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From:   =?UTF-8?q?Thomas=20Wei=C3=9Fschuh?= <linux@weissschuh.net>
To:     Keith Busch <kbusch@kernel.org>, Jens Axboe <axboe@fb.com>,
        Christoph Hellwig <hch@lst.de>,
        Sagi Grimberg <sagi@grimberg.me>, linux-kernel@vger.kernel.org
Cc:     linux-nvme@lists.infradead.org,
        =?UTF-8?q?Thomas=20Wei=C3=9Fschuh?= <linux@weissschuh.net>
Subject: [PATCH] nvme-pci: fix host memory buffer allocation size
Date:   Thu, 28 Apr 2022 12:19:22 +0200
Message-Id: <20220428101922.14216-1-linux@weissschuh.net>
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We want to allocate the smallest possible amount of buffers with the
largest possible size (1 buffer of size "hmpre").

Previously we were allocating as many buffers as possible of the smallest
possible size.
This also lead to "hmpre" to not be satisifed as not enough buffer slots
where available.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---

Also discussed at https://lore.kernel.org/linux-nvme/f94565db-f217-4a56-83c3-c6429807185c@t-8ch.de/

 drivers/nvme/host/pci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 3aacf1c0d5a5..0546523cc20b 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -2090,7 +2090,7 @@ static int __nvme_alloc_host_mem(struct nvme_dev *dev, u64 preferred,
 
 static int nvme_alloc_host_mem(struct nvme_dev *dev, u64 min, u64 preferred)
 {
-	u64 min_chunk = min_t(u64, preferred, PAGE_SIZE * MAX_ORDER_NR_PAGES);
+	u64 min_chunk = max_t(u64, preferred, PAGE_SIZE * MAX_ORDER_NR_PAGES);
 	u64 hmminds = max_t(u32, dev->ctrl.hmminds * 4096, PAGE_SIZE * 2);
 	u64 chunk_size;
 

base-commit: 46cf2c613f4b10eb12f749207b0fd2c1bfae3088
-- 
2.36.0