Re: [patch 1/5] mm: exclude reserved pages from dirtyable memory
On Fri, Sep 30, 2011 at 09:17:20AM +0200, Johannes Weiner wrote: The amount of dirtyable pages should not include the full number of free pages: there is a number of reserved pages that the page allocator and kswapd always try to keep free. The closer (reclaimable pages - dirty pages) is to the number of reserved pages, the more likely it becomes for reclaim to run into dirty pages: +--+ --- | anon | | +--+ | | | | | | -- dirty limit new-- flusher new | file | | | | | | | | | -- dirty limit old-- flusher old | || +--+ --- reclaim | reserved | +--+ | kernel | +--+ This patch introduces a per-zone dirty reserve that takes both the lowmem reserve as well as the high watermark of the zone into account, and a global sum of those per-zone values that is subtracted from the global amount of dirtyable pages. The lowmem reserve is unavailable to page cache allocations and kswapd tries to keep the high watermark free. We don't want to end up in a situation where reclaim has to clean pages in order to balance zones. Not treating reserved pages as dirtyable on a global level is only a conceptual fix. In reality, dirty pages are not distributed equally across zones and reclaim runs into dirty pages on a regular basis. But it is important to get this right before tackling the problem on a per-zone level, where the distance between reclaim and the dirty pages is mostly much smaller in absolute numbers. Signed-off-by: Johannes Weiner jwei...@redhat.com Reviewed-by: Rik van Riel r...@redhat.com Reviewed-by: Minchan Kim minchan@gmail.com -- Kinds regards, Minchan Kim -- To unsubscribe from this list: send the line unsubscribe linux-btrfs in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Regression in btrfs-next: BUG at fs/btrfs/super.c:984!
After merging btrfs-next patches (chris' btrfs-3.0 branch) I get following error: [ 9799.199495] [ cut here ] [ 9799.199511] kernel BUG at fs/btrfs/super.c:984! [ 9799.199524] invalid opcode: [#1] PREEMPT SMP [ 9799.199539] CPU 1 [ 9799.199542] Modules linked in: cpufreq_stats btrfs zlib_deflate libcrc32c microcode reiserfs arc4 snd_hda_codec_conexant uvcvideo cdc_ether usbnet videodev v4l2_compat_ioctl32 cdc_acm cdc_wdm btusb snd_hda_intel iwlagn bluetooth mac80211 snd_hda_codec snd_hwdep snd_pcm cfg80211 snd_timer snd soundcore snd_page_alloc e1000e thinkpad_acpi hwmon rfkill nvram zcache(PC) zram(C) rtc_cmos tp_smapi thinkpad_ec psmouse fscache kvm_intel kvm loop configs ipv6 autofs4 uhci_hcd firewire_ohci sdhci_pci firewire_core sr_mod ehci_hcd sdhci mmc_core crc_itu_t cdrom sd_mod usbcore [ 9799.199657] [ 9799.199669] Pid: 2263, comm: df Tainted: P C 3.0.4-ck1+ #1 LENOVO 2242CTO/2242CTO [ 9799.199686] RIP: 0010:[a032b682] [a032b682] btrfs_statfs+0x108/0x3a9 [btrfs] [ 9799.199716] RSP: 0018:8800414f9de8 EFLAGS: 00010246 [ 9799.199728] RAX: 880129bf8000 RBX: 8800414f9f00 RCX: 880129bfa30c [ 9799.199742] RDX: 880129c8e240 RSI: 9123683e RDI: [ 9799.199756] RBP: 880129bf8000 R08: 810d1ad0 R09: 0203 [ 9799.199769] R10: 88012254eab0 R11: 0203 R12: 88011ba433c0 [ 9799.199783] R13: R14: 00885fa0 R15: 880129bfa368 [ 9799.199797] FS: 7f15983f7700() GS:88013bc8() knlGS: [ 9799.199811] CS: 0010 DS: ES: CR0: 80050033 [ 9799.199824] CR2: 015fa008 CR3: 8e5d5000 CR4: 000406e0 [ 9799.199838] DR0: DR1: DR2: [ 9799.199851] DR3: DR6: 0ff0 DR7: 0400 [ 9799.199865] Process df (pid: 2263, threadinfo 8800414f8000, task 8800b8426780) [ 9799.199878] Stack: [ 9799.199889] 8800414f9ed8 810d1ad0 88013162e4f8 [ 9799.199906] 880129f3c900 88012cdf3800 880129bf8000 000c430fe005 [ 9799.199923] 880132b0f540 88011badc958 880129bfa3c0 [ 9799.199940] Call Trace: [ 9799.199955] [810d1ad0] ? user_path_at+0x55/0x7b [ 9799.199971] [810e5f2c] ? statfs_by_dentry+0x46/0x5d [ 9799.199985] [810e5f56] ? vfs_statfs+0x13/0x8b [ 9799.19] [810d1ad0] ? user_path_at+0x55/0x7b [ 9799.26] [810e5ffe] ? user_statfs+0x30/0x48 [ 9799.26] [810e6068] ? sys_statfs+0x12/0x2b [ 9799.26] [8136607b] ? system_call_fastpath+0x16/0x1b [ 9799.26] Code: 18 48 89 33 4c 89 6b 20 48 89 43 08 48 8b 44 24 28 48 8b 80 20 01 00 00 48 8b 90 b8 23 00 00 48 89 44 24 30 8b 7a 30 85 ff 75 02 0f 0b 48 63 ff be 50 00 00 00 48 89 54 24 20 48 c1 e7 05 e8 56 [ 9799.26] RIP [a032b682] btrfs_statfs+0x108/0x3a9 [btrfs] [ 9799.26] RSP 8800414f9de8 [ 9799.221655] ---[ end trace 327e64ade405e154 ]--- PS. It might happened that it was caused by parition mounted read-only on read-only block device. signature.asc Description: This is a digitally signed message part
