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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=3652; i=zippermonkey@icloud.com; s=20260309; h=from:subject:message-id; bh=1S4mtwiSgiEXK9RkHO0cUF3Km1aYqH6AUACfPgCXzzs=; b=KII/Mz4IcW3cMukofh+i+NVuXjEc0BO0JHhh5A1sDytP0Cf3RYIPWe0CLAY53vYquY3Rvrm3f CyS6TrAdROnCEbMdP2P8gbzLEHo39VJ4cyTKYFkwNnITM8mITHaXPN/ X-Developer-Key: i=zippermonkey@icloud.com; a=ed25519; pk=tPCLpFnBfIyHsp0k7eaUTUREEa36bQNW/69X+NS8wBU= X-Proofpoint-GUID: L7-WM3VWRO91kEFUKdWNbdySIh1JRmtt X-Authority-Info-Out: v=2.4 cv=acpsXBot c=1 sm=1 tr=0 ts=69c4f013 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=VwQbUJbxAAAA:8 a=v3ZZPjhaAAAA:8 a=GvQkQWPkAAAA:8 a=0nsp5VSLLG1NfpzbPScA:9 a=QEXdDO2ut3YA:10 a=J82S1U87d15UFHHUFZS8:22 a=yLjSXO_LiVxs9JEHLWbQ:22 X-Proofpoint-ORIG-GUID: L7-WM3VWRO91kEFUKdWNbdySIh1JRmtt X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMzI2MDA2MiBTYWx0ZWRfX/FdBr0XUBu41 S2ZG2gL9rXdB+umYDZHE+B0BX51f6m9xwVz8LAby84CmttAeWrm9wTTm4uJdQU8Vb3YwjOZ1sPY PlK48RjYy30dUY8gZMm9koj2Oihg9qpwMBmUu6Y3gCNQnOqxgFSXKAokxzcOMCinj6PrTNpf70x ktXMhhxoPtEzUOd6avg3UNEUhlhYfpn9IiZemU55dKorv05zKauSM+tx/8f0dKLdCHeHYR6UqsN v3zXhojUk39UiuyJTwpnGdquzElLpMuYPQph5HCqGPJMoboVauYPQFVgXILOAafiUgtV0k5f0uf SqdhzW5xJWyjYHrmoIaiLpzjHqFxXziSMCS2J7pV5ETSajYFF5kZUuhDGBrGLc= 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 bulkscore=0 mlxlogscore=999 phishscore=0 spamscore=0 clxscore=1015 mlxscore=0 malwarescore=0 suspectscore=0 adultscore=0 lowpriorityscore=0 classifier=spam authscore=0 adjust=0 reason=mlx scancount=1 engine=8.22.0-2601150000 definitions=main-2603260062 X-Rspamd-Queue-Id: E88721C0015 X-Stat-Signature: xpy9bq8qgoj3x95upuq6j8ojap9ddykm X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1774514196-854229 X-HE-Meta: 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 4tmBRdZg 2HzTxH/HIwaNPnoZ875WUMVEpsp9jSb84BlfhSQhrX+HNAK6tTRwhVN57hIafGwM1WFPhpN7VmM0mRafujloH7bfuEzxxHPKexiQ/M8huwp4OvDnaxlAjCYGnsYfC376a1mWmKsNts9ERvqZaKXIklRowPOmnzUiAi3zIh45zy9D/7eHlrFON8BXDsVIIF5GJR8ENoFtgrM75V8AY99eQIJrwLwW5LOuPXy6PsddeOIsUALMutmPLM1zqWZVSjfu1loreK3sc5swtJKhWSt2jm5tKRwMt9Ao52m+zc/9jsUTF8pd8H/RpVsHADOQYu2115M542h4UW5YZS4sDvJoBA3ZYY2353Kl75r8WvuJybgQRSCA005xXqGLZP6WERxjz5CfUmtGojBADXQTKbwEUD75Tl8DTdOKHBsDgFUyVkep0QcgAmQ48kxZZB42oPT09Sqr9 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: This series introduces batch TLB flushing optimization for dirty folios during memory reclaim, aiming to reduce IPI overhead on multi-core systems. Background ---------- Currently, when performing pageout in memory reclaim, try_to_unmap_flush_dirty() is called for each dirty folio individually. On multi-core systems, this causes frequent IPIs which can significantly impact performance. Approach -------- This patch series accumulates dirty folios into batches and performs a single TLB flush for the entire batch, rather than flushing for each individual folio. Changes ------- Patch 1: Add nr_reclaimed to reclaim_stat so shrink_folio_list() can be changed to void, giving a consistent interface where all per-pass statistics are reported through reclaim_stat. Patch 2: Extract the folio activation block at activate_locked into folio_active_bounce(). Patch 3: Extract the pageout() dispatch state machine and the folio-freeing path into pageout_one() and folio_free() respectively. Patch 4: Extract the TTU setup and try_to_unmap() block into folio_try_unmap(). Patch 5: Implement batch TLB flushing logic. Dirty folios are accumulated in batches and a single TLB flush is performed for each batch before calling pageout. Testing ------- The benchmark script uses stress-ng to compare TLB shootdown behavior before and after this patch. It constrains a stress-ng workload via memcg to force reclaim through shrink_folio_list(), reporting TLB shootdowns and IPIs. Core benchmark command: stress-ng --vm 16 --vm-bytes 2G --vm-keep --timeout 60 ========================================================================== batch_dirty_tlb_flush Benchmark Results ========================================================================== Kernel: 7.0.0-rc1+ CPUs: 16 MemTotal: 31834M SwapTotal: 8191M memcg limit: 512M alloc: 2G workers: 16 duration: 60s -------------------------------------------------------------------------- Metric Before After Delta (abs / %) -------------------------------------------------------------------------- bogo ops/s 28238.63 35833.97 +7595.34 (+26.9%) TLB shootdowns 55428953 17621697 -37807256 (-68.2%) Function call IPIs 34073695 14498768 -19574927 (-57.4%) pgscan_anon (pages) 52856224 60252894 7396670 (+14.0%) pgsteal_anon (pages) 29004962 34054753 5049791 (+17.4%) -------------------------------------------------------------------------- Suggested-by: Kairui Song Signed-off-by: Zhang Peng --- Changes in v2: - Fix incorrect comment about page_ref_freeze - Add folio_maybe_dma_pinned() check in pageout_batch() - Link to v1: https://lore.kernel.org/r/20260309-batch-tlb-flush-v1-0-eb8fed7d1a9e@icloud.com --- Zhang Peng (5): mm/vmscan: track reclaimed pages in reclaim_stat mm/vmscan: extract folio activation into folio_active_bounce() mm/vmscan: extract folio_free() and pageout_one() mm/vmscan: extract folio unmap logic into folio_try_unmap() mm/vmscan: flush TLB for every 31 folios evictions include/linux/vmstat.h | 1 + mm/vmscan.c | 456 +++++++++++++++++++++++++++++++------------------ 2 files changed, 287 insertions(+), 170 deletions(-) --- base-commit: 7c5507fca017a80ece36f34e36c77e2bee267517 change-id: 20260309-batch-tlb-flush-893f0e56b496 Best regards, -- Zhang Peng