From: Alexander Duyck <alexander.duyck@gmail.com>
To: David Miller <davem@davemloft.net>, alexander.h.duyck@redhat.com
Cc: netdev@vger.kernel.org, linux-mm@kvack.org,
akpm@linux-foundation.org, eric.dumazet@gmail.com
Subject: Re: [PATCH 01/10] net: Use cached copy of pfmemalloc to avoid accessing page
Date: Sun, 10 May 2015 17:01:15 -0700 [thread overview]
Message-ID: <554FF14B.4050901@gmail.com> (raw)
In-Reply-To: <20150510.191851.414324528131774160.davem@davemloft.net>
On 05/10/2015 04:18 PM, David Miller wrote:
> From: Alexander Duyck <alexander.h.duyck@redhat.com>
> Date: Wed, 06 May 2015 21:11:40 -0700
>
>> + /* use OR instead of assignment to avoid clearing of bits in mask */
>> + if (pfmemalloc)
>> + skb->pfmemalloc = 1;
>> + skb->head_frag = 1;
> ...
>> + /* use OR instead of assignment to avoid clearing of bits in mask */
>> + if (nc->pfmemalloc)
>> + skb->pfmemalloc = 1;
>> + skb->head_frag = 1;
> Maybe make these two cases more consistent by either accessing
> nc->pfmemalloc or using a local variable in both cases.
The only option would be to use a local variable in both cases, but then
I am still stuck with the differences in when I can access the caches.
The reason for the difference between the two is that in the case of
netdev_alloc_skb/frag the netdev_alloc_cache can only be accessed with
IRQs disabled, whereas in the napi_alloc_skb case we can access the
napi_alloc_cache at any point in the function. Either way I am going to
be stuck with differences because of the local_irq_save/restore that
must be called when accessing the page frag cache that doesn't exist in
the napi case.
- Alex
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next prev parent reply other threads:[~2015-05-11 0:01 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-07 4:11 [PATCH 00/10] Refactor netdev page frags and move them into mm/ Alexander Duyck
2015-05-07 4:11 ` [PATCH 01/10] net: Use cached copy of pfmemalloc to avoid accessing page Alexander Duyck
2015-05-10 23:18 ` David Miller
2015-05-11 0:01 ` Alexander Duyck [this message]
2015-05-11 0:52 ` David Miller
2015-05-07 4:11 ` [PATCH 02/10] igb: Don't use NETDEV_FRAG_PAGE_MAX_SIZE in descriptor calculation Alexander Duyck
2015-05-07 4:11 ` [PATCH 03/10] net: Store virtual address instead of page in netdev_alloc_cache Alexander Duyck
2015-05-07 4:11 ` [PATCH 04/10] mm/net: Rename and move page fragment handling from net/ to mm/ Alexander Duyck
2015-05-07 4:12 ` [PATCH 05/10] net: Add skb_free_frag to replace use of put_page in freeing skb->head Alexander Duyck
2015-05-07 4:12 ` [PATCH 06/10] netcp: Replace put_page(virt_to_head_page(ptr)) w/ skb_free_frag Alexander Duyck
2015-05-07 4:12 ` [PATCH 07/10] mvneta: " Alexander Duyck
2015-05-07 4:12 ` [PATCH 08/10] e1000: Replace e1000_free_frag with skb_free_frag Alexander Duyck
2015-05-07 8:46 ` Jeff Kirsher
2015-05-07 4:12 ` [PATCH 09/10] hisilicon: Replace put_page(virt_to_head_page()) with skb_free_frag() Alexander Duyck
2015-05-07 4:12 ` [PATCH 10/10] bnx2x, tg3: " Alexander Duyck
2015-05-10 23:17 ` [PATCH 00/10] Refactor netdev page frags and move them into mm/ David Miller
2015-05-11 20:36 ` Andrew Morton
2015-05-12 14:39 ` David Miller
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