From: Finn Thain <fthain@linux-m68k.org>
To: Michael Schmitz <schmitzmic@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
linux-m68k@lists.linux-m68k.org
Subject: Re: [PATCH RFC] m68k: skip kernel premption if interrupts were disabled
Date: Tue, 26 Mar 2024 20:58:02 +1100 (AEDT) [thread overview]
Message-ID: <c8a063a1-c72c-9aed-65fc-b2d87f8c7a9b@linux-m68k.org> (raw)
In-Reply-To: <597ab0b3-ac1d-443c-95f7-4f1bbcccae1f@gmail.com>
On Tue, 26 Mar 2024, Michael Schmitz wrote:
> see below (hopefully not whitespace-damaged).
>
Following your approach, I added mutual exclusion to the other candidate
in the same file, namely get_pointer_table(). Together with your patch,
that seems to be sufficient to make stress-ng happy. I don't know the real
extent of the data race here so I've probably used too much locking in
this experiment (?)
diff --git a/arch/m68k/mm/motorola.c b/arch/m68k/mm/motorola.c
index 068ad7c9bb5c..d1ad55ee1b60 100644
--- a/arch/m68k/mm/motorola.c
+++ b/arch/m68k/mm/motorola.c
@@ -140,10 +140,14 @@ void __init init_pointer_table(void *table, int type)
void *get_pointer_table(int type)
{
- ptable_desc *dp = ptable_list[type].next;
- unsigned int mask = list_empty(&ptable_list[type]) ? 0 : PD_MARKBITS(dp);
+ ptable_desc *dp;
+ unsigned int mask;
unsigned int tmp, off;
+ preempt_disable();
+
+ dp = ptable_list[type].next;
+ mask = list_empty(&ptable_list[type]) ? 0 : PD_MARKBITS(dp);
/*
* For a pointer table for a user process address space, a
* table is taken from a page allocated for the purpose. Each
@@ -154,8 +158,13 @@ void *get_pointer_table(int type)
void *page;
ptable_desc *new;
- if (!(page = (void *)get_zeroed_page(GFP_KERNEL)))
+ sched_preempt_enable_no_resched();
+
+ if (!(page = (void *)get_zeroed_page(GFP_KERNEL))) {
return NULL;
+ }
+
+ preempt_disable();
if (type == TABLE_PTE) {
/*
@@ -171,6 +180,7 @@ void *get_pointer_table(int type)
PD_MARKBITS(new) = ptable_mask(type) - 1;
list_add_tail(new, dp);
+ sched_preempt_enable_no_resched();
return (pmd_t *)page;
}
@@ -181,6 +191,7 @@ void *get_pointer_table(int type)
/* move to end of list */
list_move_tail(dp, &ptable_list[type]);
}
+ sched_preempt_enable_no_resched();
return page_address(PD_PAGE(dp)) + off;
}
next prev parent reply other threads:[~2024-03-26 9:56 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-22 1:48 [PATCH RFC] m68k: skip kernel premption if interrupts were disabled Michael Schmitz
[not found] ` <fcabda73-4b16-ee2c-e993-2bfcf392a26a@linux-m68k.org>
[not found] ` <e89bf618-2fa8-7cbd-16ed-d021a9a7f740@gmail.com>
[not found] ` <948c12e4-e85f-a86c-ae95-a1eb03ca026d@gmail.com>
[not found] ` <40928e38-0de7-75a6-d5f7-8c913155da03@linux-m68k.org>
2024-03-23 6:32 ` Michael Schmitz
2024-03-25 6:41 ` Michael Schmitz
2024-03-25 22:28 ` Finn Thain
2024-03-25 22:31 ` Michael Schmitz
2024-03-26 0:41 ` Finn Thain
2024-03-26 9:58 ` Finn Thain [this message]
2024-03-26 19:59 ` Michael Schmitz
2024-03-26 22:03 ` Finn Thain
2024-03-26 22:35 ` Michael Schmitz
2024-03-27 3:50 ` Finn Thain
2024-03-27 6:56 ` Michael Schmitz
2024-03-27 23:29 ` Spinlock debug, was " Finn Thain
[not found] ` <7aee9fd9-1c0e-4874-bb86-e512a7c0caa6@gmail.com>
2024-03-28 2:48 ` Finn Thain
2024-03-28 19:54 ` Michael Schmitz
2024-03-30 2:46 ` Michael Schmitz
2024-03-30 6:23 ` Finn Thain
2024-03-31 6:14 ` Michael Schmitz
2024-03-27 8:38 ` Finn Thain
2024-03-27 22:59 ` Michael Schmitz
2024-03-27 8:22 ` Geert Uytterhoeven
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