Re: [PATCH net-next] avoid fragmenting page memory with netdev_alloc_cache
From: Ronak Doshi
Date: Wed Feb 24 2021 - 14:33:26 EST
On 2/11/21, 4:18 PM, "Ronak Doshi" <doshir@xxxxxxxxxx> wrote:
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From: Todd Sabin <tsabin@xxxxxxxxxx>
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Linux network stack uses an allocation page cache for skbs. The
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purpose is to reduce the number of page allocations that it needs to
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make, and it works by allocating a group of pages, and then
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sub-allocating skb memory from them. When all skbs referencing the
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shared pages are freed, then the block of pages is finally freed.
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When these skbs are all freed close together in time, this works fine.
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However, what can happen is that there are multiple nics (or multiple
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rx-queues in a single nic), and the skbs are allocated to fill the rx
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ring(s). If some nics or queues are far more active than others, the
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entries in the less busy nic/queue may end up referencing a page
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block, while all of the other packets that referenced that block of
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pages are freed.
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The result of this is that the memory used by an appliance for its rx
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rings can slowly grow to be much greater than it was originally.
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This patch fixes that by giving each vmxnet3 device a per-rx-queue page
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cache.
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Signed-off-by: Todd Sabin <tsabin@xxxxxxxxxx>
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Signed-off-by: Ronak Doshi <doshir@xxxxxxxxxx>
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---
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drivers/net/vmxnet3/vmxnet3_drv.c | 30 ++++++++++++++++++++++++------
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drivers/net/vmxnet3/vmxnet3_int.h | 2 ++
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include/linux/skbuff.h | 2 ++
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net/core/skbuff.c | 21 +++++++++++++++------
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4 files changed, 43 insertions(+), 12 deletions(-)
Any update on this patch?
Thanks,
Ronak