From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DC08C2E11DC for ; Wed, 3 Dec 2025 23:25:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764804327; cv=none; b=MkgBWBcnzC+D5c5rsproIJA3wYHs6KQdpA6iWa43Od6Yp2V5NZPlencVTy4Os6Uv2utWV2psYJp5CmvJMBKsztY0Z9P21ywhs2Lde3lbFSGhwvl2yr68xLgnZyTcgigqLSBDe7cx7zz3rwOQ590wfIAtdzujrWV5/p15vB3b3xU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764804327; c=relaxed/simple; bh=sAJej4HZTiYDfV7VEYcwaKg9Xwk914WW6wlk1yPGQEk=; h=Date:From:To:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=upTvaGq3+jyyejuD03fo1/GzJy/YKXr9e8iNzus4aaZfML6HT+7sfQVGXQ78p9bYTCb6uYYS/kRJrxy+hyePWm4bfkuQOMCNILGKC3tzkTQ6PkCC+iQHjotT6Dsdhkc62OOC79kxd+LHOaOmL7K7hAz2130TRhtUD8g57wQHEaw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=pQzPjEFP; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="pQzPjEFP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 430AEC19424; Wed, 3 Dec 2025 23:25:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1764804327; bh=sAJej4HZTiYDfV7VEYcwaKg9Xwk914WW6wlk1yPGQEk=; h=Date:From:To:Subject:References:In-Reply-To:From; b=pQzPjEFPD8N74U1fP1gOFDJDMKcIZviYG5+wt0HlBqPGc0RIFUQQW6xd4cnrlyWMq P+Mddndf3V5rcRbC1NkvnFKPsD5HVrspRuDuRkMuJ9YYxbmFpBdRpD5cOfet1H0e+F vD4Ikj+8E/yma5BlgCY/ipAKL46xBGTnuFDdnTI0H1jem5Y1DOlRFu4MWybtgZbb8G +mxx1ZViFrEiDfRwRcCTUIjWRvSOEfqBF9wlB+fLW9LQyTJBphmKyGONFOc72r6nQq kaOwqWlPK8LxWDOTkff6xuvGUAO0mEnPQAibAZRi8BipuaVQ5TAHTH1A9qX7jqJVJ9 424U5byWd05LQ== Date: Wed, 3 Dec 2025 23:25:25 +0000 From: Jaegeuk Kim To: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-mm@kvack.org, Matthew Wilcox Subject: Re: [PATCH 3/3 v2] mm/readahead: try to allocate high order pages for FADVISE_FAV_WILLNEED Message-ID: References: <20251202013212.964298-1-jaegeuk@kernel.org> <20251202013212.964298-4-jaegeuk@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251202013212.964298-4-jaegeuk@kernel.org> 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: linux-mm@kvack.org Cc: Matthew Wilcox (Oracle) Signed-off-by: Jaegeuk Kim --- 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