lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Date:	Tue, 19 Jun 2007 15:59:30 +0530
From:	"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
To:	alex@...sterfs.com, linux-ext4 <linux-ext4@...r.kernel.org>
Subject: ext4-block-reservation.patch

Hi,

In block reservation code while rebalancing the free blocks why are we not 
looking at the reservation slots that have no free blocks left.  Rebalancing
the free blocks equally across all the reservation slots will make sure
we have less chances of failure later when we try to reserve blocks. 


I understand that we consider the CPU slot on which reservation failed while
rebalancing. But what is preventing considering other CPU slot that might have
zero blocks left ?




+void ext4_rebalance_reservation(struct ext4_reservation_slot *rs, __u64 free)
+{
+       int i, used_slots = 0;
+       __u64 chunk;
+
+       /* let's know what slots have been used */
+       for (i = 0; i < NR_CPUS; i++)
+               if (rs[i].rs_reserved || i == smp_processor_id())
+                       used_slots++;
+
+       /* chunk is a number of block every used
+        * slot will get. make sure it isn't 0 */
+       chunk = free + used_slots - 1;
+       do_div(chunk, used_slots);
+
+       for (i = 0; i < NR_CPUS; i++) {
+               if (free < chunk)
+                       chunk = free;
+               if (rs[i].rs_reserved || i == smp_processor_id()) {
+                       rs[i].rs_reserved = chunk;
+                       free -= chunk;
+                       BUG_ON(free < 0);
+               }
+       }
+       BUG_ON(free);
+}


-aneesh
-
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Powered by blists - more mailing lists