From: Linus Torvalds <email@example.com> To: Andrew Morton <firstname.lastname@example.org> Cc: Ingo Molnar <email@example.com>, Rusty Russell <firstname.lastname@example.org>, <email@example.com> Subject: Re: [patch] 'sticky pages' support in the VM, futex-2.5.38-C5 Date: Thu, 26 Sep 2002 15:56:29 -0700 (PDT) [thread overview] Message-ID: <Pine.LNX.firstname.lastname@example.org> (raw) In-Reply-To: <Pine.LNX.email@example.com> On Thu, 26 Sep 2002, Linus Torvalds wrote: > > and then when we pin a page, we do > > /* This is part of the > struct page_change_struct pinned_data; That "This is part of the " comment should continue with "struct futex_q", but I went off and was supposed to check what the futex data structure was called, and forgot about updating it. Anyway, the point being that this needs no new allocations in _any_ path, and only extends a structure that we already need for the slow case for futexes. It does imply a new lock, though, and the COW path would have to check that hash (which should scale pretty well, since we only have entries here when somebody is blocked on a futex). Oh, and we need a new hash table, since the native futex hash can't just be re-used due to different indexing - the futex hash is based on physical page and offset, while the page_change_struct hash is based on virtual address and the mm. (I initially thought we could make the page_change_struct hash be based on physical page, but there can be multiple instances of the same physical page being mapped into the same VM, so that wouldn't be a good thing - we'd get callbacks for the wrong virtual address being COW'ed). Linus
next prev parent reply other threads:[~2002-09-26 22:48 UTC|newest] Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top 2002-09-26 11:30 Ingo Molnar 2002-09-26 15:01 ` Linus Torvalds 2002-09-26 22:09 ` Andrew Morton 2002-09-26 22:32 ` Linus Torvalds 2002-09-27 7:53 ` Ingo Molnar 2002-09-26 22:45 ` Linus Torvalds 2002-09-26 22:56 ` Linus Torvalds [this message] 2002-09-27 11:11 ` Ingo Molnar 2002-10-04 22:47 ` Jamie Lokier 2002-10-04 23:20 ` Linus Torvalds [not found] <200209261501.g8QF1pc02251@penguin.transmeta.com> 2002-09-26 15:27 ` Ingo Molnar 2002-09-26 16:48 ` Alan Cox 2002-09-27 8:05 Martin Wirth 2002-09-27 9:27 ` Ingo Molnar
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