This patch assigns the max folio order for readahead. After applying this patch, it starts with high-order page allocation successfully as shown in the below traces.
Before: f2fs_fadvise: dev = (252,16), ino = 14, i_size = 4294967296 offset:0, len:536870912, advise:3 page_cache_sync_ra: dev=252:16 ino=e index=0 req_count=2048 order=0 size=0 async_size=0 ra_pages=2048 mmap_miss=0 prev_pos=-1 page_cache_ra_order: dev=252:16 ino=e index=0 order=0 size=2048 async_size=1024 ra_pages=2048 page_cache_sync_ra: dev=252:16 ino=e index=2048 req_count=2048 order=0 size=2048 async_size=1024 ra_pages=2048 mmap_miss=0 prev_pos=-1 page_cache_ra_unbounded: dev=252:16 ino=e index=2048 nr_to_read=2048 lookahead_size=0 page_cache_sync_ra: dev=252:16 ino=e index=4096 req_count=2048 order=0 size=2048 async_size=1024 ra_pages=2048 mmap_miss=0 prev_pos=-1 page_cache_ra_unbounded: dev=252:16 ino=e index=4096 nr_to_read=2048 lookahead_size=0 page_cache_sync_ra: dev=252:16 ino=e index=6144 req_count=2048 order=0 size=2048 async_size=1024 ra_pages=2048 mmap_miss=0 prev_pos=-1 page_cache_ra_unbounded: dev=252:16 ino=e index=6144 nr_to_read=2048 lookahead_size=0 ... page_cache_sync_ra: dev=252:16 ino=e index=129024 req_count=2048 order=0 size=2048 async_size=1024 ra_pages=2048 mmap_miss=0 prev_pos=-1 page_cache_ra_unbounded: dev=252:16 ino=e index=129024 nr_to_read=2048 lookahead_size=0 After: f2fs_fadvise: dev = (252,16), ino = 14, i_size = 4294967296 offset:0, len:536870912, advise:3 page_cache_sync_ra: dev=252:16 ino=e index=0 req_count=2048 order=0 size=0 async_size=0 ra_pages=2048 mmap_miss=0 prev_pos=-1 page_cache_ra_order: dev=252:16 ino=e index=0 order=2 size=2048 async_size=1024 ra_pages=2048 page_cache_sync_ra: dev=252:16 ino=e index=2048 req_count=2048 order=2 size=2048 async_size=1024 ra_pages=2048 mmap_miss=0 prev_pos=-1 page_cache_ra_order: dev=252:16 ino=e index=2048 order=4 size=2048 async_size=1024 ra_pages=2048 page_cache_sync_ra: dev=252:16 ino=e index=4096 req_count=2048 order=4 size=2048 async_size=1024 ra_pages=2048 mmap_miss=0 prev_pos=-1 page_cache_ra_order: dev=252:16 ino=e index=4096 order=6 size=2048 async_size=1024 ra_pages=2048 page_cache_sync_ra: dev=252:16 ino=e index=6144 req_count=2048 order=6 size=2048 async_size=1024 ra_pages=2048 mmap_miss=0 prev_pos=-1 page_cache_ra_order: dev=252:16 ino=e index=6144 order=8 size=2048 async_size=1024 ra_pages=2048 page_cache_sync_ra: dev=252:16 ino=e index=8192 req_count=2048 order=8 size=2048 async_size=1024 ra_pages=2048 mmap_miss=0 prev_pos=-1 page_cache_ra_order: dev=252:16 ino=e index=8192 order=10 size=2048 async_size=1024 ra_pages=2048 page_cache_sync_ra: dev=252:16 ino=e index=10240 req_count=2048 order=9 size=2048 async_size=1024 ra_pages=2048 mmap_miss=0 prev_pos=-1 page_cache_ra_order: dev=252:16 ino=e index=10240 order=11 size=2048 async_size=1024 ra_pages=2048 ... page_cache_ra_order: dev=252:16 ino=e index=126976 order=11 size=2048 async_size=1024 ra_pages=2048 page_cache_sync_ra: dev=252:16 ino=e index=129024 req_count=2048 order=9 size=2048 async_size=1024 ra_pages=2048 mmap_miss=0 prev_pos=-1 page_cache_ra_order: dev=252:16 ino=e index=129024 order=11 size=2048 async_size=1024 ra_pages=2048 page_cache_async_ra: dev=252:16 ino=e index=1024 req_count=2048 order=9 size=2048 async_size=1024 ra_pages=2048 mmap_miss=0 prev_pos=-1 For comparion, this is the trace of madvise(MADV_POPULATE_READ) which bumps up the order by 2. page_cache_ra_order: dev=252:16 ino=e index=0 order=0 size=2048 async_size=512 ra_pages=2048 f2fs_filemap_fault: dev = (252,16), ino = 14, index = 0, flags: WRITE|KILLABLE|USER|REMOTE|0x8082000, ret: MAJOR|RETRY page_cache_async_ra: dev=252:16 ino=e index=1536 req_count=2048 order=0 size=2048 async_size=512 ra_pages=2048 mmap_miss=0 prev_pos=-1 page_cache_ra_order: dev=252:16 ino=e index=2048 order=2 size=2048 async_size=2048 ra_pages=2048 f2fs_filemap_fault: dev = (252,16), ino = 14, index = 1536, flags: WRITE|KILLABLE|USER|REMOTE|0x8082000, ret: RETRY page_cache_async_ra: dev=252:16 ino=e index=2048 req_count=2048 order=2 size=2048 async_size=2048 ra_pages=2048 mmap_miss=0 prev_pos=-1 page_cache_ra_order: dev=252:16 ino=e index=4096 order=4 size=2048 async_size=2048 ra_pages=2048 f2fs_filemap_fault: dev = (252,16), ino = 14, index = 2048, flags: WRITE|KILLABLE|USER|REMOTE|0x8082000, ret: RETRY page_cache_async_ra: dev=252:16 ino=e index=4096 req_count=2048 order=4 size=2048 async_size=2048 ra_pages=2048 mmap_miss=0 prev_pos=-1 page_cache_ra_order: dev=252:16 ino=e index=6144 order=6 size=2048 async_size=2048 ra_pages=2048 f2fs_filemap_fault: dev = (252,16), ino = 14, index = 4096, flags: WRITE|KILLABLE|USER|REMOTE|0x8082000, ret: RETRY page_cache_async_ra: dev=252:16 ino=e index=6144 req_count=2048 order=6 size=2048 async_size=2048 ra_pages=2048 mmap_miss=0 prev_pos=-1 page_cache_ra_order: dev=252:16 ino=e index=8192 order=8 size=2048 async_size=2048 ra_pages=2048 f2fs_filemap_fault: dev = (252,16), ino = 14, index = 6144, flags: WRITE|KILLABLE|USER|REMOTE|0x8082000, ret: RETRY page_cache_async_ra: dev=252:16 ino=e index=8192 req_count=2048 order=8 size=2048 async_size=2048 ra_pages=2048 mmap_miss=0 prev_pos=-1 page_cache_ra_order: dev=252:16 ino=e index=10240 order=10 size=2048 async_size=2048 ra_pages=2048 f2fs_filemap_fault: dev = (252,16), ino = 14, index = 8192, flags: WRITE|KILLABLE|USER|REMOTE|0x8082000, ret: RETRY page_cache_async_ra: dev=252:16 ino=e index=10240 req_count=2048 order=9 size=2048 async_size=2048 ra_pages=2048 mmap_miss=0 prev_pos=-1 ... f2fs_filemap_fault: dev = (252,16), ino = 14, index = 518144, flags: WRITE|KILLABLE|USER|REMOTE|0x8082000, ret: RETRY page_cache_async_ra: dev=252:16 ino=e index=520192 req_count=2048 order=9 size=2048 async_size=2048 ra_pages=2048 mmap_miss=0 prev_pos=-1 page_cache_ra_order: dev=252:16 ino=e index=522240 order=11 size=2048 async_size=2048 ra_pages=2048 f2fs_filemap_fault: dev = (252,16), ino = 14, index = 520192, flags: WRITE|KILLABLE|USER|REMOTE|0x8082000, ret: RETRY page_cache_async_ra: dev=252:16 ino=e index=522240 req_count=2048 order=9 size=2048 async_size=2048 ra_pages=2048 mmap_miss=0 prev_pos=-1 page_cache_ra_order: dev=252:16 ino=e index=524288 order=11 size=2048 async_size=2048 ra_pages=2048 f2fs_filemap_fault: dev = (252,16), ino = 14, index = 522240, flags: WRITE|KILLABLE|USER|REMOTE|0x8082000, ret: RETRY Cc: [email protected] Cc: Matthew Wilcox (Oracle) <[email protected]> Signed-off-by: Jaegeuk Kim <[email protected]> --- Change log from v1: - take the same madvise() behavior which bumps up ra->order by 2. mm/readahead.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/mm/readahead.c b/mm/readahead.c index 54c78f8276fe..61a469117209 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -593,7 +593,8 @@ void page_cache_sync_ra(struct readahead_control *ractl, * trivial case: (index - prev_index) == 1 * unaligned reads: (index - prev_index) == 0 */ - if (!index || req_count > max_pages || index - prev_index <= 1UL) { + if (!index || req_count > max_pages || index - prev_index <= 1UL || + mapping_large_folio_support(ractl->mapping)) { ra->start = index; ra->size = get_init_ra_size(req_count, max_pages); ra->async_size = ra->size > req_count ? ra->size - req_count : @@ -627,7 +628,7 @@ void page_cache_sync_ra(struct readahead_control *ractl, ra->size = min(contig_count + req_count, max_pages); ra->async_size = 1; readit: - ra->order = 0; + ra->order += 2; ractl->_index = ra->start; page_cache_ra_order(ractl, ra); } -- 2.52.0.223.gf5cc29aaa4-goog _______________________________________________ Linux-f2fs-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
