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From: Dylan Yudaken <dylany@fb.com>
To: Akinobu Mita <akinobu.mita@gmail.com>,
	Jonathan Corbet <corbet@lwn.net>, <linux-doc@vger.kernel.org>
Cc: Dylan Yudaken <dylany@fb.com>
Subject: [PATCH v2] docs: fault-injection: fix defaults
Date: Tue, 5 Apr 2022 02:54:14 -0700	[thread overview]
Message-ID: <20220405095414.816060-1-dylany@fb.com> (raw)

ignore-gfp-wait and ignore-gfp-highmem defaults are actually true (Y) in
both failslab and fail_page_alloc, not false as the docs suggest. See
page_alloc.c:3762 and failslab.c:13

At the same time use 'Y' instead of '1' in the example scripts just for
consistency. (though 1 would work)

Signed-off-by: Dylan Yudaken <dylany@fb.com>
---

v2: reword the docs to explain what happens if 'N' is set.

 Documentation/fault-injection/fault-injection.rst | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/Documentation/fault-injection/fault-injection.rst b/Documentation/fault-injection/fault-injection.rst
index 4a25c5eb6f07..eb9c2d9a4f5f 100644
--- a/Documentation/fault-injection/fault-injection.rst
+++ b/Documentation/fault-injection/fault-injection.rst
@@ -132,16 +132,16 @@ configuration of fault-injection capabilities.
 
 	Format: { 'Y' | 'N' }
 
-	default is 'N', setting it to 'Y' won't inject failures into
-	highmem/user allocations.
+	default is 'Y', setting it to 'N' will also inject failures into
+	highmem/user allocations (__GFP_HIGHMEM allocations).
 
 - /sys/kernel/debug/failslab/ignore-gfp-wait:
 - /sys/kernel/debug/fail_page_alloc/ignore-gfp-wait:
 
 	Format: { 'Y' | 'N' }
 
-	default is 'N', setting it to 'Y' will inject failures
-	only into non-sleep allocations (GFP_ATOMIC allocations).
+	default is 'Y', setting it to 'N' will also inject failures
+	into allocations that can sleep (__GFP_DIRECT_RECLAIM allocations).
 
 - /sys/kernel/debug/fail_page_alloc/min-order:
 
@@ -280,7 +280,7 @@ Application Examples
     printf %#x -1 > /sys/kernel/debug/$FAILTYPE/times
     echo 0 > /sys/kernel/debug/$FAILTYPE/space
     echo 2 > /sys/kernel/debug/$FAILTYPE/verbose
-    echo 1 > /sys/kernel/debug/$FAILTYPE/ignore-gfp-wait
+    echo Y > /sys/kernel/debug/$FAILTYPE/ignore-gfp-wait
 
     faulty_system()
     {
@@ -334,8 +334,8 @@ Application Examples
     printf %#x -1 > /sys/kernel/debug/$FAILTYPE/times
     echo 0 > /sys/kernel/debug/$FAILTYPE/space
     echo 2 > /sys/kernel/debug/$FAILTYPE/verbose
-    echo 1 > /sys/kernel/debug/$FAILTYPE/ignore-gfp-wait
-    echo 1 > /sys/kernel/debug/$FAILTYPE/ignore-gfp-highmem
+    echo Y > /sys/kernel/debug/$FAILTYPE/ignore-gfp-wait
+    echo Y > /sys/kernel/debug/$FAILTYPE/ignore-gfp-highmem
     echo 10 > /sys/kernel/debug/$FAILTYPE/stacktrace-depth
 
     trap "echo 0 > /sys/kernel/debug/$FAILTYPE/probability" SIGINT SIGTERM EXIT
-- 
2.30.2


             reply	other threads:[~2022-04-05 11:07 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-05  9:54 Dylan Yudaken [this message]
2022-04-07  2:23 ` [PATCH v2] docs: fault-injection: fix defaults Akinobu Mita
2022-04-16  8:47   ` Jonathan Corbet

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