From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx184.postini.com [74.125.245.184]) by kanga.kvack.org (Postfix) with SMTP id 108796B005A for ; Tue, 8 Jan 2013 12:52:08 -0500 (EST) Received: by mail-vb0-f41.google.com with SMTP id l22so668323vbn.14 for ; Tue, 08 Jan 2013 09:52:07 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <20130108173747.GF9163@redhat.com> References: <20130105152208.GA3386@redhat.com> <20130108163141.GA27555@shutemov.name> <20130108173747.GF9163@redhat.com> From: Linus Torvalds Date: Tue, 8 Jan 2013 09:51:47 -0800 Message-ID: Subject: Re: oops in copy_page_rep() Content-Type: multipart/mixed; boundary=047d7b6daa70b8ee0404d2ca9a58 Sender: owner-linux-mm@kvack.org List-ID: To: Andrea Arcangeli Cc: "Kirill A. Shutemov" , Hillf Danton , Hugh Dickins , Dave Jones , Linux Kernel , Andrew Morton , Mel Gorman , Linux-MM , Rik van Riel --047d7b6daa70b8ee0404d2ca9a58 Content-Type: text/plain; charset=ISO-8859-1 On Tue, Jan 8, 2013 at 9:37 AM, Andrea Arcangeli wrote: > > The reason it returned to userland and retried the fault is that this > should be infrequent enough not to worry about it and this was > marginally simpler but it could be changed. Yeah, that was my suspicion. And as mentioned, returning to user land might actually help with scheduling and/or signal handling latencies etc, so it might be the right thing to do. Especially if the alternative is to just busy-loop. > If we don't want to return to userland we should wait on the splitting > bit and then take the pte walking routines like if the pmd wasn't > huge. This is not related to the below though. How does this patch sound to people? It does the splitting check before the access bit set (even though I don't think it matters), and at least talks about the alternatives and the issues a bit. Hmm? Linus --047d7b6daa70b8ee0404d2ca9a58 Content-Type: application/octet-stream; name="mm.patch" Content-Disposition: attachment; filename="mm.patch" Content-Transfer-Encoding: base64 X-Attachment-Id: f_hbpc6e9i0 IG1tL21lbW9yeS5jIHwgMTIgKysrKysrKysrKysrCiAxIGZpbGUgY2hhbmdlZCwgMTIgaW5zZXJ0 aW9ucygrKQoKZGlmZiAtLWdpdCBhL21tL21lbW9yeS5jIGIvbW0vbWVtb3J5LmMKaW5kZXggNDlm YjFjZjA4NjExLi5mNWVjM2FlMDNmNDQgMTAwNjQ0Ci0tLSBhL21tL21lbW9yeS5jCisrKyBiL21t L21lbW9yeS5jCkBAIC0zNzE1LDYgKzM3MTUsMTggQEAgcmV0cnk6CiAJCQkJcmV0dXJuIGRvX2h1 Z2VfcG1kX251bWFfcGFnZShtbSwgdm1hLCBhZGRyZXNzLAogCQkJCQkJCSAgICAgb3JpZ19wbWQs IHBtZCk7CiAKKwkJCS8qCisJCQkgKiBJZiB0aGUgcG1kIGlzIHNwbGl0dGluZywgcmV0dXJuIGFu ZCByZXRyeSB0aGUKKwkJCSAqIHRoZSBmYXVsdC4gV2UgKmNvdWxkKiBzZXQganVzdCB0aGUgYWNj ZXNzZWQgZmxhZywKKwkJCSAqIGJ1dCBpdCdzIGJldHRlciB0byBqdXN0IGF2b2lkIHRoZSByYWNl cyB3aXRoCisJCQkgKiBzcGxpdHRpbmcgZW50aXJlbHkuCisJCQkgKgorCQkJICogQWx0ZXJuYXRp dmU6IHdhaXQgdW50aWwgdGhlIHNwbGl0IGlzIGRvbmUsIGFuZAorCQkJICogZ290byByZXRyeS4K KwkJCSAqLworCQkJaWYgKHBtZF90cmFuc19zcGxpdHRpbmcob3JpZ19wbWQpKQorCQkJCXJldHVy biAwOworCiAJCQlpZiAoZGlydHkgJiYgIXBtZF93cml0ZShvcmlnX3BtZCkpIHsKIAkJCQlyZXQg PSBkb19odWdlX3BtZF93cF9wYWdlKG1tLCB2bWEsIGFkZHJlc3MsIHBtZCwKIAkJCQkJCQkgIG9y aWdfcG1kKTsK --047d7b6daa70b8ee0404d2ca9a58-- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org