From: "Jonathan Lemon" <jonathan.lemon@gmail.com>
To: "Ivan Khoronzhuk" <ivan.khoronzhuk@linaro.org>
Cc: magnus.karlsson@intel.com, bjorn.topel@intel.com,
davem@davemloft.net, hawk@kernel.org, john.fastabend@gmail.com,
jakub.kicinski@netronome.com, daniel@iogearbox.net,
netdev@vger.kernel.org, bpf@vger.kernel.org,
xdp-newbies@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH bpf-next 2/3] xdp: xdp_umem: replace kmap on vmap for umem map
Date: Tue, 13 Aug 2019 11:33:18 -0700 [thread overview]
Message-ID: <BC98A490-2892-452B-AC3E-C9B9F9BA121C@gmail.com> (raw)
In-Reply-To: <20190813183023.GA2856@khorivan>
On 13 Aug 2019, at 11:30, Ivan Khoronzhuk wrote:
> On Tue, Aug 13, 2019 at 10:42:18AM -0700, Jonathan Lemon wrote:
>>
>>
>> On 13 Aug 2019, at 3:23, Ivan Khoronzhuk wrote:
>>
>>> For 64-bit there is no reason to use vmap/vunmap, so use
>>> page_address
>>> as it was initially. For 32 bits, in some apps, like in samples
>>> xdpsock_user.c when number of pgs in use is quite big, the kmap
>>> memory can be not enough, despite on this, kmap looks like is
>>> deprecated in such cases as it can block and should be used rather
>>> for dynamic mm.
>>>
>>> Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
>>
>> Seems a bit overkill - if not high memory, kmap() falls back
>> to just page_address(), unlike vmap().
>
>> -- Jonathan
>
> So, as kmap has limitation... if I correctly understood, you propose
> to avoid macros and do smth like kmap:
>
> void *addr;
> if (!PageHighMem(&umem->pgs[i]))
> addr = page_address(page);
> else
> addr = vmap(&umem->pgs[i], 1, VM_MAP, PAGE_KERNEL);
>
> umem->pages[i].addr = addr;
>
> and while unmap
>
> if (!PageHighMem(&umem->pgs[i]))
> vunmap(umem->pages[i].addr);
>
> I can try it, and add this in v2 if no objection.
Seems like a reasonable compromise to me.
--
Jonathan
>
>>
>>> ---
>>> net/xdp/xdp_umem.c | 16 ++++++++++++----
>>> 1 file changed, 12 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c
>>> index a0607969f8c0..907c9019fe21 100644
>>> --- a/net/xdp/xdp_umem.c
>>> +++ b/net/xdp/xdp_umem.c
>>> @@ -14,7 +14,7 @@
>>> #include <linux/netdevice.h>
>>> #include <linux/rtnetlink.h>
>>> #include <linux/idr.h>
>>> -#include <linux/highmem.h>
>>> +#include <linux/vmalloc.h>
>>>
>>> #include "xdp_umem.h"
>>> #include "xsk_queue.h"
>>> @@ -167,10 +167,12 @@ void xdp_umem_clear_dev(struct xdp_umem *umem)
>>>
>>> static void xdp_umem_unmap_pages(struct xdp_umem *umem)
>>> {
>>> +#if BITS_PER_LONG == 32
>>> unsigned int i;
>>>
>>> for (i = 0; i < umem->npgs; i++)
>>> - kunmap(umem->pgs[i]);
>>> + vunmap(umem->pages[i].addr);
>>> +#endif
>>> }
>>>
>>> static void xdp_umem_unpin_pages(struct xdp_umem *umem)
>>> @@ -378,8 +380,14 @@ static int xdp_umem_reg(struct xdp_umem *umem,
>>> struct xdp_umem_reg *mr)
>>> goto out_account;
>>> }
>>>
>>> - for (i = 0; i < umem->npgs; i++)
>>> - umem->pages[i].addr = kmap(umem->pgs[i]);
>>> + for (i = 0; i < umem->npgs; i++) {
>>> +#if BITS_PER_LONG == 32
>>> + umem->pages[i].addr = vmap(&umem->pgs[i], 1, VM_MAP,
>>> + PAGE_KERNEL);
>>> +#else
>>> + umem->pages[i].addr = page_address(umem->pgs[i]);
>>> +#endif
>>> + }
>>>
>>> return 0;
>>>
>>> --
>>> 2.17.1
>
> --
> Regards,
> Ivan Khoronzhuk
next prev parent reply other threads:[~2019-08-13 18:33 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-13 10:23 [PATCH bpf-next 0/3] xdpsock: allow mmap2 usage for 32bits Ivan Khoronzhuk
2019-08-13 10:23 ` [PATCH bpf-next 1/3] libbpf: add asm/unistd.h to xsk to get __NR_mmap2 Ivan Khoronzhuk
2019-08-13 17:36 ` Jonathan Lemon
2019-08-13 23:38 ` Andrii Nakryiko
2019-08-14 9:24 ` Ivan Khoronzhuk
2019-08-14 11:57 ` Ivan Khoronzhuk
2019-08-14 13:32 ` Björn Töpel
2019-08-14 16:17 ` Yonghong Song
2019-08-14 19:54 ` Ivan Khoronzhuk
2019-08-14 15:51 ` Yonghong Song
2019-08-14 19:56 ` Andrii Nakryiko
2019-08-14 0:32 ` Yonghong Song
2019-08-14 10:19 ` Ivan Khoronzhuk
2019-08-13 10:23 ` [PATCH bpf-next 2/3] xdp: xdp_umem: replace kmap on vmap for umem map Ivan Khoronzhuk
2019-08-13 17:42 ` Jonathan Lemon
2019-08-13 18:30 ` Ivan Khoronzhuk
2019-08-13 18:33 ` Jonathan Lemon [this message]
2019-08-13 10:23 ` [PATCH bpf-next 3/3] samples: bpf: syscal_nrs: use mmap2 if defined Ivan Khoronzhuk
2019-08-13 17:41 ` Jonathan Lemon
2019-08-13 18:59 ` Ivan Khoronzhuk
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