Re: [PATCH tty-next 5/7] n_tty: Refactor input_available_p() by call site
On Sat, 23 Nov 2013 21:01:56 -0500 Peter Hurley wrote: > On 11/23/2013 07:26 PM, One Thousand Gnomes wrote: > > On Fri, 22 Nov 2013 10:59:23 -0500 > > Peter Hurley wrote: > > > >> Distinguish if caller is n_tty_poll() or n_tty_read(), and > >> set the read/wakeup threshold accordingly. > >> > >> Signed-off-by: Peter Hurley > > > > Doh ignore previous.. yes that patch is right. I should pay attention to > > 0/7 8) > > Maybe I should add more to the commit message from the cover letter > description ? Maybe I should just read the code more carefully 8). Alan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH tty-next 5/7] n_tty: Refactor input_available_p() by call site
On Sat, 23 Nov 2013 21:01:56 -0500 Peter Hurley pe...@hurleysoftware.com wrote: On 11/23/2013 07:26 PM, One Thousand Gnomes wrote: On Fri, 22 Nov 2013 10:59:23 -0500 Peter Hurley pe...@hurleysoftware.com wrote: Distinguish if caller is n_tty_poll() or n_tty_read(), and set the read/wakeup threshold accordingly. Signed-off-by: Peter Hurley pe...@hurleysoftware.com Doh ignore previous.. yes that patch is right. I should pay attention to 0/7 8) Maybe I should add more to the commit message from the cover letter description ? Maybe I should just read the code more carefully 8). Alan -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH tty-next 5/7] n_tty: Refactor input_available_p() by call site
On 11/23/2013 07:26 PM, One Thousand Gnomes wrote: On Fri, 22 Nov 2013 10:59:23 -0500 Peter Hurley wrote: Distinguish if caller is n_tty_poll() or n_tty_read(), and set the read/wakeup threshold accordingly. Signed-off-by: Peter Hurley Doh ignore previous.. yes that patch is right. I should pay attention to 0/7 8) Maybe I should add more to the commit message from the cover letter description ? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH tty-next 5/7] n_tty: Refactor input_available_p() by call site
On Fri, 22 Nov 2013 10:59:23 -0500 Peter Hurley wrote: > Distinguish if caller is n_tty_poll() or n_tty_read(), and > set the read/wakeup threshold accordingly. > > Signed-off-by: Peter Hurley Doh ignore previous.. yes that patch is right. I should pay attention to 0/7 8) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH tty-next 5/7] n_tty: Refactor input_available_p() by call site
On Fri, 22 Nov 2013 10:59:23 -0500
Peter Hurley wrote:
> Distinguish if caller is n_tty_poll() or n_tty_read(), and
> set the read/wakeup threshold accordingly.
That looks very wrong to me. The poll() and read() wakeup should always
match. In addition if MIN_CHAR is set without a timeout then it should not
wake up until MIN_CHAR characters are present. The MIN_CHAR feature is
used by various (these days obscure) protocols to optimise block transfer
rates.
Changing this is also a userspace visible API change.
So NAK.
The underlying intention of the system (and SYS5.4) is that you can do
MIN_CHAR = 64
alarm(some_timeout)
while(1) {
poll();
events
read(chunksized blocks)
}
while it's hardly as critical with modern fast hardware its still the API
and necessary to avoid SWS type behaviours in the queue turning it from
block/syscall to byte I/O.
Alan
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Re: [PATCH tty-next 5/7] n_tty: Refactor input_available_p() by call site
On Fri, 22 Nov 2013 10:59:23 -0500
Peter Hurley pe...@hurleysoftware.com wrote:
Distinguish if caller is n_tty_poll() or n_tty_read(), and
set the read/wakeup threshold accordingly.
That looks very wrong to me. The poll() and read() wakeup should always
match. In addition if MIN_CHAR is set without a timeout then it should not
wake up until MIN_CHAR characters are present. The MIN_CHAR feature is
used by various (these days obscure) protocols to optimise block transfer
rates.
Changing this is also a userspace visible API change.
So NAK.
The underlying intention of the system (and SYS5.4) is that you can do
MIN_CHAR = 64
alarm(some_timeout)
while(1) {
poll();
events
read(chunksized blocks)
}
while it's hardly as critical with modern fast hardware its still the API
and necessary to avoid SWS type behaviours in the queue turning it from
block/syscall to byte I/O.
Alan
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To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH tty-next 5/7] n_tty: Refactor input_available_p() by call site
On Fri, 22 Nov 2013 10:59:23 -0500 Peter Hurley pe...@hurleysoftware.com wrote: Distinguish if caller is n_tty_poll() or n_tty_read(), and set the read/wakeup threshold accordingly. Signed-off-by: Peter Hurley pe...@hurleysoftware.com Doh ignore previous.. yes that patch is right. I should pay attention to 0/7 8) -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH tty-next 5/7] n_tty: Refactor input_available_p() by call site
On 11/23/2013 07:26 PM, One Thousand Gnomes wrote: On Fri, 22 Nov 2013 10:59:23 -0500 Peter Hurley pe...@hurleysoftware.com wrote: Distinguish if caller is n_tty_poll() or n_tty_read(), and set the read/wakeup threshold accordingly. Signed-off-by: Peter Hurley pe...@hurleysoftware.com Doh ignore previous.. yes that patch is right. I should pay attention to 0/7 8) Maybe I should add more to the commit message from the cover letter description ? -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH tty-next 5/7] n_tty: Refactor input_available_p() by call site
Distinguish if caller is n_tty_poll() or n_tty_read(), and
set the read/wakeup threshold accordingly.
Signed-off-by: Peter Hurley
---
drivers/tty/n_tty.c | 7 ---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 9298b68..8f2356e 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -1878,14 +1878,15 @@ static int n_tty_open(struct tty_struct *tty)
return 0;
}
-static inline int input_available_p(struct tty_struct *tty, int amt)
+static inline int input_available_p(struct tty_struct *tty, int poll)
{
struct n_tty_data *ldata = tty->disc_data;
+ int amt = poll && !TIME_CHAR(tty) ? MIN_CHAR(tty) : 1;
if (ldata->icanon && !L_EXTPROC(tty)) {
if (ldata->canon_head != ldata->read_tail)
return 1;
- } else if (read_cnt(ldata) >= (amt ? amt : 1))
+ } else if (read_cnt(ldata) >= amt)
return 1;
return 0;
@@ -2384,7 +2385,7 @@ static unsigned int n_tty_poll(struct tty_struct *tty,
struct file *file,
poll_wait(file, >read_wait, wait);
poll_wait(file, >write_wait, wait);
- if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty)))
+ if (input_available_p(tty, 1))
mask |= POLLIN | POLLRDNORM;
else if (ldata->icanon)
n_tty_set_room(tty);
--
1.8.1.2
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[PATCH tty-next 5/7] n_tty: Refactor input_available_p() by call site
Distinguish if caller is n_tty_poll() or n_tty_read(), and
set the read/wakeup threshold accordingly.
Signed-off-by: Peter Hurley pe...@hurleysoftware.com
---
drivers/tty/n_tty.c | 7 ---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 9298b68..8f2356e 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -1878,14 +1878,15 @@ static int n_tty_open(struct tty_struct *tty)
return 0;
}
-static inline int input_available_p(struct tty_struct *tty, int amt)
+static inline int input_available_p(struct tty_struct *tty, int poll)
{
struct n_tty_data *ldata = tty-disc_data;
+ int amt = poll !TIME_CHAR(tty) ? MIN_CHAR(tty) : 1;
if (ldata-icanon !L_EXTPROC(tty)) {
if (ldata-canon_head != ldata-read_tail)
return 1;
- } else if (read_cnt(ldata) = (amt ? amt : 1))
+ } else if (read_cnt(ldata) = amt)
return 1;
return 0;
@@ -2384,7 +2385,7 @@ static unsigned int n_tty_poll(struct tty_struct *tty,
struct file *file,
poll_wait(file, tty-read_wait, wait);
poll_wait(file, tty-write_wait, wait);
- if (input_available_p(tty, TIME_CHAR(tty) ? 0 : MIN_CHAR(tty)))
+ if (input_available_p(tty, 1))
mask |= POLLIN | POLLRDNORM;
else if (ldata-icanon)
n_tty_set_room(tty);
--
1.8.1.2
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