From 40452ffca3c1a0f2994e826f9fa213b107f1a2d4 Mon Sep 17 00:00:00 2001 From: Huang Jianan Date: Mon, 6 Dec 2021 22:35:52 +0800 Subject: [PATCH] erofs: add sysfs node to control sync decompression strategy Although readpage is a synchronous path, there will be no additional kworker scheduling overhead in non-atomic contexts together with dm-verity. Let's add a sysfs node to disable sync decompression as an option. Link: https://lore.kernel.org/r/20211206143552.8384-1-huangjianan@oppo.com Reviewed-by: Chao Yu Signed-off-by: Huang Jianan Signed-off-by: Gao Xiang --- Documentation/ABI/testing/sysfs-fs-erofs | 9 ++++++++ fs/erofs/internal.h | 10 +++++++-- fs/erofs/super.c | 2 +- fs/erofs/sysfs.c | 15 ++++++++++++++ fs/erofs/zdata.c | 26 ++++++++++++++++++++---- 5 files changed, 55 insertions(+), 7 deletions(-) diff --git a/Documentation/ABI/testing/sysfs-fs-erofs b/Documentation/ABI/testing/sysfs-fs-erofs index a9512594dc4c..05482374a741 100644 --- a/Documentation/ABI/testing/sysfs-fs-erofs +++ b/Documentation/ABI/testing/sysfs-fs-erofs @@ -5,3 +5,12 @@ Description: Shows all enabled kernel features. Supported features: zero_padding, compr_cfgs, big_pcluster, chunked_file, device_table, compr_head2, sb_chksum. + +What: /sys/fs/erofs//sync_decompress +Date: November 2021 +Contact: "Huang Jianan" +Description: Control strategy of sync decompression + - 0 (default, auto): enable for readpage, and enable for + readahead on atomic contexts only, + - 1 (force on): enable for readpage and readahead. + - 2 (force off): disable for all situations. diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h index 43f0332fa489..8e70435629e5 100644 --- a/fs/erofs/internal.h +++ b/fs/erofs/internal.h @@ -56,12 +56,18 @@ struct erofs_device_info { u32 mapped_blkaddr; }; +enum { + EROFS_SYNC_DECOMPRESS_AUTO, + EROFS_SYNC_DECOMPRESS_FORCE_ON, + EROFS_SYNC_DECOMPRESS_FORCE_OFF +}; + struct erofs_mount_opts { #ifdef CONFIG_EROFS_FS_ZIP /* current strategy of how to use managed cache */ unsigned char cache_strategy; - /* strategy of sync decompression (false - auto, true - force on) */ - bool readahead_sync_decompress; + /* strategy of sync decompression (0 - auto, 1 - force on, 2 - force off) */ + unsigned int sync_decompress; /* threshold for decompression synchronously */ unsigned int max_sync_decompress_pages; diff --git a/fs/erofs/super.c b/fs/erofs/super.c index abc1da5d1719..58f381f80205 100644 --- a/fs/erofs/super.c +++ b/fs/erofs/super.c @@ -423,7 +423,7 @@ static void erofs_default_options(struct erofs_fs_context *ctx) #ifdef CONFIG_EROFS_FS_ZIP ctx->opt.cache_strategy = EROFS_ZIP_CACHE_READAROUND; ctx->opt.max_sync_decompress_pages = 3; - ctx->opt.readahead_sync_decompress = false; + ctx->opt.sync_decompress = EROFS_SYNC_DECOMPRESS_AUTO; #endif #ifdef CONFIG_EROFS_FS_XATTR set_opt(&ctx->opt, XATTR_USER); diff --git a/fs/erofs/sysfs.c b/fs/erofs/sysfs.c index 33e15fa63c82..666693432107 100644 --- a/fs/erofs/sysfs.c +++ b/fs/erofs/sysfs.c @@ -16,6 +16,7 @@ enum { enum { struct_erofs_sb_info, + struct_erofs_mount_opts, }; struct erofs_attr { @@ -54,7 +55,14 @@ static struct erofs_attr erofs_attr_##_name = { \ #define ATTR_LIST(name) (&erofs_attr_##name.attr) +#ifdef CONFIG_EROFS_FS_ZIP +EROFS_ATTR_RW_UI(sync_decompress, erofs_mount_opts); +#endif + static struct attribute *erofs_attrs[] = { +#ifdef CONFIG_EROFS_FS_ZIP + ATTR_LIST(sync_decompress), +#endif NULL, }; ATTRIBUTE_GROUPS(erofs); @@ -85,6 +93,8 @@ static unsigned char *__struct_ptr(struct erofs_sb_info *sbi, { if (struct_type == struct_erofs_sb_info) return (unsigned char *)sbi + offset; + if (struct_type == struct_erofs_mount_opts) + return (unsigned char *)&sbi->opt + offset; return NULL; } @@ -130,6 +140,11 @@ static ssize_t erofs_attr_store(struct kobject *kobj, struct attribute *attr, return ret; if (t != (unsigned int)t) return -ERANGE; +#ifdef CONFIG_EROFS_FS_ZIP + if (!strcmp(a->attr.name, "sync_decompress") && + (t > EROFS_SYNC_DECOMPRESS_FORCE_OFF)) + return -EINVAL; +#endif *(unsigned int *)ptr = t; return len; case attr_pointer_bool: diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c index 9a249bfc2770..bc765d8a6dc2 100644 --- a/fs/erofs/zdata.c +++ b/fs/erofs/zdata.c @@ -762,6 +762,21 @@ err_out: goto out; } +static bool z_erofs_get_sync_decompress_policy(struct erofs_sb_info *sbi, + unsigned int readahead_pages) +{ + /* auto: enable for readpage, disable for readahead */ + if ((sbi->opt.sync_decompress == EROFS_SYNC_DECOMPRESS_AUTO) && + !readahead_pages) + return true; + + if ((sbi->opt.sync_decompress == EROFS_SYNC_DECOMPRESS_FORCE_ON) && + (readahead_pages <= sbi->opt.max_sync_decompress_pages)) + return true; + + return false; +} + 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) @@ -784,7 +799,9 @@ static void z_erofs_decompress_kickoff(struct z_erofs_decompressqueue *io, /* Use workqueue and sync decompression for atomic contexts only */ if (in_atomic() || irqs_disabled()) { queue_work(z_erofs_workqueue, &io->u.work); - sbi->opt.readahead_sync_decompress = true; + /* enable sync decompression for readahead */ + if (sbi->opt.sync_decompress == EROFS_SYNC_DECOMPRESS_AUTO) + sbi->opt.sync_decompress = EROFS_SYNC_DECOMPRESS_FORCE_ON; return; } z_erofs_decompressqueue_work(&io->u.work); @@ -1435,6 +1452,7 @@ skip: static int z_erofs_readpage(struct file *file, struct page *page) { struct inode *const inode = page->mapping->host; + struct erofs_sb_info *const sbi = EROFS_I_SB(inode); struct z_erofs_decompress_frontend f = DECOMPRESS_FRONTEND_INIT(inode); struct page *pagepool = NULL; int err; @@ -1450,7 +1468,8 @@ static int z_erofs_readpage(struct file *file, struct page *page) (void)z_erofs_collector_end(&f.clt); /* if some compressed cluster ready, need submit them anyway */ - z_erofs_runqueue(inode->i_sb, &f, &pagepool, true); + z_erofs_runqueue(inode->i_sb, &f, &pagepool, + z_erofs_get_sync_decompress_policy(sbi, 0)); if (err) erofs_err(inode->i_sb, "failed to read, err [%d]", err); @@ -1501,8 +1520,7 @@ static void z_erofs_readahead(struct readahead_control *rac) (void)z_erofs_collector_end(&f.clt); z_erofs_runqueue(inode->i_sb, &f, &pagepool, - sbi->opt.readahead_sync_decompress && - nr_pages <= sbi->opt.max_sync_decompress_pages); + z_erofs_get_sync_decompress_policy(sbi, nr_pages)); if (f.map.mpage) put_page(f.map.mpage); erofs_release_pages(&pagepool);