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[78.12.229.84]) by smtp.gmail.com with ESMTPSA id u10sm1537758wrg.6.2018.01.16.06.18.43 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 16 Jan 2018 06:18:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references; bh=qYWXZqmOnjr9kRe2Z16W/eCWt4E2/uIIod4+4Q08MO4=; b=Ivkc3NbZNmsywg0P16uDaBWm6emxFTIDtKHNf2xxpRaeylKEAvslCpCMk/szz8SVCc n/Nsg7eaZWLoy35+/7e4CHA7ObGOJ6uopjkQQGBhsc1HV2ahLRf940lLDPaZCOWrgWOg PpHZdVY+rEcCXy5VVZsv0ezqDGdIhbUTAsxekqknpBs74yDPSvxlEzAEGaqj5CS0mw1q v5Y7C12I+D4uSyfPHT58N2e1e9O1fRgAxmUeZdJtOXn6sJO2VVnGRFev/cRJwk+Zc+9e sZapzh0zdQkqA2mu1b9goCV+zU10MjgURvlwo3wGSOwNYZXSDRF09ueFscOBrrIpxjUJ 7tBQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :in-reply-to:references; bh=qYWXZqmOnjr9kRe2Z16W/eCWt4E2/uIIod4+4Q08MO4=; b=UgPffdmI1oR+XQM0+lEcqab3bT92ZCFFanJwkWwRFr0tUR3laawzxiQXORCT2EH1ys b/6C8x7Z48XNevhQPVAaHniQZ6OvS8zpN+0uXxArTOzw/Xk9l4rCqbEPRIQYz+o75WnO cdU00KBL/1UeiE2kylzGv66k5VZj8deajNCnv6tzInCWr6DX9LAaEtJ4b5Ens2f9TKGW ADZ/7duEqyRqUfEyCGEvhwUlErCOuh4hhG+PD+Z8hrCLGp0FtwN6K8N064AyYq5ixsY2 suNh+87CbPO4YvRPZOqakDYJ/hAzSe7RGaw0jnN3nR7dr9tYNC3IP2FOgLMJcKPdv8Zt V7JA== X-Gm-Message-State: AKwxytfVvCEgwoVVM+OnjzWXMdgNpMYA6o1blqbOe7y3b9MSyKHRWdns C44V52JHBs4uoAgSiNgQu0AMnx8K X-Google-Smtp-Source: ACJfBotUCxWdobnfC3zkwilNQHbqfCHjpPAVu6aFtRCspiABMA8QEcJAJBPdFzlbnRL2eGkfPmAXOg== X-Received: by 10.28.152.142 with SMTP id a136mr13598326wme.71.1516112325068; Tue, 16 Jan 2018 06:18:45 -0800 (PST) From: Paolo Bonzini To: qemu-devel@nongnu.org Date: Tue, 16 Jan 2018 15:17:28 +0100 Message-Id: <1516112253-14480-47-git-send-email-pbonzini@redhat.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1516112253-14480-1-git-send-email-pbonzini@redhat.com> References: <1516112253-14480-1-git-send-email-pbonzini@redhat.com> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2a00:1450:400c:c09::242 Subject: [Qemu-devel] [PULL 46/51] find_ram_offset: Add comments and tracing X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Dr. David Alan Gilbert" Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) X-ZohoMail: RDKM_2 RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" From: "Dr. David Alan Gilbert" Add some comments so I can understand the various nested loops. Add some tracing so I can see what they're doing. Signed-off-by: Dr. David Alan Gilbert Message-Id: <20180105170138.23357-2-dgilbert@redhat.com> Signed-off-by: Paolo Bonzini --- exec.c | 29 ++++++++++++++++++++++------- trace-events | 4 ++++ 2 files changed, 26 insertions(+), 7 deletions(-) diff --git a/exec.c b/exec.c index 4722e52..5e2fb55 100644 --- a/exec.c +++ b/exec.c @@ -1660,7 +1660,10 @@ static void *file_ram_alloc(RAMBlock *block, } #endif =20 -/* Called with the ramlist lock held. */ +/* Allocate space within the ram_addr_t space that governs the + * dirty bitmaps. + * Called with the ramlist lock held. + */ static ram_addr_t find_ram_offset(ram_addr_t size) { RAMBlock *block, *next_block; @@ -1673,19 +1676,29 @@ static ram_addr_t find_ram_offset(ram_addr_t size) } =20 RAMBLOCK_FOREACH(block) { - ram_addr_t end, next =3D RAM_ADDR_MAX; + ram_addr_t candidate, next =3D RAM_ADDR_MAX; =20 - end =3D block->offset + block->max_length; + candidate =3D block->offset + block->max_length; =20 + /* Search for the closest following block + * and find the gap. + */ RAMBLOCK_FOREACH(next_block) { - if (next_block->offset >=3D end) { + if (next_block->offset >=3D candidate) { next =3D MIN(next, next_block->offset); } } - if (next - end >=3D size && next - end < mingap) { - offset =3D end; - mingap =3D next - end; + + /* If it fits remember our place and remember the size + * of gap, but keep going so that we might find a smaller + * gap to fill so avoiding fragmentation. + */ + if (next - candidate >=3D size && next - candidate < mingap) { + offset =3D candidate; + mingap =3D next - candidate; } + + trace_find_ram_offset_loop(size, candidate, offset, next, mingap); } =20 if (offset =3D=3D RAM_ADDR_MAX) { @@ -1694,6 +1707,8 @@ static ram_addr_t find_ram_offset(ram_addr_t size) abort(); } =20 + trace_find_ram_offset(size, offset); + return offset; } =20 diff --git a/trace-events b/trace-events index 3695959..ec95e67 100644 --- a/trace-events +++ b/trace-events @@ -55,6 +55,10 @@ dma_complete(void *dbs, int ret, void *cb) "dbs=3D%p ret= =3D%d cb=3D%p" dma_blk_cb(void *dbs, int ret) "dbs=3D%p ret=3D%d" dma_map_wait(void *dbs) "dbs=3D%p" =20 +# # exec.c +find_ram_offset(uint64_t size, uint64_t offset) "size: 0x%" PRIx64 " @ 0x%= " PRIx64 +find_ram_offset_loop(uint64_t size, uint64_t candidate, uint64_t offset, u= int64_t next, uint64_t mingap) "trying size: 0x%" PRIx64 " @ 0x%" PRIx64 ",= offset: 0x%" PRIx64" next: 0x%" PRIx64 " mingap: 0x%" PRIx64 + # memory.c memory_region_ops_read(int cpu_index, void *mr, uint64_t addr, uint64_t va= lue, unsigned size) "cpu %d mr %p addr 0x%"PRIx64" value 0x%"PRIx64" size %= u" memory_region_ops_write(int cpu_index, void *mr, uint64_t addr, uint64_t v= alue, unsigned size) "cpu %d mr %p addr 0x%"PRIx64" value 0x%"PRIx64" size = %u" --=20 1.8.3.1