Linux-Fsdevel Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Ritesh Harjani <riteshh@linux.ibm.com>
To: linux-block@vger.kernel.org
Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org, axboe@kernel.dk,
	Ritesh Harjani <riteshh@linux.ibm.com>,
	Christoph Hellwig <hch@infradead.org>,
	Shivaprasad G Bhat <sbhat@linux.ibm.com>,
	Anju T Sudhakar <anju@linux.vnet.ibm.com>
Subject: [PATCH 1/1] block: Set same_page to false in __bio_try_merge_page if ret is false
Date: Fri, 21 Aug 2020 23:41:17 +0530	[thread overview]
Message-ID: <e50582833c897c1a51a676d7726d1380a3e5a678.1598032711.git.riteshh@linux.ibm.com> (raw)

If we hit the UINT_MAX limit of bio->bi_iter.bi_size and so we are anyway
not merging this page in this bio, then it make sense to make same_page
also as false before returning.

Without this patch, we hit below WARNING in iomap.
This mostly happens with very large memory system and / or after tweaking
vm dirty threshold params to delay writeback of dirty data.

WARNING: CPU: 18 PID: 5130 at fs/iomap/buffered-io.c:74 iomap_page_release+0x120/0x150
 CPU: 18 PID: 5130 Comm: fio Kdump: loaded Tainted: G        W         5.8.0-rc3 #6
 Call Trace:
  __remove_mapping+0x154/0x320 (unreliable)
  iomap_releasepage+0x80/0x180
  try_to_release_page+0x94/0xe0
  invalidate_inode_page+0xc8/0x110
  invalidate_mapping_pages+0x1dc/0x540
  generic_fadvise+0x3c8/0x450
  xfs_file_fadvise+0x2c/0xe0 [xfs]
  vfs_fadvise+0x3c/0x60
  ksys_fadvise64_64+0x68/0xe0
  sys_fadvise64+0x28/0x40
  system_call_exception+0xf8/0x1c0
  system_call_common+0xf0/0x278

Suggested-by: Christoph Hellwig <hch@infradead.org>
Reported-by: Shivaprasad G Bhat <sbhat@linux.ibm.com>
Signed-off-by: Anju T Sudhakar <anju@linux.vnet.ibm.com>
Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
---
[prev discussion]:- https://patchwork.kernel.org/patch/11723453/

 block/bio.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/block/bio.c b/block/bio.c
index a7366c02c9b5..675ecd81047b 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -877,8 +877,10 @@ bool __bio_try_merge_page(struct bio *bio, struct page *page,
 		struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1];
 
 		if (page_is_mergeable(bv, page, len, off, same_page)) {
-			if (bio->bi_iter.bi_size > UINT_MAX - len)
+			if (bio->bi_iter.bi_size > UINT_MAX - len) {
+				*same_page = false;
 				return false;
+			}
 			bv->bv_len += len;
 			bio->bi_iter.bi_size += len;
 			return true;
-- 
2.25.4


             reply	other threads:[~2020-08-21 18:11 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-21 18:11 Ritesh Harjani [this message]
2020-08-27  6:14 ` Ritesh Harjani

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=e50582833c897c1a51a676d7726d1380a3e5a678.1598032711.git.riteshh@linux.ibm.com \
    --to=riteshh@linux.ibm.com \
    --cc=anju@linux.vnet.ibm.com \
    --cc=axboe@kernel.dk \
    --cc=hch@infradead.org \
    --cc=linux-block@vger.kernel.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-xfs@vger.kernel.org \
    --cc=sbhat@linux.ibm.com \
    --subject='Re: [PATCH 1/1] block: Set same_page to false in __bio_try_merge_page if ret is false' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).