Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 9b3398c3 authored by Huang Jianan's avatar Huang Jianan Committed by Gao Xiang
Browse files

erofs: use sync decompression for atomic contexts only 

Sync decompression was introduced to get rid of additional kworker
scheduling overhead. But there is no such overhead in non-atomic
contexts. Therefore, it should be better to turn off sync decompression
to avoid the current thread waiting in z_erofs_runqueue.

Link: https://lore.kernel.org/r/20210317035448.13921-3-huangjianan@oppo.com


Reviewed-by: default avatarGao Xiang <hsiangkao@redhat.com>
Reviewed-by: default avatarChao Yu <yuchao0@huawei.com>
Signed-off-by: default avatarHuang Jianan <huangjianan@oppo.com>
Signed-off-by: default avatarGuo Weichao <guoweichao@oppo.com>
Signed-off-by: default avatarGao Xiang <hsiangkao@redhat.com>
parent 076924e0

fs/erofs/internal.h

+3 −0
Original line number Diff line number Diff line
@@ -54,6 +54,9 @@ struct erofs_sb_info { 
	/* the dedicated workstation for compression */

	struct radix_tree_root workstn_tree;



	/* strategy of sync decompression (false - auto, true - force on) */

	bool readahead_sync_decompress;



	/* threshold for decompression synchronously */

	unsigned int max_sync_decompress_pages;

fs/erofs/super.c

+1 −0
Original line number Diff line number Diff line
@@ -239,6 +239,7 @@ static void erofs_default_options(struct erofs_sb_info *sbi) 
#ifdef CONFIG_EROFS_FS_ZIP

	sbi->cache_strategy = EROFS_ZIP_CACHE_READAROUND;

	sbi->max_sync_decompress_pages = 3;

	sbi->readahead_sync_decompress = false;

#endif

#ifdef CONFIG_EROFS_FS_XATTR

	set_opt(sbi, XATTR_USER);

fs/erofs/zdata.c

+6 −2
Original line number Diff line number Diff line
@@ -712,6 +712,8 @@ static void z_erofs_decompressqueue_work(struct work_struct *work); 
static void z_erofs_decompress_kickoff(struct z_erofs_decompressqueue *io,

				       bool sync, int bios)

{

	struct erofs_sb_info *const sbi = EROFS_SB(io->sb);



	/* wake up the caller thread for sync decompression */

	if (sync) {

		unsigned long flags;
@@ -725,9 +727,10 @@ static void z_erofs_decompress_kickoff(struct z_erofs_decompressqueue *io, 


	if (atomic_add_return(bios, &io->pending_bios))

		return;

	/* Use workqueue decompression for atomic contexts only */

	/* Use workqueue and sync decompression for atomic contexts only */

	if (in_atomic() || irqs_disabled()) {

		queue_work(z_erofs_workqueue, &io->u.work);

		sbi->readahead_sync_decompress = true;

		return;

	}

	z_erofs_decompressqueue_work(&io->u.work);
@@ -1341,7 +1344,8 @@ static int z_erofs_readpages(struct file *filp, struct address_space *mapping, 
	struct inode *const inode = mapping->host;

	struct erofs_sb_info *const sbi = EROFS_I_SB(inode);



	bool sync = (nr_pages <= sbi->max_sync_decompress_pages);

	bool sync = (sbi->readahead_sync_decompress &&

			nr_pages <= sbi->max_sync_decompress_pages);

	struct z_erofs_decompress_frontend f = DECOMPRESS_FRONTEND_INIT(inode);

	gfp_t gfp = mapping_gfp_constraint(mapping, GFP_KERNEL);

	struct page *head = NULL;