11] mm/migrate: handle retries in migrate_folios_move() Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-ID: <20260902-migrate-refactor-shivank-v1-2-9dcca87669c4@amd.com> References: <20260902-migrate-refactor-shivank-v1-0-9dcca87669c4@amd.com> In-Reply-To: <20260902-migrate-refactor-shivank-v1-0-9dcca87669c4@amd.com> To: Andrew Morton , David Hildenbrand , Zi Yan , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Gregory Price , Ying Huang , "Alistair Popple" , Vlastimil Babka , "Suren Baghdasaryan" , Michal Hocko , "Brendan Jackman" , Johannes Weiner , "SJ Park" , Jason Gunthorpe , John Hubbard , Peter Xu , Miaohe Lin , Naoya Horiguchi , "Oscar Salvador" , Kairui Song , Qi Zheng , Shakeel Butt , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Lorenzo Stoakes , "Matthew Wilcox (Oracle)" , Jan Kara , Jonathan Corbet , Shuah Khan , Randy Dunlap , "Alexander Viro" , Christian Brauner , Benjamin LaHaise , Chris Mason , David Sterba , Muchun Song , Dave Kleikamp , Trond Myklebust , Anna Schumaker , Mike Rapoport , Sean Christopherson , Paolo Bonzini , Bharata B Rao , David Rientjes , "Yiannis Nikolakopoulos" CC: , , , , , , , , , , , Shivank Garg X-Mailer: b4 0.15-dev-47d62 X-Developer-Signature: v=1; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: 166o3IsiLT4XRf6KeNYrIh27+Su+2jotCPja4qHH8WVaE8e1+AOn2oABcnQavHvHINQbVX8EREvojV+RG9cFja6lDgvJEGpiPHH+5juuuDJiyvGZvW7C6ns0Gi3Sa+fc76hkSRaduHmmAbD9+PW1Mu/7xmGOIzX2rIO5hg5m4Lnk8C9xe6GTqbEN3HhuILK5/XmfU3QTtNPWuZLcFpdlVikBiPpH4kTonLrIaGoKG89PJxFuoK/OYTzXkNen5PC0/xBgMhfsn1bZPkvK2UhNTZ7Xjhlc1LdqtGIXGSsEqLktw7BFONNWGFBuVe56vPBUqbGSVXJf/RCjEH+cV86LlrWtAXrzvkZ1frNffghBMhl+Zgf298y/WToYCDPAVkYB2GjcFPsP8Mh8O4SnNOh3u1LZpoXHCeTr8rSlISrmY4HYuSspebLCKUQj8SAzq+9A X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 02 Sep 2026 10:53:10.3692 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 30478cca-e29d-421e-b75e-08df08e06110 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[satlexmb07.amd.com] X-MS-Exchange-CrossTenant-AuthSource: BN1PEPF00004683.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS0PR12MB9060 After extracting the unmap phase, migrate_pages_batch() still drives the retry loop for the move phase and passes its retry bookkeeping to migrate_folios_move(). This splits the move phase across the two functions and requires several output parameters. Move the retry loop and its bookkeeping into migrate_folios_move(). The function now takes the number of passes and reports failures through @nr_failed, matching migrate_folios_unmap(). No functional change is intended. Signed-off-by: Shivank Garg --- mm/migrate.c | 104 ++++++++++++++++++++++++++++------------------------------- 1 file changed, 49 insertions(+), 55 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index 14a0f84009c6..89207bf515b9 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1729,51 +1729,61 @@ static void migrate_folios_move(struct list_head *src_folios, free_folio_t put_new_folio, unsigned long private, enum migrate_mode mode, enum migrate_reason reason, struct list_head *ret_folios, - struct migrate_pages_stats *stats, - int *retry, int *thp_retry, int *nr_failed, - int *nr_retry_pages) + struct migrate_pages_stats *stats, int nr_pass, + int *nr_failed) { struct folio *folio, *folio2, *dst, *dst2; + int retry = 1; + int thp_retry = 0; + int nr_retry_pages = 0; bool is_thp; int nr_pages; - int rc; + int pass, rc; - dst = list_first_entry(dst_folios, struct folio, lru); - dst2 = list_next_entry(dst, lru); - list_for_each_entry_safe(folio, folio2, src_folios, lru) { - is_thp = folio_test_large(folio) && folio_test_pmd_mappable(folio); - nr_pages = folio_nr_pages(folio); + for (pass = 0; pass < nr_pass && retry; pass++) { + retry = 0; + thp_retry = 0; + nr_retry_pages = 0; - cond_resched(); + dst = list_first_entry(dst_folios, struct folio, lru); + dst2 = list_next_entry(dst, lru); + list_for_each_entry_safe(folio, folio2, src_folios, lru) { + is_thp = folio_test_large(folio) && folio_test_pmd_mappable(folio); + nr_pages = folio_nr_pages(folio); - rc = migrate_folio_move(put_new_folio, private, - folio, dst, mode, - reason, ret_folios); - /* - * The rules are: - * 0: folio will be freed - * -EAGAIN: stay on the src_folios list - * Other errno: put on ret_folios list - */ - switch (rc) { - case -EAGAIN: - *retry += 1; - *thp_retry += is_thp; - *nr_retry_pages += nr_pages; - break; - case 0: - stats->nr_succeeded += nr_pages; - stats->nr_thp_succeeded += is_thp; - break; - default: - *nr_failed += 1; - stats->nr_thp_failed += is_thp; - stats->nr_failed_pages += nr_pages; - break; + cond_resched(); + + rc = migrate_folio_move(put_new_folio, private, + folio, dst, mode, reason, ret_folios); + /* + * The rules are: + * 0: folio will be freed + * -EAGAIN: stay on the src_folios list + * Other errno: put on ret_folios list + */ + switch (rc) { + case -EAGAIN: + retry++; + thp_retry += is_thp; + nr_retry_pages += nr_pages; + break; + case 0: + stats->nr_succeeded += nr_pages; + stats->nr_thp_succeeded += is_thp; + break; + default: + *nr_failed += 1; + stats->nr_thp_failed += is_thp; + stats->nr_failed_pages += nr_pages; + break; + } + dst = dst2; + dst2 = list_next_entry(dst, lru); } - dst = dst2; - dst2 = list_next_entry(dst, lru); } + *nr_failed += retry; + stats->nr_thp_failed += thp_retry; + stats->nr_failed_pages += nr_retry_pages; } static void migrate_folios_undo(struct list_head *src_folios, @@ -2000,11 +2010,7 @@ static int migrate_pages_batch(struct list_head *from, struct list_head *ret_folios, struct list_head *split_folios, struct migrate_pages_stats *stats, int nr_pass) { - int retry = 1; - int thp_retry = 1; int nr_failed = 0; - int nr_retry_pages = 0; - int pass = 0; int rc, rc_saved; LIST_HEAD(unmap_folios); LIST_HEAD(dst_folios); @@ -2024,21 +2030,9 @@ static int migrate_pages_batch(struct list_head *from, /* Flush TLBs for all unmapped folios */ try_to_unmap_flush(); - retry = 1; - for (pass = 0; pass < nr_pass && retry; pass++) { - retry = 0; - thp_retry = 0; - nr_retry_pages = 0; - - /* Move the unmapped folios */ - migrate_folios_move(&unmap_folios, &dst_folios, - put_new_folio, private, mode, reason, - ret_folios, stats, &retry, &thp_retry, - &nr_failed, &nr_retry_pages); - } - nr_failed += retry; - stats->nr_thp_failed += thp_retry; - stats->nr_failed_pages += nr_retry_pages; + /* Move the unmapped folios */ + migrate_folios_move(&unmap_folios, &dst_folios, put_new_folio, private, + mode, reason, ret_folios, stats, nr_pass, &nr_failed); rc = rc_saved ? : nr_failed; out: -- 2.43.0