Commit 1282dea3 authored by Gao Xiang's avatar Gao Xiang
Browse files

erofs: clean up cached I/O strategies 



After commit 4c7e4255 ("erofs: remove useless cache strategy of
DELAYEDALLOC"), only one cached I/O allocation strategy is supported:

  When cached I/O is preferred, page allocation is applied without
  direct reclaim.  If allocation fails, fall back to inplace I/O.

Let's get rid of z_erofs_cache_alloctype.  No logical changes.

Reviewed-by: default avatarYue Hu <huyue2@coolpad.com>
Reviewed-by: default avatarChao Yu <chao@kernel.org>
Signed-off-by: default avatarYue Hu <huyue2@coolpad.com>
Signed-off-by: default avatarGao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20221206060352.152830-1-xiang@kernel.org
parent 2109901d

fs/erofs/zdata.c

+31 −46
Original line number Diff line number Diff line
@@ -175,16 +175,6 @@ static void z_erofs_free_pcluster(struct z_erofs_pcluster *pcl) 
	DBG_BUGON(1);

}



/* how to allocate cached pages for a pcluster */

enum z_erofs_cache_alloctype {

	DONTALLOC,	/* don't allocate any cached pages */

	/*

	 * try to use cached I/O if page allocation succeeds or fallback

	 * to in-place I/O instead to avoid any direct reclaim.

	 */

	TRYALLOC,

};



/*

 * tagged pointer with 1-bit tag for all compressed pages

 * tag 0 - the page is just found with an extra page reference
@@ -292,12 +282,29 @@ struct z_erofs_decompress_frontend { 
	.inode = __i, .owned_head = Z_EROFS_PCLUSTER_TAIL, \

	.mode = Z_EROFS_PCLUSTER_FOLLOWED, .backmost = true }



static bool z_erofs_should_alloc_cache(struct z_erofs_decompress_frontend *fe)

{

	unsigned int cachestrategy = EROFS_I_SB(fe->inode)->opt.cache_strategy;



	if (cachestrategy <= EROFS_ZIP_CACHE_DISABLED)

		return false;



	if (fe->backmost)

		return true;



	if (cachestrategy >= EROFS_ZIP_CACHE_READAROUND &&

	    fe->map.m_la < fe->headoffset)

		return true;



	return false;

}



static void z_erofs_bind_cache(struct z_erofs_decompress_frontend *fe,

			       enum z_erofs_cache_alloctype type,

			       struct page **pagepool)

{

	struct address_space *mc = MNGD_MAPPING(EROFS_I_SB(fe->inode));

	struct z_erofs_pcluster *pcl = fe->pcl;

	bool shouldalloc = z_erofs_should_alloc_cache(fe);

	bool standalone = true;

	/*

	 * optimistic allocation without direct reclaim since inplace I/O
@@ -326,18 +333,19 @@ static void z_erofs_bind_cache(struct z_erofs_decompress_frontend *fe, 
		} else {

			/* I/O is needed, no possible to decompress directly */

			standalone = false;

			switch (type) {

			case TRYALLOC:

			if (!shouldalloc)

				continue;



			/*

			 * try to use cached I/O if page allocation

			 * succeeds or fallback to in-place I/O instead

			 * to avoid any direct reclaim.

			 */

			newpage = erofs_allocpage(pagepool, gfp);

			if (!newpage)

				continue;

				set_page_private(newpage,

						 Z_EROFS_PREALLOCATED_PAGE);

			set_page_private(newpage, Z_EROFS_PREALLOCATED_PAGE);

			t = tag_compressed_page_justfound(newpage);

				break;

			default:        /* DONTALLOC */

				continue;

			}

		}



		if (!cmpxchg_relaxed(&pcl->compressed_bvecs[i].page, NULL,
@@ -637,20 +645,6 @@ static bool z_erofs_collector_end(struct z_erofs_decompress_frontend *fe) 
	return true;

}



static bool should_alloc_managed_pages(struct z_erofs_decompress_frontend *fe,

				       unsigned int cachestrategy,

				       erofs_off_t la)

{

	if (cachestrategy <= EROFS_ZIP_CACHE_DISABLED)

		return false;



	if (fe->backmost)

		return true;



	return cachestrategy >= EROFS_ZIP_CACHE_READAROUND &&

		la < fe->headoffset;

}



static int z_erofs_read_fragment(struct inode *inode, erofs_off_t pos,

				 struct page *page, unsigned int pageofs,

				 unsigned int len)
@@ -687,12 +681,9 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe, 
				struct page *page, struct page **pagepool)

{

	struct inode *const inode = fe->inode;

	struct erofs_sb_info *const sbi = EROFS_I_SB(inode);

	struct erofs_map_blocks *const map = &fe->map;

	const loff_t offset = page_offset(page);

	bool tight = true, exclusive;



	enum z_erofs_cache_alloctype cache_strategy;

	unsigned int cur, end, spiltted;

	int err = 0;
@@ -746,13 +737,7 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe, 
		fe->mode = Z_EROFS_PCLUSTER_FOLLOWED_NOINPLACE;

	} else {

		/* bind cache first when cached decompression is preferred */

		if (should_alloc_managed_pages(fe, sbi->opt.cache_strategy,

					       map->m_la))

			cache_strategy = TRYALLOC;

		else

			cache_strategy = DONTALLOC;



		z_erofs_bind_cache(fe, cache_strategy, pagepool);

		z_erofs_bind_cache(fe, pagepool);

	}

hitted:

	/*