[PATCH] fbcon: use kvmalloc() for scrollback buffer
Subsystems:
framebuffer console , framebuffer core , framebuffer layer , the rest
2768d
4 messages,
2 authors,
2019-02-08 · open the first message on its own page
Scrollback frame buffer is rather big - 32K,
so it requires 3rd order page, so let's use kvmalloc() instead of
ordinary kmalloc() for it.
Signed-off-by: Konstantin Khorenko <redacted>
---
drivers/video/fbdev/core/fbcon.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
index 8958ccc8b1ac..2b1a34d3f5e2 100644
--- a/drivers/video/fbdev/core/fbcon.c
+++ b/drivers/video/fbdev/core/fbcon.c @@ -992,7 +992,7 @@ static const char *fbcon_startup(void)
if ( ! softback_buf ) {
softback_buf ( unsigned long )
- kmalloc ( fbcon_softback_size , + kvmalloc ( fbcon_softback_size , GFP_KERNEL );
if ( ! softback_buf ) {
fbcon_softback_size = 0 ; @@ -1001,7 +1001,7 @@ static const char *fbcon_startup(void)
}
} else {
if ( softback_buf ) {
- kfree (( void * ) softback_buf ); + kvfree (( void * ) softback_buf ); softback_buf = 0 ;
softback_top = 0 ;
} @@ -3665,7 +3665,7 @@ static void fbcon_exit(void)
}
#endif
- kfree (( void * ) softback_buf ); + kvfree (( void * ) softback_buf ); softback_buf = 0UL ;
for_each_registered_fb ( i ) { --
2.15.1
Hi,
On 11/26/2018 11:02 AM, Konstantin Khorenko wrote: Scrollback frame buffer is rather big - 32K,
so it requires 3rd order page, so let's use kvmalloc() instead of
ordinary kmalloc() for it.
Is it actually safe to use non-contiguous memory for softback_buf?
quoted hunk Signed-off-by: Konstantin Khorenko <redacted>
---
drivers/video/fbdev/core/fbcon.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
index 8958ccc8b1ac..2b1a34d3f5e2 100644
--- a/drivers/video/fbdev/core/fbcon.c
+++ b/drivers/video/fbdev/core/fbcon.c @@ -992,7 +992,7 @@ static const char *fbcon_startup(void)
if ( ! softback_buf ) {
softback_buf > ( unsigned long )
- kmalloc ( fbcon_softback_size , + kvmalloc ( fbcon_softback_size , GFP_KERNEL );
if ( ! softback_buf ) {
fbcon_softback_size = 0 ; @@ -1001,7 +1001,7 @@ static const char *fbcon_startup(void)
}
} else {
if ( softback_buf ) {
- kfree (( void * ) softback_buf ); + kvfree (( void * ) softback_buf ); softback_buf = 0 ;
softback_top = 0 ;
} @@ -3665,7 +3665,7 @@ static void fbcon_exit(void)
}
#endif
- kfree (( void * ) softback_buf ); + kvfree (( void * ) softback_buf ); softback_buf = 0UL ;
for_each_registered_fb ( i ) {
Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics
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On 12/21/2018 11:58 AM, Konstantin Khorenko wrote: Hi Bartlomiej,
On 12/20/2018 07:21 PM, Bartlomiej Zolnierkiewicz wrote: quoted On 11/26/2018 11:02 AM, Konstantin Khorenko wrote: quoted Scrollback frame buffer is rather big - 32K,
so it requires 3rd order page, so let's use kvmalloc() instead of
ordinary kmalloc() for it.
Is it actually safe to use non-contiguous memory for softback_buf?
Well, that's why we need a review. :)
:)
i've asked myself same question while fixing this,
i've dig sources a bit and did not find places when softback_buf is provided for DMA,
all other places seems to work with virtual addresses, so there should be no problem.
Even more i saw a function which mentions that softback might be non-contigious:
/* As we might be inside of softback, we may work with non-contiguous buffer,
that's why we have to use a separate routine. */
static void fbcon_invert_region(struct vc_data *vc, u16 * p, int cnt)
So i think it's safe to use kvmalloc() here.
Patch queued for v5.1, thanks.
Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics