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>
Subject: [PATCH 09/11] kexec: avoid effectively open-coding xzalloc_flex_struct()
Date: Thu, 8 Apr 2021 14:21:56 +0200 [thread overview]
Message-ID: <4ea9c4a3-74c0-1722-fa5d-3930be99ef4a@suse.com> (raw)
In-Reply-To: <a3fef3b0-c9f3-208e-3728-62ca9cff70ba@suse.com>
There is a difference in generated code: xzalloc_bytes() forces
SMP_CACHE_BYTES alignment. I think we not only don't need this here, but
actually don't want it.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/xen/common/kexec.c
+++ b/xen/common/kexec.c
@@ -463,7 +463,10 @@ static void * alloc_from_crash_heap(cons
/* Allocate a crash note buffer for a newly onlined cpu. */
static int kexec_init_cpu_notes(const unsigned long cpu)
{
- Elf_Note * note = NULL;
+ struct elf_notes {
+ Elf_Note first;
+ unsigned char more[];
+ } *notes = NULL;
int ret = 0;
int nr_bytes = 0;
@@ -477,7 +480,8 @@ static int kexec_init_cpu_notes(const un
/* If we dont care about the position of allocation, malloc. */
if ( low_crashinfo_mode == LOW_CRASHINFO_NONE )
- note = xzalloc_bytes(nr_bytes);
+ notes = xzalloc_flex_struct(struct elf_notes, more,
+ nr_bytes - sizeof(notes->first));
/* Protect the write into crash_notes[] with a spinlock, as this function
* is on a hotplug path and a hypercall path. */
@@ -490,26 +494,28 @@ static int kexec_init_cpu_notes(const un
spin_unlock(&crash_notes_lock);
/* Always return ok, because whether we successfully allocated or not,
* another CPU has successfully allocated. */
- xfree(note);
+ xfree(notes);
}
else
{
/* If we care about memory possition, alloc from the crash heap,
* also protected by the crash_notes_lock. */
if ( low_crashinfo_mode > LOW_CRASHINFO_NONE )
- note = alloc_from_crash_heap(nr_bytes);
+ notes = alloc_from_crash_heap(nr_bytes);
- crash_notes[cpu].start = note;
+ crash_notes[cpu].start = ¬es->first;
crash_notes[cpu].size = nr_bytes;
spin_unlock(&crash_notes_lock);
/* If the allocation failed, and another CPU did not beat us, give
* up with ENOMEM. */
- if ( ! note )
+ if ( ! notes )
ret = -ENOMEM;
/* else all is good so lets set up the notes. */
else
{
+ Elf_Note *note = ¬es->first;
+
/* Set up CORE note. */
setup_note(note, "CORE", NT_PRSTATUS, sizeof(ELF_Prstatus));
note = ELFNOTE_NEXT(note);
next prev parent reply other threads:[~2021-04-08 12:22 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-08 12:13 [PATCH 00/11] assorted replacement of x[mz]alloc_bytes() Jan Beulich
2021-04-08 12:16 ` [PATCH 01/11] x86/HVM: avoid effectively open-coding xzalloc_flex_struct() Jan Beulich
2021-04-08 12:20 ` Andrew Cooper
2021-04-08 12:17 ` [PATCH 02/11] x86/vPMU: " Jan Beulich
2021-04-08 12:25 ` Andrew Cooper
2021-04-08 12:29 ` Jan Beulich
2021-04-08 12:17 ` [PATCH 03/11] x86/MCE: avoid effectively open-coding xmalloc_array() Jan Beulich
2021-04-08 12:18 ` [PATCH 04/11] x86/HVM: " Jan Beulich
2021-04-08 12:19 ` [PATCH 05/11] x86/oprofile: " Jan Beulich
2021-04-08 12:20 ` [PATCH 06/11] x86/IRQ: avoid over-alignment in alloc_pirq_struct() Jan Beulich
2021-04-08 12:20 ` [PATCH 07/11] EFI/runtime: avoid effectively open-coding xmalloc_array() Jan Beulich
2021-04-08 12:21 ` [PATCH 08/11] hypfs: avoid effectively open-coding xzalloc_array() Jan Beulich
2021-04-08 14:28 ` Juergen Gross
2021-04-08 12:21 ` Jan Beulich [this message]
2021-04-09 12:54 ` [PATCH 09/11] kexec: avoid effectively open-coding xzalloc_flex_struct() Andrew Cooper
2021-04-09 13:23 ` Jan Beulich
2021-04-08 12:22 ` [PATCH 10/11] video/lfb: avoid effectively open-coding xzalloc_array() Jan Beulich
2021-04-08 12:23 ` [PATCH 11/11] Arm/optee: don't open-code xzalloc_flex_struct() Jan Beulich
2021-04-13 18:19 ` Julien Grall
2021-04-14 7:03 ` Jan Beulich
2021-04-15 10:26 ` Julien Grall
2021-04-15 11:02 ` Jan Beulich
2021-04-15 11:31 ` Julien Grall
2021-04-08 12:57 ` [PATCH 00/11] assorted replacement of x[mz]alloc_bytes() Andrew Cooper
2021-04-08 14:12 ` Jan Beulich
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