File 0036-AIO-Reduce-number-of-threads-for-32.patch of Package qemu

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File 0036-AIO-Reduce-number-of-threads-for-32.patch of Package qemu (Revision f22797c578b1baf3d276449b2dc5a06f)

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From dd7584c2d0ffdd72da452681268cf3a9c21e98ee Mon Sep 17 00:00:00 2001
From: Alexander Graf <agraf@suse.de>
Date: Wed, 14 Jan 2015 01:32:11 +0100
Subject: [PATCH] AIO: Reduce number of threads for 32bit hosts

On hosts with limited virtual address space (32bit pointers), we can very
easily run out of virtual memory with big thread pools.

Instead, we should limit ourselves to small pools to keep memory footprint
low on those systems.

This patch fixes random VM stalls like

(process:25114): GLib-ERROR **: gmem.c:103: failed to allocate 1048576 bytes

on 32bit ARM systems for me.

Signed-off-by: Alexander Graf <agraf@suse.de>
---
 thread-pool.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/thread-pool.c b/thread-pool.c
index e2cac8e..87a3ea9 100644
--- a/thread-pool.c
+++ b/thread-pool.c
@@ -299,7 +299,12 @@ static void thread_pool_init_one(ThreadPool *pool, AioContext *ctx)
     qemu_mutex_init(&pool->lock);
     qemu_cond_init(&pool->worker_stopped);
     qemu_sem_init(&pool->sem, 0);
-    pool->max_threads = 64;
+    if (sizeof(pool) == 4) {
+        /* 32bit systems run out of virtual memory quickly */
+        pool->max_threads = 4;
+    } else {
+        pool->max_threads = 64;
+    }
     pool->new_thread_bh = aio_bh_new(ctx, spawn_thread_bh_fn, pool);
 
     QLIST_INIT(&pool->head);

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File 0036-AIO-Reduce-number-of-threads-for-32.patch of Package qemu (Revision f22797c578b1baf3d276449b2dc5a06f)

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