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From: "Alex Bennée" <alex.bennee@linaro.org>
To: qemu-devel@nongnu.org
Cc: fam@euphon.net, berrange@redhat.com,
	"Alex Bennée" <alex.bennee@linaro.org>,
	richard.henderson@linaro.org, f4bug@amsat.org,
	"Christian Ehrhardt" <christian.ehrhardt@canonical.com>,
	cota@braap.org, "Paolo Bonzini" <pbonzini@redhat.com>,
	aurelien@aurel32.net, "Richard Henderson" <rth@twiddle.net>
Subject: [PATCH v2 06/12] accel/tcg: better handle memory constrained systems
Date: Wed, 22 Jul 2020 07:28:56 +0100	[thread overview]
Message-ID: <20200722062902.24509-7-alex.bennee@linaro.org> (raw)
In-Reply-To: <20200722062902.24509-1-alex.bennee@linaro.org>

It turns out there are some 64 bit systems that have relatively low
amounts of physical memory available to them (typically CI system).
Even with swapping available a 1GB translation buffer that fills up
can put the machine under increased memory pressure. Detect these low
memory situations and reduce tb_size appropriately.

Fixes: 600e17b261
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Cc: BALATON Zoltan <balaton@eik.bme.hu>
Cc: Christian Ehrhardt <christian.ehrhardt@canonical.com>
Message-Id: <20200717105139.25293-6-alex.bennee@linaro.org>

---
v2
  - /4 to /8 as suggested by Christian
---
 accel/tcg/translate-all.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
index 2afa46bd2b1..3fe40ec1710 100644
--- a/accel/tcg/translate-all.c
+++ b/accel/tcg/translate-all.c
@@ -976,7 +976,12 @@ static inline size_t size_code_gen_buffer(size_t tb_size)
 {
     /* Size the buffer.  */
     if (tb_size == 0) {
-        tb_size = DEFAULT_CODE_GEN_BUFFER_SIZE;
+        size_t phys_mem = qemu_get_host_physmem();
+        if (phys_mem > 0 && phys_mem < (2 * DEFAULT_CODE_GEN_BUFFER_SIZE)) {
+            tb_size = phys_mem / 8;
+        } else {
+            tb_size = DEFAULT_CODE_GEN_BUFFER_SIZE;
+        }
     }
     if (tb_size < MIN_CODE_GEN_BUFFER_SIZE) {
         tb_size = MIN_CODE_GEN_BUFFER_SIZE;
-- 
2.20.1



  parent reply	other threads:[~2020-07-22  6:32 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-22  6:28 [PATCH v2 00/12] candidate fixes for 5.1-rc1 (testing, semihosting, OOM tcg, x86 fpu) Alex Bennée
2020-07-22  6:28 ` [PATCH v2 01/12] shippable: add one more qemu to registry url Alex Bennée
2020-07-22  6:28 ` [PATCH v2 02/12] semihosting: defer connect_chardevs a little more to use serialx Alex Bennée
2020-07-22  6:28 ` [PATCH v2 03/12] semihosting: don't send the trailing '\0' Alex Bennée
2020-07-22  6:28 ` [PATCH v2 04/12] util: add qemu_get_host_physmem utility function Alex Bennée
2020-07-22 15:51   ` Richard Henderson
2020-07-22  6:28 ` [PATCH v2 05/12] util/oslib-win32: add qemu_get_host_physmem implementation Alex Bennée
2020-07-22  6:49   ` Philippe Mathieu-Daudé
2020-07-22 10:03   ` Stefan Weil
2020-07-22 10:13     ` Daniel P. Berrangé
2020-07-22 11:33     ` Alex Bennée
2020-07-22 11:38       ` Daniel P. Berrangé
2020-07-22 10:32   ` 罗勇刚(Yonggang Luo)
2020-07-22 10:50     ` Stefan Weil
2020-07-22 11:31       ` Alex Bennée
2020-07-22 11:41         ` Daniel P. Berrangé
2020-07-22  6:28 ` Alex Bennée [this message]
2020-07-22 15:57   ` [PATCH v2 06/12] accel/tcg: better handle memory constrained systems Richard Henderson
2020-07-22 16:29     ` Alex Bennée
2020-07-22 16:44       ` Daniel P. Berrangé
2020-07-22 19:02         ` Richard Henderson
2020-07-23  9:00           ` Daniel P. Berrangé
2020-07-23  9:22             ` Alex Bennée
2020-07-23  9:31               ` Daniel P. Berrangé
2020-07-23 10:06                 ` Alex Bennée
2020-07-22  6:28 ` [PATCH v2 07/12] target/i386: floatx80: avoid compound literals in static initializers Alex Bennée
2020-07-22  6:45   ` Philippe Mathieu-Daudé
2020-07-22  6:28 ` [PATCH v2 08/12] linux-user: don't use MAP_FIXED in pgd_find_hole_fallback Alex Bennée
2020-07-22 16:00   ` Richard Henderson
2020-07-22  6:28 ` [PATCH v2 09/12] tests/docker: fix update command due to python3 str/bytes distinction Alex Bennée
2020-07-22  6:29 ` [PATCH v2 10/12] tests/docker: fix binfmt_misc image building Alex Bennée
2020-07-22  6:35   ` Philippe Mathieu-Daudé
2020-07-22  6:29 ` [PATCH v2 11/12] tests/docker: add support for DEB_KEYRING Alex Bennée
2020-07-22 14:27   ` Philippe Mathieu-Daudé
2020-07-22 16:03   ` Richard Henderson
2020-07-22  6:29 ` [PATCH v2 12/12] linux-user: fix clock_nanosleep() Alex Bennée
2020-07-22  6:49   ` Laurent Vivier
2020-07-22  8:33     ` Laurent Vivier
2020-07-22  8:55     ` Alex Bennée
2020-07-22 12:03       ` Laurent Vivier
2020-07-22  7:05   ` Philippe Mathieu-Daudé

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