Commit cc831ab3 authored by Gao Xiang's avatar Gao Xiang
Browse files

erofs: tidy up synchronous decompression 



 - Get rid of `sbi->opt.max_sync_decompress_pages` since it's fixed as
   3 all the time;

 - Add Z_EROFS_MAX_SYNC_DECOMPRESS_BYTES in bytes instead of in pages,
   since for non-4K pages, 3-page limitation makes no sense;

 - Move `sync_decompress` to sbi to avoid unexpected remount impact;

 - Fold z_erofs_is_sync_decompress() into its caller;

 - Better description of sysfs entry `sync_decompress`.

Reviewed-by: default avatarChao Yu <chao@kernel.org>
Signed-off-by: default avatarGao Xiang <hsiangkao@linux.alibaba.com>
parent 06e5c340

Documentation/ABI/testing/sysfs-fs-erofs

+9 −5
Original line number Diff line number Diff line
@@ -10,12 +10,16 @@ Description: Shows all enabled kernel features. 
What:		/sys/fs/erofs/<disk>/sync_decompress

Date:		November 2021

Contact:	"Huang Jianan" <huangjianan@oppo.com>

Description:	Control strategy of sync decompression:

Description:	Control strategy of synchronous decompression. Synchronous

		decompression tries to decompress in the reader thread for

		synchronous reads and small asynchronous reads (<= 12 KiB):



		- 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.

		- 0 (auto, default): apply to synchronous reads only, but will

		                     switch to 1 (force on) if any decompression

		                     request is detected in atomic contexts;

		- 1 (force on): apply to synchronous reads and small

		                asynchronous reads;

		- 2 (force off): disable synchronous decompression completely.



What:		/sys/fs/erofs/<disk>/drop_caches

Date:		November 2024

fs/erofs/internal.h

+1 −4
Original line number Diff line number Diff line
@@ -59,10 +59,6 @@ enum { 
struct erofs_mount_opts {

	/* current strategy of how to use managed cache */

	unsigned char cache_strategy;

	/* 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;

	unsigned int mount_opt;

};
@@ -116,6 +112,7 @@ struct erofs_sb_info { 
	/* managed XArray arranged in physical block number */

	struct xarray managed_pslots;



	unsigned int sync_decompress;	/* strategy for sync decompression */

	unsigned int shrinker_run_no;

	u16 available_compr_algs;

fs/erofs/super.c

+1 −2
Original line number Diff line number Diff line
@@ -375,8 +375,7 @@ static void erofs_default_options(struct erofs_sb_info *sbi) 
{

#ifdef CONFIG_EROFS_FS_ZIP

	sbi->opt.cache_strategy = EROFS_ZIP_CACHE_READAROUND;

	sbi->opt.max_sync_decompress_pages = 3;

	sbi->opt.sync_decompress = EROFS_SYNC_DECOMPRESS_AUTO;

	sbi->sync_decompress = EROFS_SYNC_DECOMPRESS_AUTO;

#endif

#ifdef CONFIG_EROFS_FS_XATTR

	set_opt(&sbi->opt, XATTR_USER);

fs/erofs/sysfs.c

+1 −1
Original line number Diff line number Diff line
@@ -59,7 +59,7 @@ 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);

EROFS_ATTR_RW_UI(sync_decompress, erofs_sb_info);

EROFS_ATTR_FUNC(drop_caches, 0200);

#endif

#ifdef CONFIG_EROFS_FS_ZIP_ACCEL

fs/erofs/zdata.c

+13 −22
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 
#include <linux/cpuhotplug.h>

#include <trace/events/erofs.h>



#define Z_EROFS_MAX_SYNC_DECOMPRESS_BYTES	12288

#define Z_EROFS_PCLUSTER_MAX_PAGES	(Z_EROFS_PCLUSTER_MAX_SIZE / PAGE_SIZE)

#define Z_EROFS_INLINE_BVECS		2
@@ -1095,21 +1096,6 @@ static int z_erofs_scan_folio(struct z_erofs_frontend *f, 
	return err;

}



static bool z_erofs_is_sync_decompress(struct erofs_sb_info *sbi,

				       unsigned int readahead_pages)

{

	/* auto: enable for read_folio, 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 bool z_erofs_page_is_invalidated(struct page *page)

{

	return !page_folio(page)->mapping && !z_erofs_is_shortlived_page(page);
@@ -1484,9 +1470,9 @@ static void z_erofs_decompress_kickoff(struct z_erofs_decompressqueue *io, 
#else

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

#endif

		/* enable sync decompression for readahead */

		if (sbi->opt.sync_decompress == EROFS_SYNC_DECOMPRESS_AUTO)

			sbi->opt.sync_decompress = EROFS_SYNC_DECOMPRESS_FORCE_ON;

		/* See `sync_decompress` in sysfs-fs-erofs for more details */

		if (sbi->sync_decompress == EROFS_SYNC_DECOMPRESS_AUTO)

			sbi->sync_decompress = EROFS_SYNC_DECOMPRESS_FORCE_ON;

		return;

	}

	z_erofs_decompressqueue_work(&io->u.work);
@@ -1803,16 +1789,21 @@ static void z_erofs_submit_queue(struct z_erofs_frontend *f, 
	z_erofs_decompress_kickoff(q[JQ_SUBMIT], nr_bios);

}



static int z_erofs_runqueue(struct z_erofs_frontend *f, unsigned int rapages)

static int z_erofs_runqueue(struct z_erofs_frontend *f, unsigned int rabytes)

{

	struct z_erofs_decompressqueue io[NR_JOBQUEUES];

	struct erofs_sb_info *sbi = EROFS_I_SB(f->inode);

	bool force_fg = z_erofs_is_sync_decompress(sbi, rapages);

	int syncmode = sbi->sync_decompress;

	bool force_fg;

	int err;



	force_fg = (syncmode == EROFS_SYNC_DECOMPRESS_AUTO && !rabytes) ||

		(syncmode == EROFS_SYNC_DECOMPRESS_FORCE_ON &&

			(rabytes <= Z_EROFS_MAX_SYNC_DECOMPRESS_BYTES));



	if (f->head == Z_EROFS_PCLUSTER_TAIL)

		return 0;

	z_erofs_submit_queue(f, io, &force_fg, !!rapages);

	z_erofs_submit_queue(f, io, &force_fg, !!rabytes);



	/* handle bypass queue (no i/o pclusters) immediately */

	err = z_erofs_decompress_queue(&io[JQ_BYPASS], &f->pagepool);
@@ -1933,7 +1924,7 @@ static void z_erofs_readahead(struct readahead_control *rac) 
	z_erofs_pcluster_readmore(&f, rac, false);

	z_erofs_pcluster_end(&f);



	(void)z_erofs_runqueue(&f, nrpages);

	(void)z_erofs_runqueue(&f, nrpages << PAGE_SHIFT);

	erofs_put_metabuf(&f.map.buf);

	erofs_release_pages(&f.pagepool);

}