From: Jan Beulich <jbeulich@suse.com>
To: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Cc: "Andrew Cooper" <andrew.cooper3@citrix.com>,
"George Dunlap" <george.dunlap@citrix.com>,
"Wei Liu" <wl@xen.org>, "Roger Pau Monné" <roger.pau@citrix.com>
Subject: [PATCH v2 4/8] x86/IRQ: avoid over-alignment in alloc_pirq_struct()
Date: Wed, 21 Apr 2021 16:57:27 +0200 [thread overview]
Message-ID: <8906088c-d76a-12ac-31d3-1375016a2148@suse.com> (raw)
In-Reply-To: <091b4b91-712f-3526-78d1-80d31faf8e41@suse.com>
In particular in the PV case xzalloc_bytes() forcing SMP_CACHE_BYTES
alignment is counterproductive, as the allocation size there is only 40
bytes. And if the code really cared about such higher than default
alignment, it should request so explicitly rather than using a type-
unsafe interface. Plus if e.g. cache line sharing was a concern, the
allocator itself should arrange to avoid such.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/xen/arch/x86/irq.c
+++ b/xen/arch/x86/irq.c
@@ -1313,9 +1313,12 @@ void cleanup_domain_irq_mapping(struct d
struct pirq *alloc_pirq_struct(struct domain *d)
{
- size_t sz = is_hvm_domain(d) ? sizeof(struct pirq) :
- offsetof(struct pirq, arch.hvm);
- struct pirq *pirq = xzalloc_bytes(sz);
+ union pirq_pv {
+ char space[offsetof(struct pirq, arch.hvm)];
+ void *align;
+ };
+ struct pirq *pirq = is_hvm_domain(d) ? xzalloc(struct pirq)
+ : (void *)xzalloc(union pirq_pv);
if ( pirq )
{
next prev parent reply other threads:[~2021-04-21 14:57 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-21 14:54 [PATCH v2 0/8] assorted replacement of x[mz]alloc_bytes() Jan Beulich
2021-04-21 14:56 ` [PATCH v2 1/8] x86/MCE: avoid effectively open-coding xmalloc_array() Jan Beulich
2021-04-21 14:56 ` [PATCH v2 2/8] x86/HVM: " Jan Beulich
2021-04-21 14:57 ` [PATCH v2 3/8] x86/oprofile: " Jan Beulich
2021-04-21 14:57 ` Jan Beulich [this message]
2021-04-21 14:58 ` [PATCH v2 5/8] EFI/runtime: avoid effectively open-coding x{m,z}alloc_array() Jan Beulich
2021-04-21 14:58 ` [PATCH v2 6/8] kexec: avoid effectively open-coding xzalloc_flex_struct() Jan Beulich
2021-04-21 14:59 ` [PATCH v2 7/8] video/lfb: avoid effectively open-coding xzalloc_array() Jan Beulich
2021-04-21 14:59 ` [PATCH v2 8/8] Arm/optee: don't open-code xzalloc_flex_struct() Jan Beulich
2021-05-03 13:53 ` Ping: " Jan Beulich
2021-05-04 23:49 ` Volodymyr Babchuk
2021-04-21 15:23 ` [PATCH v2 0/8] assorted replacement of x[mz]alloc_bytes() Andrew Cooper
2021-04-21 15:32 ` Jan Beulich
2021-04-23 9:44 ` Jan Beulich
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=8906088c-d76a-12ac-31d3-1375016a2148@suse.com \
--to=jbeulich@suse.com \
--cc=andrew.cooper3@citrix.com \
--cc=george.dunlap@citrix.com \
--cc=roger.pau@citrix.com \
--cc=wl@xen.org \
--cc=xen-devel@lists.xenproject.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).