From d87f639258a6a5980183f11876c884931ad93da2 Mon Sep 17 00:00:00 2001 From: Roman Gushchin Date: Fri, 28 Feb 2020 16:14:11 -0800 Subject: ext4: use non-movable memory for superblock readahead Since commit a8ac900b8163 ("ext4: use non-movable memory for the superblock") buffers for ext4 superblock were allocated using the sb_bread_unmovable() helper which allocated buffer heads out of non-movable memory blocks. It was necessarily to not block page migrations and do not cause cma allocation failures. However commit 85c8f176a611 ("ext4: preload block group descriptors") broke this by introducing pre-reading of the ext4 superblock. The problem is that __breadahead() is using __getblk() underneath, which allocates buffer heads out of movable memory. It resulted in page migration failures I've seen on a machine with an ext4 partition and a preallocated cma area. Fix this by introducing sb_breadahead_unmovable() and __breadahead_gfp() helpers which use non-movable memory for buffer head allocations and use them for the ext4 superblock readahead. Reviewed-by: Andreas Dilger Fixes: 85c8f176a611 ("ext4: preload block group descriptors") Signed-off-by: Roman Gushchin Link: https://lore.kernel.org/r/20200229001411.128010-1-guro@fb.com Signed-off-by: Theodore Ts'o --- fs/buffer.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'fs/buffer.c') diff --git a/fs/buffer.c b/fs/buffer.c index f73276d746bb..599a0bf7257b 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -1371,6 +1371,17 @@ void __breadahead(struct block_device *bdev, sector_t block, unsigned size) } EXPORT_SYMBOL(__breadahead); +void __breadahead_gfp(struct block_device *bdev, sector_t block, unsigned size, + gfp_t gfp) +{ + struct buffer_head *bh = __getblk_gfp(bdev, block, size, gfp); + if (likely(bh)) { + ll_rw_block(REQ_OP_READ, REQ_RAHEAD, 1, &bh); + brelse(bh); + } +} +EXPORT_SYMBOL(__breadahead_gfp); + /** * __bread_gfp() - reads a specified block and returns the bh * @bdev: the block_device to read from -- cgit v1.2.3 From c4b4c2a78a9fc0c532c58504e8cb5441224ff1d9 Mon Sep 17 00:00:00 2001 From: Zhiqiang Liu Date: Mon, 13 Apr 2020 13:12:10 +0800 Subject: buffer: remove useless comment and WB_REASON_FREE_MORE_MEM, reason. free_more_memory func has been completely removed in commit bc48f001de12 ("buffer: eliminate the need to call free_more_memory() in __getblk_slow()") So comment and `WB_REASON_FREE_MORE_MEM` reason about free_more_memory are no longer needed. Fixes: bc48f001de12 ("buffer: eliminate the need to call free_more_memory() in __getblk_slow()") Reviewed-by: Jan Kara Signed-off-by: Zhiqiang Liu Signed-off-by: Jens Axboe --- fs/buffer.c | 2 +- include/linux/backing-dev-defs.h | 1 - include/trace/events/writeback.h | 1 - 3 files changed, 1 insertion(+), 3 deletions(-) (limited to 'fs/buffer.c') diff --git a/fs/buffer.c b/fs/buffer.c index f73276d746bb..763de99508de 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -967,7 +967,7 @@ grow_dev_page(struct block_device *bdev, sector_t block, struct page *page; struct buffer_head *bh; sector_t end_block; - int ret = 0; /* Will call free_more_memory() */ + int ret = 0; gfp_t gfp_mask; gfp_mask = mapping_gfp_constraint(inode->i_mapping, ~__GFP_FS) | gfp; diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h index 4fc87dee005a..ee577a83cfe6 100644 --- a/include/linux/backing-dev-defs.h +++ b/include/linux/backing-dev-defs.h @@ -54,7 +54,6 @@ enum wb_reason { WB_REASON_SYNC, WB_REASON_PERIODIC, WB_REASON_LAPTOP_TIMER, - WB_REASON_FREE_MORE_MEM, WB_REASON_FS_FREE_SPACE, /* * There is no bdi forker thread any more and works are done diff --git a/include/trace/events/writeback.h b/include/trace/events/writeback.h index d94def25e4dc..85a33bea76f1 100644 --- a/include/trace/events/writeback.h +++ b/include/trace/events/writeback.h @@ -36,7 +36,6 @@ EM( WB_REASON_SYNC, "sync") \ EM( WB_REASON_PERIODIC, "periodic") \ EM( WB_REASON_LAPTOP_TIMER, "laptop_timer") \ - EM( WB_REASON_FREE_MORE_MEM, "free_more_memory") \ EM( WB_REASON_FS_FREE_SPACE, "fs_free_space") \ EMe(WB_REASON_FORKER_THREAD, "forker_thread") -- cgit v1.2.3