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From: Cyril Hrubis <chrubis@suse.cz>
To: Wei Gao <wegao@suse.com>
Cc: ltp@lists.linux.it
Subject: Re: [LTP] [PATCH v1] swapon04: Settle udev after mkswap to prevent tmpfs hole filling
Date: Thu, 12 Nov 2026 11:49:56 +0100	[thread overview]
Message-ID: <avWZ1FX6GvTI5DOT@yuki.lan> (raw)
In-Reply-To: <20261111081150.15101-1-wegao@suse.com>

Hi!
> When mkswap formats and closes the loop device, systemd-udevd
> asynchronously runs blkid probing on the device. On kernels prior to
> 5.18, tmpfs shmem_file_read_iter() treats non-iovec read iterators
> (!iter_is_iovec(to)) as stacking filesystem reads, allocating real
> zero-filled pages into holes (this behavior get fixed by commit
> 56a8c8eb1eaf ("tmpfs: do not allocate pages on read")).

Also when this has been fixed by 5.18 we shouldn't apply the fix for
5.18+ otherwise this would mask regressions.

-- 
Cyril Hrubis
chrubis@suse.cz

-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

  parent reply	other threads:[~2026-11-12 10:49 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-11-11  8:09 [LTP] [PATCH v1] swapon04: Settle udev after mkswap to prevent tmpfs hole filling Wei Gao via ltp
2026-11-11  8:30 ` [LTP] " linuxtestproject.agent
2026-11-12 10:44 ` [LTP] [PATCH v1] " Cyril Hrubis
2026-11-12 10:49 ` Cyril Hrubis [this message]
2026-11-13  3:08 ` [LTP] [PATCH v2] swapon04: Settle udev after mkswap on kernels < 5.18 Wei Gao via ltp

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