linux-kernel - [patch 1/6] arch: mm: remove obsolete init OOM protection

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Message-Id: <1374791138-15665-2-git-send-email-hannes@cmpxchg.org>
Date:	Thu, 25 Jul 2013 18:25:33 -0400
From:	Johannes Weiner <hannes@...xchg.org>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Michal Hocko <mhocko@...e.cz>,
	David Rientjes <rientjes@...gle.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	azurIt <azurit@...ox.sk>, linux-mm@...ck.org,
	cgroups@...r.kernel.org, x86@...nel.org,
	linux-arch@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [patch 1/6] arch: mm: remove obsolete init OOM protection

Back before smart OOM killing, when faulting tasks where killed
directly on allocation failures, the arch-specific fault handlers
needed special protection for the init process.

Now that all fault handlers call into the generic OOM killer (609838c
"mm: invoke oom-killer from remaining unconverted page fault
handlers"), which already provides init protection, the arch-specific
leftovers can be removed.

Signed-off-by: Johannes Weiner <hannes@...xchg.org>
---
 arch/arc/mm/fault.c   | 5 -----
 arch/score/mm/fault.c | 6 ------
 arch/tile/mm/fault.c  | 6 ------
 3 files changed, 17 deletions(-)

diff --git a/arch/arc/mm/fault.c b/arch/arc/mm/fault.c
index 0fd1f0d..6b0bb41 100644
--- a/arch/arc/mm/fault.c
+++ b/arch/arc/mm/fault.c
@@ -122,7 +122,6 @@ good_area:
 			goto bad_area;
 	}
 
-survive:
 	/*
 	 * If for any reason at all we couldn't handle the fault,
 	 * make sure we exit gracefully rather than endlessly redo
@@ -201,10 +200,6 @@ no_context:
 	die("Oops", regs, address);
 
 out_of_memory:
-	if (is_global_init(tsk)) {
-		yield();
-		goto survive;
-	}
 	up_read(&mm->mmap_sem);
 
 	if (user_mode(regs)) {
diff --git a/arch/score/mm/fault.c b/arch/score/mm/fault.c
index 6b18fb0..4b71a62 100644
--- a/arch/score/mm/fault.c
+++ b/arch/score/mm/fault.c
@@ -100,7 +100,6 @@ good_area:
 			goto bad_area;
 	}
 
-survive:
 	/*
 	* If for any reason at all we couldn't handle the fault,
 	* make sure we exit gracefully rather than endlessly redo
@@ -167,11 +166,6 @@ no_context:
 	*/
 out_of_memory:
 	up_read(&mm->mmap_sem);
-	if (is_global_init(tsk)) {
-		yield();
-		down_read(&mm->mmap_sem);
-		goto survive;
-	}
 	if (!user_mode(regs))
 		goto no_context;
 	pagefault_out_of_memory();
diff --git a/arch/tile/mm/fault.c b/arch/tile/mm/fault.c
index f7f99f9..ac553ee 100644
--- a/arch/tile/mm/fault.c
+++ b/arch/tile/mm/fault.c
@@ -430,7 +430,6 @@ good_area:
 			goto bad_area;
 	}
 
- survive:
 	/*
 	 * If for any reason at all we couldn't handle the fault,
 	 * make sure we exit gracefully rather than endlessly redo
@@ -568,11 +567,6 @@ no_context:
  */
 out_of_memory:
 	up_read(&mm->mmap_sem);
-	if (is_global_init(tsk)) {
-		yield();
-		down_read(&mm->mmap_sem);
-		goto survive;
-	}
 	if (is_kernel_mode)
 		goto no_context;
 	pagefault_out_of_memory();
-- 
1.8.3.2

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