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From: hch <hch@lst.de>
To: Hans Holmberg <Hans.Holmberg@wdc.com>
Cc: "linux-xfs@vger.kernel.org" <linux-xfs@vger.kernel.org>,
	Carlos Maiolino <cem@kernel.org>,
	Dave Chinner <david@fromorbit.com>,
	"Darrick J . Wong" <djwong@kernel.org>, hch <hch@lst.de>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH 0/2] Add mru cache for inode to zone allocation mapping
Date: Mon, 5 May 2025 07:57:56 +0200	[thread overview]
Message-ID: <20250505055756.GB21256@lst.de> (raw)
In-Reply-To: <20250430084117.9850-1-hans.holmberg@wdc.com>

On Wed, Apr 30, 2025 at 08:41:20AM +0000, Hans Holmberg wrote:
> Sending out as an RFC to get comments, specifically about the potential
> mru lock contention when doing the lookup during allocation.

I am a little worried about that.  The MRU cache is implemented right
now rotates the mru list on every lookup under a mru-cache wide lock,
which is bit of a performance nightmare.

I wonder if we can do some form of batched move between the mru buckets
that can reduce the locking and cacheline write impact.

But maybe it's worth to give this a try and work from performance reports
as needed.


      parent reply	other threads:[~2025-05-05  5:58 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-04-30  8:41 [RFC PATCH 0/2] Add mru cache for inode to zone allocation mapping Hans Holmberg
2025-04-30  8:41 ` [RFC PATCH 2/2] xfs: add inode to zone caching for data placement Hans Holmberg
2025-05-02 20:04   ` Darrick J. Wong
2025-05-05  5:55     ` hch
2025-04-30  8:41 ` [RFC PATCH 1/2] xfs: free the item in xfs_mru_cache_insert on failure Hans Holmberg
2025-05-02 20:06   ` Darrick J. Wong
2025-05-05  5:45     ` hch
2025-05-05 15:07       ` Darrick J. Wong
2025-05-05  5:57 ` hch [this message]

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