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NAND: Prevents NAND subsystem from hogging the CPU.

PATCH In review Rick Bronson 3 participants 3 messages Sep 6, 2007 – Sep 7, 2007

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Memory technology devices (MTD) NAND flash
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Rick Bronson

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PATCH 1/1 NAND: Prevents NAND subsystem from hogging the CPU.

This is my first patch for mtd so bear with me... sorry if I missed
something.

[PATCH] [MTD] NAND: Prevents NAND subsystem from hogging the CPU waiting for ready line.

This patch prevents the nand_wait_ready chip from using too much CPU time. This was causing very long thread latencies. The solution, which is used elsewhere in this same file, is to call cond_resched() in the wait loop.

[From: Rick Bronson <[email protected]>]
[Acked-by: Realname <realmail>]
Signed-off-by Realname <realmail>
drivers/mtd/nand/nand_base.c 2007-09-06 08:31:20.000000000 -0700 renamed from drivers/mtd/nand/nand_base.c 2007-09-06 07:46:18.000000000 -0700 +1 -0
diff -ruN mtd-2.6.orig/drivers/mtd/nand/nand_base.c mtd-2.6/drivers/mtd/nand/nand_base.c
@@ -429,6 +429,7 @@
                if (chip->dev_ready(mtd))
                        break;
                touch_softlockup_watchdog();
+               cond_resched();  /* let others run */
        } while (time_before(jiffies, timeo));
        led_trigger_event(nand_led_trigger, LED_OFF);
 }
#1 lore raw
Quoted 4 lines · Rick Bronson
[From: Rick Bronson <[email protected]>]
[Acked-by: Realname <realmail>]
Signed-off-by Realname <realmail>

Looks like whatever tool you used needs a bit of configuration.

Jörn

Signature · 4 lines
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#2 lore raw
In reply to Rick Bronson
Quoted 7 lines · Rick Bronson
                if (chip->dev_ready(mtd))
                        break;
                touch_softlockup_watchdog();
+               cond_resched();  /* let others run */
        } while (time_before(jiffies, timeo));
        led_trigger_event(nand_led_trigger, LED_OFF);

}

And I think this touch_softlockup_watchdog() is bogus.

Signature · 2 lines
Best regards,
Artem Bityutskiy (Битюцкий Артём)