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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=1773044270; l=4427; i=zippermonkey@icloud.com; s=20260309; h=from:subject:message-id; bh=VtbVoUdutucQYTv61lHy5DXkSCu6zJZpJudQ30ChVHA=; b=hb84Un+QVXegPOTad/271FdH2TnK0FCOWCwyQrjIcYqmfgBJ2uz0HVL0r8lRGfBXbWq4q5Q3B MJJHWQGILuwAzFjHJquHifaJ+c6i/rVn/faJo05uEQWnci0nAx0TqPg X-Developer-Key: i=zippermonkey@icloud.com; a=ed25519; pk=tPCLpFnBfIyHsp0k7eaUTUREEa36bQNW/69X+NS8wBU= X-Endpoint-Received: by B4 Relay for zippermonkey@icloud.com/20260309 with auth_id=671 X-Original-From: Zhang Peng Reply-To: zippermonkey@icloud.com X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: D6D39100005 X-Stat-Signature: p1bcqda13ysqwpjtmt8ggi31t663rgwq X-Rspam-User: X-HE-Tag: 1773044278-966393 X-HE-Meta: U2FsdGVkX19DWnpmHV85HWJt+7S/3NsdShFj4q4MGQjcPevsxp9lfGiEwtG0RbKi5ik8j4pMglIKanN0ZI6HrRAZoZupwzu32UXg5vL7yjSw7lG0lP2o4Abn0X58tlzrh9FVoai7gShPF6hg58YmcZp1n6wHB44LHE2v5y+Nw1C5x+b1v0FQ/tAn8QsIcL2dESEFV3hI5zxVyw5Y+EnXZ2ATtCOsPVUMkvaony/28rwdU6wvi7pKy5FGRjemM9ZxyVv7AD/Vou8aZv9eANaVXYbSafApYH+rOlMg+YCQC/Uvg/EOw7eYjOOg+07fs+aRosl/d0K3sq21CaYaAHdK4PF8lNLoBNQjOBQlSz84Iy4NyYRkYwDDQ7fjyG6xuUA/UEkmeXWgZeDY7mls0ueO3KmRFGB4B8l0mZ3YLv7WqOFXPK3fM8nOKN0f1n1Epd9fU+W2uDGVPOKGb4wvqAMxkn4Pktbm2guVS9fB/zkvggk8RCSdrp0StC6eMXUy/2ZlJsKaLrHizcAJz/UuyKIqTs620doZk6J9EpL864/CT1gZjNzlKa+9kJ1YRpbdGjwc0c+2ZR3EPADB2D9RSayTlEHlTHuJeEmeCPYCYWz4WY6Clgxgc9tOO3u3mUDpRt94etH0mBd3wSi3yxGl++g6jjDR3jCkulKsxkrCkP+DWYWr8SXS4g26nMuZPpOiZfMHAvYUk46l8p+U0lBCmh3uaySOIuLVNVdXv24blOSt1oQ3tir6Y6s4wKvHrlstMNcz7m9IoCr3A1p2Kn0ONNbuHKIGu3d2bee5XKkqxEYpJe3MDaMxAr1LRghygwz9XfWxd48Mvph5zS9A/mquz0WA9oqTYaUTEOcRUNVUJFuk2xeroG4APrtE+g/jgDe+aNSrZ1w8TJZB/fhq4Zo8ao792fbeTZd8X60CzMJ0ZNr/kz/PpriJBoIm7g2Q7ywwZQ5Zk4P9bs8nZCISutdbit5 0QmqhpwL 2xP6rUbxgWyoa1b+x9+NkCzr9YIvSUA6Zdfn7ja0OaU8tkMzLedmgJjgJXtex+3dushPPvJuR8pUcH3sLs4xXePX0/vEti5zCInMbzPIfWEoeuUdcbEPiSwR0d6Kf2omZZo818uBIr/7yzcCpU0brpQn9NUnZHMo5DjfIvWqUEh51LKBxkh/lJNpNYauXmevWg7wx0Nhk4qGFrUTwTgkB4LU5fNl989/5cDsr33gDwj5H993dDgbX16vzAhUIpLXylrXSzH6O76H5ezh2YT0mozEA6Rvp2G5+HC5AIYXcFEGmOWEKfaGV6ma+eybNmFWGB243V2vAYPXQ0DnIt+okfY0ONj0mwA7WlciO+HMKy8MyKRh68pBDIA769px/Wc90F864QHZuquxC3c4= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: bruzzhang 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 - unlock - If no longer evictable, return the folio to the caller. - Flush TLB once for the batch - Pageout the folios (refcount freeze happens in the pageout path) 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: bruzzhang --- mm/vmscan.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 61 insertions(+), 7 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index a336f7fc7dae..69cdd3252ff8 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1240,6 +1240,48 @@ static void pageout_one(struct folio *folio, struct list_head *ret_folios, VM_BUG_ON_FOLIO(folio_test_lru(folio) || 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 = 0, count = folio_batch_count(fbatch); + struct folio *folio; + + folio_batch_reinit(fbatch); + do { + 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)) + goto next; + folio_batch_add(fbatch, folio); + continue; +next: + folio_unlock(folio); + list_add(&folio->lru, ret_folios); + } while (++i != count); + + i = 0; + count = folio_batch_count(fbatch); + if (!count) + return; + /* One TLB flush for the batch */ + try_to_unmap_flush_dirty(); + do { + folio = fbatch->folios[i]; + pageout_one(folio, ret_folios, free_folios, sc, stat, plug, + folio_list); + } while (++i != count); + folio_batch_reinit(fbatch); +} + /* * Reclaimed folios are counted in stat->nr_reclaimed. */ @@ -1249,6 +1291,8 @@ 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; @@ -1257,6 +1301,8 @@ 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); @@ -1578,15 +1624,19 @@ 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. Combined with the page_ref_freeze + * in pageout_batch ensure nothing else touches the page + * during lock unlocked. */ - 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; } @@ -1614,6 +1664,10 @@ 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