From a8efc69a65fbef61bed0923c0de3425d74817c1c Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 13 Jul 2026 11:33:38 +0200 Subject: [PATCH] shmem: provide a shmem_write_folio wrapper Patch series "better block swap batching and a different take on swap_ops v5". This series makes use of the swap_iocb for block as well so that it doesn't do inefficient single-bio I/O, and then rebases the swap_ops from Baoquan on top of the now very different method structure. When running doing kernels builds, which is a workload that doesn't really do much THP anonymous memory it still gets 2x clustering for writeout and 1.2x for reading back swap in. The overall times do not actually change, though. This patch (of 7): Provide a wrapper for the shmem abuses in drm to prepare for swap I/O refactoring by keeping swap_iocb handling entirely contained in mm/. Link: https://lore.kernel.org/20260713093350.2154226-1-hch@lst.de Link: https://lore.kernel.org/20260713093350.2154226-2-hch@lst.de Signed-off-by: Christoph Hellwig Reviewed-by: Baoquan He Reviewed-by: Nhat Pham Reviewed-by: Baolin Wang Acked-by: Chris Li Reviewed-by: Kairui Song Cc: Kemeng Shi Cc: Barry Song Cc: Youngjun Park Signed-off-by: Andrew Morton --- drivers/gpu/drm/i915/gem/i915_gem_shmem.c | 2 +- drivers/gpu/drm/ttm/ttm_backup.c | 2 +- include/linux/shmem_fs.h | 5 +---- mm/shmem.c | 7 ++++++- mm/swap.h | 4 ++++ 5 files changed, 13 insertions(+), 7 deletions(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c index 06543ae60706..ef9440166295 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c @@ -325,7 +325,7 @@ void __shmem_writeback(size_t size, struct address_space *mapping) if (folio_mapped(folio)) folio_redirty_for_writepage(&wbc, folio); else - error = shmem_writeout(folio, NULL, NULL); + error = shmem_write_folio(folio); } } diff --git a/drivers/gpu/drm/ttm/ttm_backup.c b/drivers/gpu/drm/ttm/ttm_backup.c index 3c067aadc52d..0c2d53a13b2a 100644 --- a/drivers/gpu/drm/ttm/ttm_backup.c +++ b/drivers/gpu/drm/ttm/ttm_backup.c @@ -160,7 +160,7 @@ ttm_backup_backup_folio(struct file *backup, struct folio *folio, if (writeback && !folio_mapped(to_folio) && folio_clear_dirty_for_io(to_folio)) { folio_set_reclaim(to_folio); - ret = shmem_writeout(to_folio, NULL, NULL); + ret = shmem_write_folio(to_folio); if (!folio_test_writeback(to_folio)) folio_clear_reclaim(to_folio); if (ret == AOP_WRITEPAGE_ACTIVATE) diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h index e729b9b0e38d..5663dff53186 100644 --- a/include/linux/shmem_fs.h +++ b/include/linux/shmem_fs.h @@ -12,8 +12,6 @@ #include #include -struct swap_iocb; - /* inode in-kernel data */ #ifdef CONFIG_TMPFS_QUOTA @@ -123,8 +121,7 @@ static inline bool shmem_mapping(const struct address_space *mapping) void shmem_unlock_mapping(struct address_space *mapping); struct page *shmem_read_mapping_page_gfp(struct address_space *mapping, pgoff_t index, gfp_t gfp_mask); -int shmem_writeout(struct folio *folio, struct swap_iocb **plug, - struct list_head *folio_list); +int shmem_write_folio(struct folio *folio); void shmem_truncate_range(struct inode *inode, loff_t start, uoff_t end); int shmem_unuse(unsigned int type); diff --git a/mm/shmem.c b/mm/shmem.c index 8ea776e52823..d245e01416e9 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1751,7 +1751,12 @@ int shmem_writeout(struct folio *folio, struct swap_iocb **plug, folio_mark_dirty(folio); return AOP_WRITEPAGE_ACTIVATE; /* Return with folio locked */ } -EXPORT_SYMBOL_GPL(shmem_writeout); + +int shmem_write_folio(struct folio *folio) +{ + return shmem_writeout(folio, NULL, NULL); +} +EXPORT_SYMBOL_GPL(shmem_write_folio); #if defined(CONFIG_NUMA) && defined(CONFIG_TMPFS) static void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol) diff --git a/mm/swap.h b/mm/swap.h index 4e4c291bbfde..276b7975a9dc 100644 --- a/mm/swap.h +++ b/mm/swap.h @@ -486,4 +486,8 @@ static inline unsigned int folio_swap_flags(struct folio *folio) } #endif /* CONFIG_SWAP */ + +int shmem_writeout(struct folio *folio, struct swap_iocb **plug, + struct list_head *folio_list); + #endif /* _MM_SWAP_H */