From: Richard Henderson <richard.henderson@linaro.org>
To: Wei Yang <richardw.yang@linux.intel.com>
Cc: fam@euphon.net, mst@redhat.com, mark.cave-ayland@ilande.co.uk,
qemu-devel@nongnu.org, kraxel@redhat.com, den@openvz.org,
qemu-block@nongnu.org, quintela@redhat.com, armbru@redhat.com,
pasic@linux.ibm.com, borntraeger@de.ibm.com,
marcandre.lureau@redhat.com, ehabkost@redhat.com, sw@weilnetz.de,
dgilbert@redhat.com, yuval.shaia@oracle.com,
alex.williamson@redhat.com, stefanha@redhat.com,
pbonzini@redhat.com, david@gibson.dropbear.id.au,
kwolf@redhat.com, cohuck@redhat.com, qemu-s390x@nongnu.org,
mreitz@redhat.com, qemu-ppc@nongnu.org, imammedo@redhat.com
Subject: Re: [PATCH 1/2] cpu: use ROUND_UP() to define xxx_PAGE_ALIGN
Date: Sun, 13 Oct 2019 19:38:04 -0700 [thread overview]
Message-ID: <4036820a-f357-9e67-7e58-cbb9186d0ef4@linaro.org> (raw)
In-Reply-To: <20191014010142.GA29752@richard>
On 10/13/19 6:01 PM, Wei Yang wrote:
>> No, please.
>>
>> (1) The compiler does not know that qemu_*host_page_size is a power of 2, and
>> will generate a real division at runtime. The same is true for
>> TARGET_PAGE_SIZE when TARGET_PAGE_BITS_VARY.
>>
>
> Confused
>
> The definition of ROUND_UP is:
>
> #define ROUND_UP(n, d) (((n) + (d) - 1) & -(0 ? (n) : (d)))
Ah, my bad, I did confuse this with QEMU_ALIGN_UP.
Hmm.
lea -1(n, size), t
neg size
and size, t
vs
mov mask, t
not t
add n, t
and mask, t
which is what I proposed here
>> https://lists.gnu.org/archive/html/qemu-devel/2019-09/msg04526.html
I'm ok with your version.
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
r~
next prev parent reply other threads:[~2019-10-14 2:39 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-13 2:11 [PATCH 0/2] cleanup on page size Wei Yang
2019-10-13 2:11 ` [PATCH 1/2] cpu: use ROUND_UP() to define xxx_PAGE_ALIGN Wei Yang
2019-10-13 6:34 ` Michael S. Tsirkin
2019-10-13 9:27 ` David Gibson
2019-10-13 15:56 ` Richard Henderson
2019-10-13 23:36 ` David Gibson
2019-10-14 1:01 ` Wei Yang
2019-10-14 2:38 ` Richard Henderson [this message]
2019-10-14 3:19 ` Wei Yang
2019-10-14 16:25 ` Juan Quintela
2019-10-13 2:11 ` [PATCH 2/2] core: replace getpagesize() with qemu_real_host_page_size Wei Yang
2019-10-13 6:35 ` Michael S. Tsirkin
2019-10-13 9:28 ` David Gibson
2019-10-16 1:25 ` Wei Yang
2019-10-13 16:03 ` Richard Henderson
2019-10-14 9:15 ` Dr. David Alan Gilbert
2019-10-14 21:36 ` Wei Yang
2019-10-14 23:12 ` Richard Henderson
2019-10-15 11:45 ` Yuval Shaia
2019-10-16 1:07 ` Wei Yang
2019-10-23 9:19 ` Paolo Bonzini
2019-10-13 6:36 ` [PATCH 0/2] cleanup on page size Michael S. Tsirkin
2019-10-14 21:59 ` Wei Yang
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