From: Richard Weinberger <richard@nod.at>
To: xenomai@lists.linux.dev
Cc: wg@denx.de, rpm@xenomai.org, Richard Weinberger <richard@nod.at>
Subject: [PATCH] cobalt/drvlib: Prefault io memory again
Date: Tue, 5 Dec 2023 21:22:10 +0100 [thread overview]
Message-ID: <20231205202210.25477-1-richard@nod.at> (raw)
This issue was fixed a long time ago by
03d5b0b0083c ("cobalt/rtdm: fix caching and page fault issues with rtdm_iomap_to_user()"),
later with commit c8e9e166b ("cobalt/rtdm: introduce mmap() support")
iomap code lost again the call to cobalt_machine.prefault().
I have no idea why this took so longer to come up again.
Last week, while upgrading an aarch32 setup from Xenomai 2 to Xenomai 3, the application
failed due to massive latencies caused by page faults after writing to io memory.
Signed-off-by: Richard Weinberger <richard@nod.at>
---
kernel/cobalt/rtdm/drvlib.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/kernel/cobalt/rtdm/drvlib.c b/kernel/cobalt/rtdm/drvlib.c
index 30455c3d7..620be27fa 100644
--- a/kernel/cobalt/rtdm/drvlib.c
+++ b/kernel/cobalt/rtdm/drvlib.c
@@ -1761,6 +1761,7 @@ static int mmap_iomem_helper(struct vm_area_struct *vma, phys_addr_t pa)
{
pgprot_t prot = PAGE_SHARED;
unsigned long len;
+ int ret;
len = vma->vm_end - vma->vm_start;
#ifndef CONFIG_MMU
@@ -1774,8 +1775,17 @@ static int mmap_iomem_helper(struct vm_area_struct *vma, phys_addr_t pa)
#endif
vma->vm_page_prot = pgprot_noncached(prot);
- return remap_pfn_range(vma, vma->vm_start, pa >> PAGE_SHIFT,
- len, vma->vm_page_prot);
+ ret = remap_pfn_range(vma, vma->vm_start, pa >> PAGE_SHIFT,
+ len, vma->vm_page_prot);
+ if (ret)
+ return ret;
+
+#ifdef CONFIG_MMU
+ if (cobalt_machine.prefault)
+ cobalt_machine.prefault(vma);
+#endif
+
+ return 0;
}
static int mmap_buffer_helper(struct rtdm_fd *fd, struct vm_area_struct *vma)
--
2.35.3
next reply other threads:[~2023-12-05 20:29 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-05 20:22 Richard Weinberger [this message]
2023-12-07 9:12 ` [PATCH] cobalt/drvlib: Prefault io memory again Jan Kiszka
2024-01-16 8:22 ` Richard Weinberger
2024-01-22 13:14 ` Philippe Gerum
2024-02-14 14:27 ` Jan Kiszka
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