Searched hist:9451980 (Results 1 – 1 of 1) sorted by relevance
| /openbmc/linux/net/core/ |
| H A D | skbuff.c | a080e7bd Wed May 13 15:34:13 CDT 2015 Alexander Duyck <alexander.h.duyck@redhat.com> net: Reserve skb headroom and set skb->dev even if using __alloc_skb
When I had inlined __alloc_rx_skb into __netdev_alloc_skb and
__napi_alloc_skb I had overlooked the fact that there was a return in the
__alloc_rx_skb. As a result we weren't reserving headroom or setting the
skb->dev in certain cases. This change corrects that by adding a couple of
jump labels to jump to depending on __alloc_skb either succeeding or failing.
Fixes: 9451980a6646 ("net: Use cached copy of pfmemalloc to avoid accessing page")
Reported-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Tested-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
9451980a Wed May 06 23:11:40 CDT 2015 Alexander Duyck <alexander.h.duyck@redhat.com> net: Use cached copy of pfmemalloc to avoid accessing page
While testing I found that the testing for pfmemalloc in build_skb was
rather expensive. I found the issue to be two-fold. First we have to get
from the virtual address to the head page and that comes at the cost of
something like 11 cycles. Then there is the cost for reading pfmemalloc out
of the head page which can be cache cold due to the fact that
put_page_testzero is likely invalidating the cache-line on one or more
CPUs as the fragments can be shared.
To avoid this extra expense I have added a pfmemalloc member to the
netdev_alloc_cache. I then pushed pieces of __alloc_rx_skb into
__napi_alloc_skb and __netdev_alloc_skb so that I could rewrite them to
make use of the cached pfmemalloc value. The result is that my perf traces
show a reduction from 9.28% overhead to 3.7% for the code covered by
build_skb, __alloc_rx_skb, and __napi_alloc_skb when performing a test with
the packet being dropped instead of being handed to napi_gro_receive.
Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
a080e7bd Wed May 13 15:34:13 CDT 2015 Alexander Duyck <alexander.h.duyck@redhat.com> net: Reserve skb headroom and set skb->dev even if using __alloc_skb
When I had inlined __alloc_rx_skb into __netdev_alloc_skb and
__napi_alloc_skb I had overlooked the fact that there was a return in the
__alloc_rx_skb. As a result we weren't reserving headroom or setting the
skb->dev in certain cases. This change corrects that by adding a couple of
jump labels to jump to depending on __alloc_skb either succeeding or failing.
Fixes: 9451980a6646 ("net: Use cached copy of pfmemalloc to avoid accessing page")
Reported-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Tested-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
9451980a Wed May 06 23:11:40 CDT 2015 Alexander Duyck <alexander.h.duyck@redhat.com> net: Use cached copy of pfmemalloc to avoid accessing page
While testing I found that the testing for pfmemalloc in build_skb was
rather expensive. I found the issue to be two-fold. First we have to get
from the virtual address to the head page and that comes at the cost of
something like 11 cycles. Then there is the cost for reading pfmemalloc out
of the head page which can be cache cold due to the fact that
put_page_testzero is likely invalidating the cache-line on one or more
CPUs as the fragments can be shared.
To avoid this extra expense I have added a pfmemalloc member to the
netdev_alloc_cache. I then pushed pieces of __alloc_rx_skb into
__napi_alloc_skb and __netdev_alloc_skb so that I could rewrite them to
make use of the cached pfmemalloc value. The result is that my perf traces
show a reduction from 9.28% overhead to 3.7% for the code covered by
build_skb, __alloc_rx_skb, and __napi_alloc_skb when performing a test with
the packet being dropped instead of being handed to napi_gro_receive.
Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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