From: Dave Chinner <david@fromorbit.com> To: Eric Biggers <ebiggers@kernel.org> Cc: Jaegeuk Kim <jaegeuk@kernel.org>, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-block@vger.kernel.org, linux-xfs@vger.kernel.org Subject: Re: [PATCH] f2fs: add sysfs entry to avoid FUA Date: Sat, 28 May 2022 09:55:09 +1000 [thread overview] Message-ID: <20220527235509.GW1098723@dread.disaster.area> (raw) In-Reply-To: <YpFDw3mQjN1LBd2j@gmail.com> On Fri, May 27, 2022 at 09:33:55PM +0000, Eric Biggers wrote: > [+Cc linux-block for FUA, and linux-xfs for iomap] linux-fsdevel should really be used for iomap stuff... > > On Fri, May 27, 2022 at 01:59:55PM -0700, Jaegeuk Kim wrote: > > Some UFS storage gives slower performance on FUA than write+cache_flush. > > Let's give a way to manage it. > > > > Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> > > Should the driver even be saying that it has FUA support in this case? If the > driver didn't claim FUA support, that would also solve this problem. Agreed, this is a hardware problem that need to addressed with a driver quirk to stop it advertising FUA support. The high level fs/iomap code should always issue FUA writes where possible and the lower layers tell the block layer whether to issue the FUA as a FUA or write+cache flush pair. And, quite frankly, exposing this sort of "hardware needs help" knob as a sysfs variable is exactly the sort of thing we should never do. Users have no idea how to tune stuff like this correctly (even if they knew it existed!), yet we know exactly what hardware has this problem and the kernel already has mechanisms that would allow it to just Do The Right Thing. IOWs, we can fix this without the user even having to know that they have garbage hardware that needs special help.... Cheers, Dave. -- Dave Chinner david@fromorbit.com
WARNING: multiple messages have this Message-ID (diff)
From: Dave Chinner <david@fromorbit.com> To: Eric Biggers <ebiggers@kernel.org> Cc: linux-block@vger.kernel.org, Jaegeuk Kim <jaegeuk@kernel.org>, linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Subject: Re: [f2fs-dev] [PATCH] f2fs: add sysfs entry to avoid FUA Date: Sat, 28 May 2022 09:55:09 +1000 [thread overview] Message-ID: <20220527235509.GW1098723@dread.disaster.area> (raw) In-Reply-To: <YpFDw3mQjN1LBd2j@gmail.com> On Fri, May 27, 2022 at 09:33:55PM +0000, Eric Biggers wrote: > [+Cc linux-block for FUA, and linux-xfs for iomap] linux-fsdevel should really be used for iomap stuff... > > On Fri, May 27, 2022 at 01:59:55PM -0700, Jaegeuk Kim wrote: > > Some UFS storage gives slower performance on FUA than write+cache_flush. > > Let's give a way to manage it. > > > > Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> > > Should the driver even be saying that it has FUA support in this case? If the > driver didn't claim FUA support, that would also solve this problem. Agreed, this is a hardware problem that need to addressed with a driver quirk to stop it advertising FUA support. The high level fs/iomap code should always issue FUA writes where possible and the lower layers tell the block layer whether to issue the FUA as a FUA or write+cache flush pair. And, quite frankly, exposing this sort of "hardware needs help" knob as a sysfs variable is exactly the sort of thing we should never do. Users have no idea how to tune stuff like this correctly (even if they knew it existed!), yet we know exactly what hardware has this problem and the kernel already has mechanisms that would allow it to just Do The Right Thing. IOWs, we can fix this without the user even having to know that they have garbage hardware that needs special help.... Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
next prev parent reply other threads:[~2022-05-27 23:55 UTC|newest] Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-05-27 20:59 [PATCH] f2fs: add sysfs entry to avoid FUA Jaegeuk Kim 2022-05-27 20:59 ` [f2fs-dev] " Jaegeuk Kim 2022-05-27 21:33 ` Eric Biggers 2022-05-27 21:33 ` [f2fs-dev] " Eric Biggers 2022-05-27 23:55 ` Dave Chinner [this message] 2022-05-27 23:55 ` Dave Chinner 2022-05-28 0:26 ` Jaegeuk Kim 2022-05-28 0:26 ` [f2fs-dev] " Jaegeuk Kim 2022-05-28 5:12 ` Dave Chinner 2022-05-28 5:12 ` [f2fs-dev] " Dave Chinner 2022-05-28 1:06 ` Jaegeuk Kim 2022-05-28 1:06 ` [f2fs-dev] " Jaegeuk Kim 2022-05-28 1:42 ` Darrick J. Wong 2022-05-28 1:42 ` [f2fs-dev] " Darrick J. Wong 2022-05-28 5:03 ` Christoph Hellwig 2022-05-28 5:03 ` [f2fs-dev] " Christoph Hellwig 2022-05-31 20:15 ` Jaegeuk Kim 2022-05-31 20:15 ` [f2fs-dev] " Jaegeuk Kim 2022-05-28 1:07 ` [RFC PATCH v2] " Jaegeuk Kim 2022-05-28 1:07 ` [f2fs-dev] " Jaegeuk Kim
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