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2005-09-11[PATCH] uclinux: add NULL check, 0 end valid check and some more exports to ↵Greg Ungerer
nommu.c Move call to get_mm_counter() in update_mem_hiwater() to be inside the check for tsk->mm being null. Otherwise you can be following a null pointer here. This patch submitted by Javier Herrero <jherrero@hvsistemas.es>. Modify the end check for munmap regions to allow for the legacy behavior of 0 being valid. Pretty much all current uClinux system libc malloc's pass in 0 as the end point. A hard check will fail on these, so change the check so that if it is non-zero it must be valid otherwise it fails. A passed in value will always succeed (as it used too). Also export a few more mm system functions - to be consistent with the VM code exports. Signed-off-by: Greg Ungerer <gerg@uclinux.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-08-04[PATCH] __vm_enough_memory() signedness fixSimon Derr
We have found what seems to be a small bug in __vm_enough_memory() when sysctl_overcommit_memory is set to OVERCOMMIT_NEVER. When this bug occurs the systems fails to boot, with /sbin/init whining about fork() returning ENOMEM. We hunted down the problem to this: The deferred update mecanism used in vm_acct_memory(), on a SMP system, allows the vm_committed_space counter to have a negative value. This should not be a problem since this counter is known to be inaccurate. But in __vm_enough_memory() this counter is compared to the `allowed' variable, which is an unsigned long. This comparison is broken since it will consider the negative values of vm_committed_space to be huge positive values, resulting in a memory allocation failure. Signed-off-by: <Jean-Marc.Saffroy@ext.bull.net> Signed-off-by: <Simon.Derr@bull.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-21[PATCH] Avoiding mmap fragmentationWolfgang Wander
Ingo recently introduced a great speedup for allocating new mmaps using the free_area_cache pointer which boosts the specweb SSL benchmark by 4-5% and causes huge performance increases in thread creation. The downside of this patch is that it does lead to fragmentation in the mmap-ed areas (visible via /proc/self/maps), such that some applications that work fine under 2.4 kernels quickly run out of memory on any 2.6 kernel. The problem is twofold: 1) the free_area_cache is used to continue a search for memory where the last search ended. Before the change new areas were always searched from the base address on. So now new small areas are cluttering holes of all sizes throughout the whole mmap-able region whereas before small holes tended to close holes near the base leaving holes far from the base large and available for larger requests. 2) the free_area_cache also is set to the location of the last munmap-ed area so in scenarios where we allocate e.g. five regions of 1K each, then free regions 4 2 3 in this order the next request for 1K will be placed in the position of the old region 3, whereas before we appended it to the still active region 1, placing it at the location of the old region 2. Before we had 1 free region of 2K, now we only get two free regions of 1K -> fragmentation. The patch addresses thes issues by introducing yet another cache descriptor cached_hole_size that contains the largest known hole size below the current free_area_cache. If a new request comes in the size is compared against the cached_hole_size and if the request can be filled with a hole below free_area_cache the search is started from the base instead. The results look promising: Whereas 2.6.12-rc4 fragments quickly and my (earlier posted) leakme.c test program terminates after 50000+ iterations with 96 distinct and fragmented maps in /proc/self/maps it performs nicely (as expected) with thread creation, Ingo's test_str02 with 20000 threads requires 0.7s system time. Taking out Ingo's patch (un-patch available per request) by basically deleting all mentions of free_area_cache from the kernel and starting the search for new memory always at the respective bases we observe: leakme terminates successfully with 11 distinctive hardly fragmented areas in /proc/self/maps but thread creating is gringdingly slow: 30+s(!) system time for Ingo's test_str02 with 20000 threads. Now - drumroll ;-) the appended patch works fine with leakme: it ends with only 7 distinct areas in /proc/self/maps and also thread creation seems sufficiently fast with 0.71s for 20000 threads. Signed-off-by: Wolfgang Wander <wwc@rentec.com> Credit-to: "Richard Purdie" <rpurdie@rpsys.net> Signed-off-by: Ken Chen <kenneth.w.chen@intel.com> Acked-by: Ingo Molnar <mingo@elte.hu> (partly) Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-05-17[PATCH] mm/nommu.c: try to fix __vmallocAdrian Bunk
Linus changed the second argument of __vmalloc from int to unsigned int breaking the compilation for CONFIG_MMU=n configurations (since he only changed vmalloc.c but not nommu.c). Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-16Linux-2.6.12-rc2Linus Torvalds
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!