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Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Johannes Weiner , Qi Zheng , Shakeel Butt , Axel Rasmussen , Yuanchu Xie , Wei Xu , Michal Hocko Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Kairui Song , Zhang Peng X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1774514187; l=4560; i=zippermonkey@icloud.com; s=20260309; h=from:subject:message-id; bh=ktO5LArnI4nbf2Br6U60uWT52jrGYKbMW/1pY1vTAV4=; b=5HDL+iwXk5ZIHMD2sHDZce2sXUi1l4PSUe0l6Z5PfKPVYwRpMTMNrzp29VSjzU6qUn0ziUt7l ZVtcZRrpVWEAiuoZccoBfMD6hFBPZjSQoM334EkFcOWbefUOQX5gF14 X-Developer-Key: i=zippermonkey@icloud.com; a=ed25519; pk=tPCLpFnBfIyHsp0k7eaUTUREEa36bQNW/69X+NS8wBU= X-Proofpoint-ORIG-GUID: _StyBDbCn9ITzjn54h0Q8v7dkMDMWNON X-Authority-Info-Out: v=2.4 cv=eNgeTXp1 c=1 sm=1 tr=0 ts=69c4f033 cx=c_apl:c_pps:t_out a=2G65uMN5HjSv0sBfM2Yj2w==:117 a=2G65uMN5HjSv0sBfM2Yj2w==:17 a=IkcTkHD0fZMA:10 a=Yq5XynenixoA:10 a=x7bEGLp0ZPQA:10 a=YE32fvk_ji8A:10 a=VkNPw1HP01LnGYTKEx00:22 a=GvQkQWPkAAAA:8 a=w1dcpSADNQsu10hy-bYA:9 a=QEXdDO2ut3YA:10 a=J82S1U87d15UFHHUFZS8:22 a=R6HnoDE5lksTgPyyjrIf:22 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMzI2MDA2MiBTYWx0ZWRfX74mX4e3E0Qs+ AnnwNDs5h3WWcSYEiAHYUKvuiXNNIc6kqJgw8JzJBm0DjJWKP4ECo76VV7f4iigCpLlQIpRyaFn 7YDDHFr91e82VwTdIMW7/SX0iu/jWiAQiRXpDO0SnjQrkTAJAc5OjRARrOa0rJlYvAsO6tBnIKY nY79MDfovOsc3K8VcoxQiaS5D9HTVEmzS6eA1TRDTx/SO7p+gy6nr+9jJN2I2uM49P2p9vLbjy0 bM1lqgPKKr0WPcRityaKZBufgraOtRFyCY1irxd8YwTSsqbTuIxDMlqE0IlQlnF8kG63ZuwHXlw s7rjjxI8mZCnuStdnR0mjOGJ0ukyw9c4a8wxC7JTyMoXa5wfR/eA/voZGFq8yc= X-Proofpoint-GUID: _StyBDbCn9ITzjn54h0Q8v7dkMDMWNON X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-03-26_02,2026-03-24_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 mlxlogscore=716 spamscore=0 bulkscore=0 phishscore=0 malwarescore=0 clxscore=1015 adultscore=0 lowpriorityscore=0 mlxscore=0 classifier=spam authscore=0 adjust=0 reason=mlx scancount=1 engine=8.22.0-2601150000 definitions=main-2603260062 X-Rspam-User: X-Rspamd-Queue-Id: 4C27412000A X-Stat-Signature: 39mmrd8tmba1mwitj68a7s6hx9cussft X-Rspamd-Server: rspam06 X-HE-Tag: 1774514230-214774 X-HE-Meta: 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 CT2kVhbQ z0TSGhNQSIwa2qBJsqbC5KV04jxd7iW+dWGETwsLOV0G8irD0lTOhfduRIKiHPJnLc5bnhJxFyliem4lCTbQhXdW6bCb4OY9HqHF2IzSmpPV28y4IjeZPIZcbJGqohcqnwNlo/dCKxJN0QYcrir94bZRCMGa+QuhbfTB/cLBofWu4xuDYfTXtMi/bfZ4Z9rX/RdiXYV4wdUOvHQJNG96JMY0iRhQghhmTDzAVz3eLcU5S87KmCs1sEZ3aN/Bc7IeDVhD0iEjvyPyzd/2tBhJJchXT+hg4bwDa4rKvYxSKuAbKwvGW/Z5DPF1lRJow7002jB4T2SWWV9cWpcQQp/CfBmvPd63zLV+rldfGsIYFfTwcSD9SsYRYlTO9a7H7v21lQ5eYPTAC8xoqDX6AiLMSUCxintWM4D730hrbnxJiDC1PE0504Cg/BJ+SVQ== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Zhang Peng Currently we flush TLB for every dirty folio, which is a bottleneck for systems with many cores as this causes heavy IPI usage. So instead, batch the folios, and flush once for every 31 folios (one folio_batch). These folios will be held in a folio_batch releasing their lock, then when folio_batch is full, do following steps: - For each folio: lock - check still evictable (writeback, lru, mapped, dma_pinned) - If no longer evictable, put back to LRU - Flush TLB once for the batch - Pageout the folios Note we can't hold a frozen folio in folio_batch for long as it will cause filemap/swapcache lookup to livelock. Fortunately pageout usually won't take too long; sync IO is fast, and non-sync IO will be issued with the folio marked writeback. Suggested-by: Kairui Song Signed-off-by: Zhang Peng --- mm/vmscan.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 62 insertions(+), 7 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 63cc88c875e8..27de8034f582 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1217,6 +1217,47 @@ static void pageout_one(struct folio *folio, struct list_head *ret_folios, folio_test_unevictable(folio), folio); } +static void pageout_batch(struct folio_batch *fbatch, + struct list_head *ret_folios, + struct folio_batch *free_folios, + struct scan_control *sc, struct reclaim_stat *stat, + struct swap_iocb **plug, struct list_head *folio_list) +{ + int i, count = folio_batch_count(fbatch); + struct folio *folio; + + folio_batch_reinit(fbatch); + for (i = 0; i < count; ++i) { + folio = fbatch->folios[i]; + if (!folio_trylock(folio)) { + list_add(&folio->lru, ret_folios); + continue; + } + + if (folio_test_writeback(folio) || folio_test_lru(folio) || + folio_mapped(folio) || folio_maybe_dma_pinned(folio)) { + folio_unlock(folio); + list_add(&folio->lru, ret_folios); + continue; + } + + folio_batch_add(fbatch, folio); + } + + i = 0; + count = folio_batch_count(fbatch); + if (!count) + return; + /* One TLB flush for the batch */ + try_to_unmap_flush_dirty(); + for (i = 0; i < count; ++i) { + folio = fbatch->folios[i]; + pageout_one(folio, ret_folios, free_folios, sc, stat, plug, + folio_list); + } + folio_batch_reinit(fbatch); +} + static bool folio_try_unmap(struct folio *folio, struct reclaim_stat *stat, unsigned int nr_pages) { @@ -1264,6 +1305,8 @@ static void shrink_folio_list(struct list_head *folio_list, struct mem_cgroup *memcg) { struct folio_batch free_folios; + struct folio_batch flush_folios; + LIST_HEAD(ret_folios); LIST_HEAD(demote_folios); unsigned int nr_demoted = 0; @@ -1272,6 +1315,8 @@ static void shrink_folio_list(struct list_head *folio_list, struct swap_iocb *plug = NULL; folio_batch_init(&free_folios); + folio_batch_init(&flush_folios); + memset(stat, 0, sizeof(*stat)); cond_resched(); do_demote_pass = can_demote(pgdat->node_id, sc, memcg); @@ -1565,15 +1610,21 @@ static void shrink_folio_list(struct list_head *folio_list, goto keep_locked; if (!sc->may_writepage) goto keep_locked; - /* - * Folio is dirty. Flush the TLB if a writable entry - * potentially exists to avoid CPU writes after I/O - * starts and then write it out here. + * For anon, we should only see swap cache (anon) and + * the list pinning the page. For file page, the filemap + * and the list pins it. The folio is unlocked while + * held in the batch, so pageout_batch() relocks each + * folio and rechecks its state. If the folio is under + * writeback, on LRU, mapped, or DMA-pinned, it will + * not be written out and is put back to LRU list. */ - try_to_unmap_flush_dirty(); - pageout_one(folio, &ret_folios, &free_folios, sc, stat, - &plug, folio_list); + folio_unlock(folio); + if (!folio_batch_add(&flush_folios, folio)) + pageout_batch(&flush_folios, + &ret_folios, &free_folios, + sc, stat, &plug, + folio_list); goto next; } @@ -1603,6 +1654,10 @@ static void shrink_folio_list(struct list_head *folio_list, next: continue; } + if (folio_batch_count(&flush_folios)) { + pageout_batch(&flush_folios, &ret_folios, &free_folios, sc, + stat, &plug, folio_list); + } /* 'folio_list' is always empty here */ /* Migrate folios selected for demotion */ -- 2.43.7