From: Gao Xiang <[email protected]> Previously, the requested read length is strictly followed by EROFS decompression strategy. However, it's quite inefficient to apply partial decompression if non-negligible data in big pclusters needs to be handled, especially for the upcoming LZMA algorithm.
Let's decompress more for the cases above as what other fses did. Signed-off-by: Gao Xiang <[email protected]> --- fs/erofs/internal.h | 16 ++++++++ fs/erofs/zdata.c | 94 ++++++++++++++++++++++++++++++++++++--------- fs/erofs/zmap.c | 4 +- 3 files changed, 94 insertions(+), 20 deletions(-) diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h index 48bfc6eb2b02..e7378795a26c 100644 --- a/fs/erofs/internal.h +++ b/fs/erofs/internal.h @@ -307,6 +307,19 @@ static inline unsigned int erofs_inode_datalayout(unsigned int value) EROFS_I_DATALAYOUT_BITS); } +/* + * Different from grab_cache_page_nowait(), reclaiming is never triggered + * when allocating new pages. + */ +static inline +struct page *erofs_grab_cache_page_nowait(struct address_space *mapping, + pgoff_t index) +{ + return pagecache_get_page(mapping, index, + FGP_LOCK|FGP_CREAT|FGP_NOFS|FGP_NOWAIT, + readahead_gfp_mask(mapping) & ~__GFP_RECLAIM); +} + extern const struct super_operations erofs_sops; extern const struct address_space_operations erofs_raw_access_aops; @@ -368,6 +381,8 @@ struct erofs_map_blocks { * approach instead if possible since it's more metadata lightweight.) */ #define EROFS_GET_BLOCKS_FIEMAP 0x0002 +/* Used to map the whole extent if non-negligible data is already requested */ +#define EROFS_GET_BLOCKS_READMORE 0x0004 enum { Z_EROFS_COMPRESSION_SHIFTED = Z_EROFS_COMPRESSION_MAX, @@ -375,6 +390,7 @@ enum { }; /* zmap.c */ +#define Z_EROFS_LZ4_READMORE_THRESHOLD (9 * EROFS_BLKSIZ) extern const struct iomap_ops z_erofs_iomap_report_ops; #ifdef CONFIG_EROFS_FS_ZIP diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c index 5c34ef66677f..a1861a9acfd0 100644 --- a/fs/erofs/zdata.c +++ b/fs/erofs/zdata.c @@ -1377,6 +1377,67 @@ static void z_erofs_runqueue(struct super_block *sb, z_erofs_decompress_queue(&io[JQ_SUBMIT], pagepool); } +static void z_erofs_pcluster_readmore(struct z_erofs_decompress_frontend *f, + struct readahead_control *rac, + erofs_off_t end, + struct list_head *pagepool, + bool backmost) +{ + struct inode *const inode = f->inode; + struct erofs_map_blocks *const map = &f->map; + erofs_off_t cur; + int err; + + if (backmost) { + map->m_la = end; + err = z_erofs_map_blocks_iter(inode, map, + EROFS_GET_BLOCKS_READMORE); + if (err) + return; + end = round_up(end, PAGE_SIZE); + + /* expend ra for the trailing edge if readahead */ + if (rac) { + loff_t newstart = readahead_pos(rac); + + readahead_expand(rac, newstart, end - newstart); + return; + } + } else { + end = round_up(map->m_la, PAGE_SIZE); + + if (!map->m_llen) + return; + } + + cur = map->m_la + map->m_llen - 1; + while (cur >= end) { + pgoff_t index = cur >> PAGE_SHIFT; + struct page *page; + + page = erofs_grab_cache_page_nowait(inode->i_mapping, index); + if (!page) + goto skip; + + if (PageUptodate(page)) { + unlock_page(page); + put_page(page); + goto skip; + } + + err = z_erofs_do_read_page(f, page, pagepool); + if (err) + erofs_err(inode->i_sb, + "readmore error at page %lu @ nid %llu", + index, EROFS_I(inode)->nid); + put_page(page); +skip: + if (cur < PAGE_SIZE) + break; + cur = (index << PAGE_SHIFT) - 1; + } +} + static int z_erofs_readpage(struct file *file, struct page *page) { struct inode *const inode = page->mapping->host; @@ -1385,10 +1446,13 @@ static int z_erofs_readpage(struct file *file, struct page *page) LIST_HEAD(pagepool); trace_erofs_readpage(page, false); - f.headoffset = (erofs_off_t)page->index << PAGE_SHIFT; + z_erofs_pcluster_readmore(&f, NULL, f.headoffset + PAGE_SIZE - 1, + &pagepool, true); err = z_erofs_do_read_page(&f, page, &pagepool); + z_erofs_pcluster_readmore(&f, NULL, 0, &pagepool, false); + (void)z_erofs_collector_end(&f.clt); /* if some compressed cluster ready, need submit them anyway */ @@ -1409,29 +1473,20 @@ static void z_erofs_readahead(struct readahead_control *rac) { struct inode *const inode = rac->mapping->host; struct erofs_sb_info *const sbi = EROFS_I_SB(inode); - - unsigned int nr_pages = readahead_count(rac); - bool sync = (sbi->ctx.readahead_sync_decompress && - nr_pages <= sbi->ctx.max_sync_decompress_pages); struct z_erofs_decompress_frontend f = DECOMPRESS_FRONTEND_INIT(inode); struct page *page, *head = NULL; + unsigned int nr_pages; LIST_HEAD(pagepool); - trace_erofs_readpages(inode, readahead_index(rac), nr_pages, false); - f.readahead = true; f.headoffset = readahead_pos(rac); - while ((page = readahead_page(rac))) { - prefetchw(&page->flags); - - /* - * A pure asynchronous readahead is indicated if - * a PG_readahead marked page is hitted at first. - * Let's also do asynchronous decompression for this case. - */ - sync &= !(PageReadahead(page) && !head); + z_erofs_pcluster_readmore(&f, rac, f.headoffset + + readahead_length(rac) - 1, &pagepool, true); + nr_pages = readahead_count(rac); + trace_erofs_readpages(inode, readahead_index(rac), nr_pages, false); + while ((page = readahead_page(rac))) { set_page_private(page, (unsigned long)head); head = page; } @@ -1450,11 +1505,12 @@ static void z_erofs_readahead(struct readahead_control *rac) page->index, EROFS_I(inode)->nid); put_page(page); } - + z_erofs_pcluster_readmore(&f, rac, 0, &pagepool, false); (void)z_erofs_collector_end(&f.clt); - z_erofs_runqueue(inode->i_sb, &f, &pagepool, sync); - + z_erofs_runqueue(inode->i_sb, &f, &pagepool, + sbi->ctx.readahead_sync_decompress && + nr_pages <= sbi->ctx.max_sync_decompress_pages); if (f.map.mpage) put_page(f.map.mpage); diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c index a61cc7f55ef0..7f42a1c8a338 100644 --- a/fs/erofs/zmap.c +++ b/fs/erofs/zmap.c @@ -673,7 +673,9 @@ int z_erofs_map_blocks_iter(struct inode *inode, else map->m_algorithmformat = vi->z_algorithmtype[0]; - if (flags & EROFS_GET_BLOCKS_FIEMAP) { + if (flags & EROFS_GET_BLOCKS_FIEMAP || + ((flags & EROFS_GET_BLOCKS_READMORE) && + map->m_llen >= Z_EROFS_LZ4_READMORE_THRESHOLD)) { err = z_erofs_get_extent_decompressedlen(&m); if (!err) map->m_flags |= EROFS_MAP_FULL_MAPPED; -- 2.20.1
