File 0031-AIO-Reduce-number-of-threads-for-32.patch of Package qemu

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File 0031-AIO-Reduce-number-of-threads-for-32.patch of Package qemu (Revision b707be899935af742c5efb268ec4bb00)

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From 4aa17b7cf5d35e03c2e563477e920cd7104d5806 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 6fba913..ee0b485 100644
--- a/thread-pool.c
+++ b/thread-pool.c
@@ -297,7 +297,12 @@ 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 0031-AIO-Reduce-number-of-threads-for-32.patch of Package qemu (Revision b707be899935af742c5efb268ec4bb00)

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