The patch titled tcp.c: calculate tcp_mem based on low memory instead of all memory has been removed from the -mm tree. Its filename was tcpc-calculate-tcp_mem-based-on-low-memory-instead-of-all-memory.patch This patch was dropped because it was merged into mainline or a subsystem tree The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: tcp.c: calculate tcp_mem based on low memory instead of all memory From: Miquel van Smoorenburg <miquels@xxxxxxxxxx> I started upgrading a bunch of machines in my nntp server farm to a recent kernel- 2.6.25.x. They were running 2.6.11.12 on 32 bits, and I upgraded them to 2.6.25.x on 64 bits. All went fine until I noticed a few machines didn't have a 64 bit capable processor, so I had to keep them on a 32 bit kernel. These are machines with dual xeons 3 Ghz and 8 GB of RAM. On the 32 bit machines I keep getting the error below, and a flood of these on a 9600 baud serial console essentially kills the machine: diablo invoked oom-killer: gfp_mask=0xd0, order=0, oomkilladj=0 Pid: 4459, comm: diablo Not tainted 2.6.25.7-rc1 #1 [<c0249660>] oom_kill_process+0x120/0x210 [<c0227ff8>] __capable+0x8/0x20 [<c0249898>] badness+0x128/0x1c0 [<c0249b1c>] out_of_memory+0x17c/0x1c0 [<c024bdf4>] __alloc_pages+0x254/0x350 [<c03b75ad>] tcp_sendmsg+0x5cd/0xb50 [<c0381672>] sock_aio_write+0xe2/0x100 [<c02681e7>] do_sync_write+0xc7/0x110 [<c0232f20>] autoremove_wake_function+0x0/0x50 [<c0268af3>] vfs_write+0x133/0x140 [<c0269131>] sys_write+0x41/0x70 [<c0202e5e>] syscall_call+0x7/0xb After some investigation, I found out that the values of /proc/sys/net/ipv4/tcp_mem are quite different between these two versions: 2.6.11.12: $ cat tcp_mem 98304 131072 196608 2.6.25: # cat tcp_mem 804672 1072896 1609344 Somwehere between 2.6.11.12 and 2.6.25, the calculation method of the tcp_mem array was changed. Now 1609344 pages is 6.5 GB, and that will ofcourse never fit in x86_32's low memory .. I am not quite sure what the correct solution is here, I think something like the patch below. Alternatively we could use the existing calculation but limit 'limit' to 3/4 of (totalram_pages - totalhigh_pages) if (totalhigh_pages > 0) ? The tcp_mem array which contains limits on the total amount of memory used by TCP sockets is calculated based on nr_all_pages. On a 32 bits x86 system, we should base this on the number of lowmem pages. Signed-off-by: Miquel van Smoorenburg <miquels@xxxxxxxxxx> Cc: John Heffner <jheffner@xxxxxxx> Cc: David S. Miller <davem@xxxxxxxxxxxxx> Cc: <stable@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- net/ipv4/tcp.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff -puN net/ipv4/tcp.c~tcpc-calculate-tcp_mem-based-on-low-memory-instead-of-all-memory net/ipv4/tcp.c --- a/net/ipv4/tcp.c~tcpc-calculate-tcp_mem-based-on-low-memory-instead-of-all-memory +++ a/net/ipv4/tcp.c @@ -260,6 +260,8 @@ #include <linux/socket.h> #include <linux/random.h> #include <linux/bootmem.h> +#include <linux/highmem.h> +#include <linux/swap.h> #include <linux/cache.h> #include <linux/err.h> #include <linux/crypto.h> @@ -2620,7 +2622,7 @@ __setup("thash_entries=", set_thash_entr void __init tcp_init(void) { struct sk_buff *skb = NULL; - unsigned long limit; + unsigned long nr_pages, limit; int order, i, max_share; BUILD_BUG_ON(sizeof(struct tcp_skb_cb) > sizeof(skb->cb)); @@ -2689,8 +2691,9 @@ void __init tcp_init(void) * is up to 1/2 at 256 MB, decreasing toward zero with the amount of * memory, with a floor of 128 pages. */ - limit = min(nr_all_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT); - limit = (limit * (nr_all_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11); + nr_pages = totalram_pages - totalhigh_pages; + limit = min(nr_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT); + limit = (limit * (nr_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11); limit = max(limit, 128UL); sysctl_tcp_mem[0] = limit / 4 * 3; sysctl_tcp_mem[1] = limit; _ Patches currently in -mm which might be from miquels@xxxxxxxxxx are linux-next.patch scsi-dpt_i2o-is-bust-on-ia64.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html